Activated sludge

J Ind Microbiol Biotechnol, 1997 Apr, 18(4), 267 - 71
Diversity of isolates of Acinetobacter from activated sludge systems based on their whole cell protein patterns; Maszenan AM et al.; Whole cell protein extracts from strains of the currently recognized genomic species of Acinetobacter, together with those from a range of isolates of several genomic species identified using the Biolog system and obtained from a biological nutrient-removal activated sludge plant were analysed by SDS-PAGE . The dendrograms obtained after numerical analysis for the known genomic species generally supported the taxonomic relationships suggested from earlier DNA-DNA hybridisation data . In some cases the activated sludge isolates identified to genomic species level clustered closely with the corresponding genomic species reference strains, although isolates 5 and 8/9 were scattered throughout the dendrogram . Considerable variations were seen in the protein patterns of the 27 different environmental isolates of genomic species 7 that were analysed . Three unidentified Acinetobacter isolates examined formed their own subcluster.

J Appl Microbiol, 1997 Apr, 82(4), 405 - 10
Phenotypic and phylogenetic description of an Italian isolate of "Microthrix parvicella"; Rossetti S et al.; "Microthrix parvicella" strain RN1 was isolated from an activated sludge treatment plant in Italy using micromanipulation techniques . The strain grows as thin unbranchedfilaments which are Gram-positive with Neisser-positive granules . The isolate was characterized by analysis of the 16S rDNA which was amplified directly from cell biomass by the polymerase chain reaction and sequenced . "Microthrix parvicella" strain RN1 presents a very high similarity (100%) with another "M . parvicella" strain recently isolated in Australia, suggesting that this micro-organism, a novel, deep branching member of the actinomycetes subphylum, is the same causing the common events of bulking and foaming phenomena in activated sludge treatment plants throughout the world.

Appl Environ Microbiol, 1997 Mar, 63(3), 1107 - 17
Group-specific small-subunit rRNA hybridization probes to characterize filamentous foaming in activated sludge systems; de los Reyes FL et al.; Foaming in activated sludge systems is characterized by the formation of a thick, chocolate brown-colored scum that floats on the surface of aeration basins and secondary clarifiers . These viscous foams have been associated with the presence of filamentous mycolic acid-containing actinomycetes . To aid in evaluating the microbial representation in foam, we developed and characterized group-, genus-, and species-specific oligonucleotide probes targeting the small subunit rRNA of the Mycobacterium complex, Gordona spp., and Gordona (Nocardia) amarae, respectively . The use of a universal base analog, 5-nitroindole, in oligonucleotide probe design was evaluated by comparing the characteristics of two different versions of the Mycobacterium complex probe . The temperature of dissociation of each probe was determined . Probe specificity studies with a diverse collection of 67 target and nontarget rRNAs demonstrated the specificity of the probes to the target groups . Whole-cell hybridizations with fluorescein- and rhodamine-labeled probes were performed with pure cultures of various members of the Mycobacterium complex as well as with environmental samples from a full-scale activated sludge plant which experienced foaming . Quantitative membrane hybridizations with activated sludge and anaerobic digester foam showed that 15.0 to 18.3% of the total small-subunit rRNAs could be attributed to members of the Mycobacterium complex, of which a vast majority consisted of Gordona rRNA . Several G . amarae strains made up only a very small percentage of the Gordona strains present . We demonstrated that group-specific rRNA probes are useful tools for the in situ monitoring and identification of filamentous bacteria in activated sludge systems.

Microbios, 1997, 89(359), 105 - 17
Acinetobacter radioresistens metabolizing aromatic compounds . 2 . Biochemical and microbiological characterization of the strain; Pessione E et al.; The metabolic potentialities of an Acinetobacter radioresistens strain, isolated from the soil adjacent to an activated sludge plant, were investigated . Among 26 aromatic substrates tested, only phenol, benzoate and catechol were metabolized . Since this strain possessed abundant plasmid DNA, the antibiotic and heavy metal resistance was examined, and the bacterial cells proved to be sensitive to all metals (Ni, Tl, Pb, Cd, Ag, Co, Zn) and antibiotics tested except for Fosfomycin and chloramphenicol . The degradation kinetics for phenol and benzoate as the sole carbon/energy source (pH 7, 30 degrees C) displayed different trends, confirmed by the bacterial growth curve . Crude extracts from phenol-grown cultures showed both phenol hydroxylating activity and catechol dioxygenating activity . Phenol hydroxylase possessed a reductase component able to reduce nitroblue tetrazolium (NBT) and cytochrome C, thus exhibiting differences from previously reported monocomponent phenol hydroxylases from the same genus . Catechol dioxygenase is an intradiol-cleaving enzyme recognizing also substituted catechols.

J Basic Microbiol, 1997, 37(2), 129 - 37
Diversity within bacterial isolates hybridizing with Comamonas probe ppT; Koivula TT et al.; Diversity within bacteria isolated from activated sludge and the Baltic sea and recognized by the rRNA targeted oligonucleotide probe ppT (designed by BRAUN-HOWLAND et al., 1993 to recognize C . testosteroni) was studied . The partial nucleotide sequences of 16S genes of the isolates revealed that the activated sludge and Baltic sea isolates each formed a separate group distinct from C . testosteroni . The analysis of phage and bacteriocin sensitivity as well as whole cell protein patterns revealed the same grouping, but in these characters also intragroup variation was observed . As a conclusion, neither of the studied groups were C . testosteroni, but they probably belong to two previously unknown species common in activated sludge or the Baltic sea.

Can J Microbiol, 1997 Jan, 43(1), 97 - 101
Biodegradation of N-phosphonomethyliminodiacetic acid by microorganisms from industrial activated sludge; Carson DB et al.; A microbial population that biodegraded N-phosphonomethyliminodiacetic acid (PIA), a key component of glyphosate (N-phosphonomethylglycine) process waste, was established . The stoichiometric conversion of PIA to aminomethylphosphonic acid (AMPA) was observed in a laboratory sequencing batch reactor (SBR) containing activated sludge from a glyphosate-manufacturing facility and PIA as sole source of carbon . PIA degradation was determined by high-performance liquid chromatography and confirmed by radiolabeled studies . Greater than 90% of the {carboxymethyl-2-14C}-label of PIA was released as 14CO2 in 7 days using samples of sludge from the SBR . The cycle time required to biodegrade up to 7.5 mM PIA in SBRs was reduced from 21 to < 3 days . PIA biodegradation was also established in an immobilized bacteria column inoculated with mixed liquor from a SBR; > 99% PIA removal was achieved at an influent concentration of 2.2 mM and a hydraulic retention time of < 10 h . A pure bacterial culture was isolated from a SBR by streaking samples of sludge on solid media with PIA as sole carbon source . The isolate was identified as Xanthomonas maltophilia . In liquid culture, X . maltophilia degraded up to 4.4 mM PIA within 10 days and produced stoichiometric amounts of AMPA . The results demonstrate the biodegradation of PIA and suggest the potential for its treatment in industrial biological treatment systems.

Appl Microbiol Biotechnol, 1997 Jan, 47(1), 69 - 72
Biodegradation of methyl t-butyl ether by pure bacterial cultures; Mo K et al.; Three pure bacterial cultures degrading methyl t-butyl ether (MTBE) were isolated from activated sludge and fruit of the Gingko tree . They have been classified as belonging to the genuses Methylobacterium, Rhodococcus, and Arthrobacter . These cultures degraded 60 ppm MTBE in 1-2 weeks of incubation at 23-25 degrees C . The growth of the isolates on MTBE as sole carbon source is very slow compared with growth on nutrient-rich medium . Uniformly-labeled {14C}MTBE was used to determine 14CO2 evolution . Within 7 days of incubation, about 8% of the initial radioactivity was evolved as 14CO2 . These strains also grow on t-butanol, butyl formate, isopropanol, acetone and pyruvate as carbon sources . The presence of these compounds in combination with MTBE decreased the degradation of MTBE . The cultures pregrown on pyruvate resulted in a reduction in 14CO2 evolution from {14C}MTBE . The availability of pure cultures will allow the determination of the pathway intermediates and the rate-limiting steps in the degradation of MTBE.

Chemosphere, 1996 Dec, 33(12), 2533 - 42
Biological treatment of dye wastewaters using an anaerobic-oxic system; An H et al.; Three dye solutions, namely, C.I . Acid Yellow 17, C.I . Basic Blue 3, and C.I . Basic Red 2, were treated in an upflow anaerobic sludge blanket (UASB) reactor followed by a semi-continuous aerobic activated sludge tank . When hydraulic retention time was about 12 hours, no significant color removal was observed in the aerobic stage . In the anaerobic stage, Acid Yellow 17, Basic Blue 3, and Basic Red 2 were removed by 20%, 72%, and 78%, respectively . To treat wastewater from a dye manufacturing factor with COD concentration of 1200 mg/l and Color of 500 degrees (dilution factor), an UASB reactor (4.5 liters) and an activated sludge tank (5 liters, adjustable), COD and color were removed by more than 83% and 90% at a COD loading rate of 5.3 kg COD/m3-day in the anaerobic stage, and at the hydraulic retention time of 6-10 hours for the anaerobic stage and 6.5 for the aerobic stage . The anaerobic stage of the A/O system removes both color and COD . In addition, it also improves biodegradability of dyes for further aeroic treatment.

Int J Food Microbiol, 1996 Dec, 33(2-3), 245 - 56
Pathogenic micro-organisms in slaughterhouse sludge--a survey; Fransen NG et al.; During slaughtering of animals and subsequent meat processing the process water used becomes polluted with organic matter of animal origin (i.e . protein and fat) . This organic sludge is, in principle, a product suitable for animal feeding . To investigate the microbiological contamination level of sludge, raw sludge was collected at pig (n = 8) and poultry (n = 5) slaughterhouses . Both flocculated and aerobically activated sludge was monitored . Slaughterhouse sludge was heavily contaminated with Enterobacteriaceae (6.3-10.0 in log10 N/gram dry matter) and enterococci (4.6-7.9) . Clostridia were present in sludge at a level of 3.1-5.8 (in log10 N/g DM) . Salmonella was present in the sludge from all slaughterhouses examined . Yersinia enterocolitica serotypes O:3 and O:9 were found in sludge from seven out of thirteen slaughterhouses . The prevalence of Campylobacter jejuni/coli was higher in flocculated poultry sludge than in both flocculated pig sludge and aerobically activated pig sludge . Obviously, decontamination of the sludge is mandatory when it is to be applied as a feed constituent, to prevent bacterial cycles from occurring in livestock, as well as the spread of human pathogenic zoonoses like campylobacter, salmonella and yersinia, to minimize loss of protein quality by the microbial breakdown of amino acids and the formation of possible toxic metabolites in sludge during storage.

Appl Environ Microbiol, 1996 Oct, 62(10), 3901 - 4
Identification of a functionally important population in phenol-digesting activated sludge with antisera raised against isolated bacterial strains; Watanabe K et al.; Antisera were raised against nine strains which had been isolated from phenol-acclimated oil refinery activated sludge . Although several antisera reacted significantly with the activated sludge during a period of adaptation to phenol, only an antiserum against one of the isolates, Alcaligenes sp . E2, reacted with the activated sludge after the adaptation period . A kinetic pattern of phenol-oxygenating activity of the activated sludge after the adaptation period was similar to that of strain E2 . These results suggest that a functionally important population in the phenol-digesting activated sludge was serologically identified.

J Toxicol Environ Health, 1996 Sep, 49(1), 67 - 82
Aquatic risk assessment of a polycarboxylate dispersant polymer used in laundry detergents; Hamilton JD et al.; Polycarboxylates enhance detergent soil removal properties and prevent encrustation of calcium salts on fabrics during washing . Laundry wastewater typically reaches wastewater treatment plants, which then discharge into aquatic environments . The yearly average concentration of a 4500 molecular weight (MW) sodium acrylate homopolymer reaching U.S . wastewater treatment plants will be approximately 0.7 mg/L . Publications showing the low to moderate acute aquatic toxicity of polycarboxylates are readily available . However, there are no published evaluations that estimate wastewater removal and characterize the probability of exceedance of acceptable chronic aquatic exposure . WW-TREAT can be used to estimate removal during wastewater treatment and PG-GRIDS can be applied to characterize risk for exceedance in wastewater treatment plant outfalls . After adjustments for the MW distribution of the homopolymer, WW-TREAT predicted that 6.5% will be removed in primary treatment plants and 60% will be removed in combined primary and activated sludge treatment plants . These estimates are consistent with wastewater fate tests, but underestimate homopolymer removal when homopolymer precipitation is included . Acceptable levels of chronic outfall (receiving water) exposure were based on aquatic toxicity testing in algae, fish, and Daphnia magna . PG-GRIDS predicted that no unreasonable risk for exceedance of acceptable chronic exposure will occur in the outfalls of U.S . wastewater plants . Future development of wastewater treatment models should consider polymer MW distribution and precipitation as factors that may alter removal of materials from wastewater.

Appl Environ Microbiol, 1996 Aug, 62(8), 2687 - 91
Comamonas testosteroni colony phenotype influences exopolysaccharide production and coaggregation with yeast cells; Bossier P et al.; A Comamonas testosteroni strain was isolated from activated sludge on the basis of its ability to coaggregate with yeast cells . On agar plates the following two types of colonies were formed: colonies with a mucoid appearance and colonies with a nonmucoid appearance . On plates this strain alternated between the two forms, making sectored colonies . In liquid medium with constant agitation no such change was observed . In the absence of agitation and in contact with a glass surface a culture with predominantly nonmucoid-colony-forming cells very rapidly shifted to a culture dominated by mucoid-colony-forming cells . In liquid medium the reverse was observed under stress conditions imposed by hydrogen peroxide, sodium dodecyl sulfate, or starvation . Nonmucoid cells formed very rapidly settling flocs with yeast cells, while coaggregation of mucoid cells with yeast cells did not occur . These findings may be relevant to the behavior of activated sludge microbial communities.

Appl Environ Microbiol, 1996 Jul, 62(7), 2644 - 6
Effects of atrazine on Ochrobactrum anthropi membrane fatty acids; Laura D et al.; Ochrobactrum anthropi is a gram-negative bacillus recognized as a human opportunist pathogen isolated in clinical specimens and not of clinical significance . We report a new aspect of this bacterium, that it has been isolated from activated sludge . In fact, it is able to grow on atrazine (2-chloro-4-ethylamino-6-isopropyl-amine-s-triazine) by utilizing it as the only source of carbon . Our results show that atrazine (0.03 g/liter) causes a dramatical increase in the degree of saturation of membrane fatty acids . Analysis and identification of bacterial fatty acids were performed by gas chromatography and gas chromatography-mass spectrometry techniques.

Microb Ecol, 1996 Jul, 32(2), 101 - 21
Characterization of Bacterial Communities from Activated Sludge: Culture-Dependent Numerical Identification Versus In Situ Identification Using Group- and Genus-Specific rRNA-Targeted Oligonucleotide Probes
Kampfer P, Erhart R, Beimfohr C, Bohringer J, Wagner M, Amann R.
The structures of bacterial communities were studied in activated sludge samples obtained from the aerobic and anaerobic zones of a wastewater treatment plant showing enhanced phosphorous removal . Samples were analyzed by in situ hybridization with oligonucleotide probes complementary to selected regions of the 16S and 23S ribosomal RNA (rRNA) characteristic for defined phylogenetic entities (genera and larger groups) . The microbial community structures revealed by molecular techniques were compared with the compositions of culturable bacterial communities, obtained from the characterization of 255 isolates from tryptone-soy (TS) agar and R2A agar . These isolates were characterized by 89 physiological tests and their cellular fatty acid patterns, and identified . Culture-dependent techniques indicated the following distribution: different Aeromonas spp . (2.7-8.3% on R2A agar; 45.0-63.7% on TS agar), Acinetobacter spp . (5.4-9.0% on R2A agar; 5.0-9.1% on TS agar), Pseudomonas spp . (up to 10% on R2A agar) and Shewanella putrefaciens (up to 3.0% on R2A agar), all members of the gamma subclass of Proteobacteria, were isolated most frequently . The relatively rare isolates of the beta subclass were identified as Acidovorax spp., Alcaligenes spp., and Comamonas spp. . The Gram-positive bacteria (high DNA G+C) were assigned mainly to Arthrobacter spp., Microbacterium spp., and Mycobacterium phlei . In order to assess the in situ abundance of the most frequently isolated genus, Aeromonas, two rRNA-targeted oligonucleotide probes were developed . The two gamma proteobacterial genera Aeromonas and Acinetobacter constituted less than 5% of all bacteria . In situ, Proteobacteria belonging to the beta subclass and high G+C Gram-positive bacteria were dominant . From filamentous bacteria, Sphaerotilus spp . and Leptothrix spp . could be detected occasionally . In addition, one sample contained a high proportion of the morphologically distinct filaments of Microthrix parvicella.

Ecotoxicol Environ Saf, 1996 Jun, 34(1), 85 - 93
Estimating the removal and biodegradation potential of radiolabeled organic chemicals in activated sludge; Shimp RJ et al.; A two-step procedure is described to characterize the removal and biodegradation potential of nonvolatile 14C-labeled organic compounds in activated sludge . In the first step, trace concentrations of radiolabeled test materials are dosed in influent wastewater to continuous-flow activated sludge (CAS) systems which have been previously exposed or acclimated to unlabeled test material . Radiolabel is quantified in influent, effluent, and activated sludge mixed liquor to determine total 14C removal and partitioning of radiolabel in solid and liquid compartments . The 14C data are used to calculate the amount of removal due to sorption and biodegradation and to estimate the apparent sorption coefficients for 14C activity to activated sludge solids . The 14C-labeled CAS studies are followed by biodegradation studies in batch-activated sludge (BAS) systems using sludge derived from the CAS system . The kinetics of biodegradation (defined as mineralization to 14CO2) are measured in the BAS system to confirm the CAS biodegradation results and generate mineralization rate constants for kinetic modeling . The two-step procedure was applied to radiolabeled anionic (linear alkylbenzene sulfonate) and cationic (dodecyltrimethylammonium chloride, distearyldimethylammonium chloride) surfactants which differed greatly in their biodegradation and sorption profiles . Laboratory removal figures for these materials were comparable to values measured in full-scale wastewater treatment systems, although the amount of removal due to sorption and biodegradation varied significantly for the different surfactants . In general, the 14C method has several advantages over standard methods used in the United States and Europe which employ unlabeled materials . These advantages include the use of realistic concentrations and test conditions for acclimating and dosing activated sludge microorganisms and the ability to generate partitioning and kinetic constants that can be used more broadly in environmental fate and exposure models.

Biodegradation, 1996 Jun, 7(3), 257 - 65
Degradation of olestra, a non caloric fat replacer, by microorganisms isolated from activated sludge and other environments; Lee DM et al.; Olestra is a non-caloric fat substitute consisting of fatty acids esterified to sucrose . Previous work has shown that olestra is not metabolized in the gut and is excreted unmodified in human feces . To better understand the fate of olestra in engineered and natural environments, aerobic bacteria and fungi that degrade olestra were enriched from sewage sludges, soils and municipal solid waste compost not previously exposed to olestra . Various mixed and pure cultures were obtained from these sources which were able to utilize olestra as a sole carbon and energy source . The fastest growing enrichment was obtained from activated sludge and later yielded an olestra-degrading pure culture of Pseudomonas aeruginosa . This mixed culture extensively degraded both 14C-fatty acid labeled olestra and 14C-sucrose labeled olestra during 8 days of incubation . Longer-term incubation with pure cultures of P.aeruginosa demonstrated that > 98% of 14C-sucrose labeled olestra and > 72% of 14C-fatty acid labeled olestra was mineralized to CO2 after 69 days . These results indicate that olestra degraders are present in environments not previously exposed to olestra and that olestra can serve as a sole carbon and energy source . Furthermore, a common bacterial species was isolated from activated sludge and shown to have the ability to degrade olestra.

Appl Microbiol Biotechnol, 1996 Jun, 45(5), 719 - 22
Aerobic and anaerobic biodegradability of 1-anthraquinone sulphonate; Seignez C et al.; The present work investigates 1-anthraquinone sulphonate (1-AS) biodegradation under (i) aerobic conditions using domestic activated sludge as inoculum, (ii) anaerobic conditions using sludge from an anaerobic domestic wastewater treatment digester in a sulphate-containing or methanogenic environment, (iii) a combination of anaerobic followed by aerobic conditions . The process was evaluated in terms of primary degradation, i.e . 1-AS elimination and ultimate degradation, as total dissolved organic carbon removal . It was shown that aerobic conditions lead to the complete primary and ultimate degradation, of 1-AS . By contrast, neither under sulphato-reductive nor methanogenic conditions does anaerobic digestion lead to the significant degradation of 1-AS . The use of anaerobic treatment followed by aerobic treatment did not improve degradation . Indeed aerobic post-treatment resulted in the re-appearance of pollutant in the medium even though this had been partly degraded under anaerobic conditions.

J Bacteriol, 1996 Jun, 178(12), 3496 - 500
In situ visualization of high genetic diversity in a natural microbial community; Amann R et al.; Simultaneous in situ visualization of seven distinct bacterial genotypes, all affiliated with the phylogenetically narrow group of beta-1 Proteobacteria, was achieved in activated sludge . This finding indicates that the high diversity found in the same sample by direct rRNA sequence retrieval was indeed present in this complex community . By the combination of comparative rRNA sequence analysis, in situ hybridization with fluorescently labeled, rRNA-targeted oligonucleotides and confocal laser scanning microscopy several microbial populations can be analyzed for abundance, relative spatial distribution and phylogeny directly at their site of action without prior cultivation.

Lett Appl Microbiol, 1996 May, 22(5), 342 - 6
The opportunistic pathogen Nocardia farcinica is a foam-producing bacterium in activated sludge plants; Stratton HM et al.; A Gram-positive unicellular coccal-diphtheroid rod causing foam in an activated sludge plant was successfully isolated by micromanipulation . Phenotypic characterization and 16S rDNA sequencing identified it as Nocardia farcinica . This is the first report that this opportunistic pathogen is a foam-causing bacterium in activated sludge, and the clinical implications of these observations are discussed.

Ecotoxicol Environ Saf, 1996 Apr, 33(3), 261 - 7
Preadapted inocula for limiting the risk of errors in biodegradability tests; Thouand G et al.; Reducing the time for biodegradability tests to 28 days poses a problem when the inoculum contains few biodegraders, as a biodegradable xenobiotic must give a positive result within this time . The influence of initial concentration (X0, number of cells liter-1) on the lag time (hours) of para-nitrophenol biodegradability tests was examined using different concentrations of adapted Pseudomonas putida with para-nitrophenol as the sole carbon and energy source . Lag time decreased as bacterial density increased according to the expression y = 63.5 - 5.7(log10X0) . The addition of river water to the P . putida concentrations shortened the lag time-bacterial density relationship and lag time filled the expression y = 52.4 - 5.1(log10X0) . The addition of river water also increased the rate of para-nitrophenol biodegradation from 1.29 mgC (liters x hr)-1 to 2.11 mgC (liters x hr)-1 . An examination of the effect of the initial adapted P . putida density, expressed as total cell, cultivable bacteria, or biodegraders, was also made on the para-nitrophenol biodegradability test outcome . The model-related cell density and the probability of test response give very similar k constants (kT = 0.56 x 10(-3) liter total cells-1; kv = 0.11 x 10(-3) liter CFU-1, kMPN = 0.16 x 10(-3) liter MPN-1) . Comparisons with nonadapted natural mixed culture (activated sludge, river water) indicate that the biodegradability test responses were the same as with adapted cells when the nonadapted cell concentrations were at least 5 x 10(10) total cells liter-1 . As this high cell concentration led to carbon contamination, adapting mixed inocula before the test to increase the number of biodegraders appears to be the best solution . Before biodegradability tests, cell density can be adjusted using techniques which are not specific to biodegraders, and only 10(5) total adapted cells liter-1 are needed for a 99.9% chance of a positive response in para-nitrophenol biodegradability tests.

Appl Microbiol Biotechnol, 1996 Feb, 44(6), 823 - 30
Changes in the composition of extracellular polymeric substances in activated sludge during anaerobic storage; Nielsen PH et al.; Changes in the chemical composition of organic compounds in total activated sludge, activated sludge extracellular polymeric substances (EPS), and sludge bulk water during anaerobic storage (12 days) were studied . The background for the study was that anaerobic storage of activated sludge, which often takes place at wastewater treatment plants before dewatering, causes a deterioration of the dewaterability . The reasons are not known at present, but may be related to changes in exopolymer composition of the flocs . The results showed that a fast decrease in total sludge protein and carbohydrate took place within 3 days of anaerobic storage as a result of degradation processes, which accounted for approximately 20% of the organic fraction . The amount of uronic acids and humic compounds remained almost constant in the sludge . The EPS were extracted from the floc matrix using a cation-exchange resin . In the EPS matrix a similar initial (2-3 days) degradation of proteins and carbohydrate took place, whereas the content of DNA and uronic acids showed minor changes . The extractability of humic compounds increased during the first 3 days of storage . No changes in extractability of the carbohydrate were observed . A fraction of the EPS protein was found to be difficult to extract but was observed to be degraded during the anaerobic storage . The EPS composition was further characterized by high-performance size-exclusion chromatography analysis obtained by on-line UV detection and post-column detection of proteins, carbohydrates, humic compounds and DNA . Four fractions of polysaccharides were found, of which only one was responsible for the decrease in the carbohydrate content observed with storage time . The fraction was presumably of low molecular mass . Humic compounds and volatile fatty acids (acetate and propionate) were released to the bulk water from the flocs during the storage . A possible mechanism to explain the reduced dewaterability developed during anaerobic storage, partly because of the observed changes in EPS, is discussed.

Microsc Res Tech, 1996 Jan 1, 33(1), 12 - 22
Ciliates in rapid gravity filters of waterworks exploiting deep groundwaters; Foissner W; Potable water is increasingly produced from deep (>100 m) tertiary groundwaters which often are completely reduced and contain high amounts of ammonium, methane, and hydrogen sulphide . They thus require special treatment which includes oxygenation and removal of the reduced contaminants by the biofilm developing in rapid gravity filters . The biofilm is heavily colonized with ciliates and microinvertebrates . A total of 38 species of ciliates was found in 42 samples taken from 4 waterworks in Germany during a period of 2 years . Only six species occurred in high numbers and in more than half of the samples: Acineria uncinata, Aspidisca lynceus, Cinetochilum margaritaceum, Colpidium colpoda, Glaucoma scintillans, and Holosticha pullaster . Five to thirteen species occurred per sample, and up to 6,000 individuals ml-1 biofilm were counted . There was a considerable fluctuation in the number of species and individuals, which could not be related to specific process parameters . The number of species and individuals decreased markedly from the filter surface to its centre . Colonization of the filters very likely occurs randomly via impure surface waters . The ciliate communities found consist mainly of alphamesosaprobic to polysaprobic species and thus closely resemble those known from activated-sludge processes . This is explained by the specific conditions near and in the biofilm, which is probably microaerobic and highly productive, providing microaerobic bacterial feeders with copious food . Obviously, it is the microenvironment which determines the occurrence of certain species . Thus, future research on the autecology of the indicator species used in the saprobic system should concentrate on their microenvironments.

Appl Biochem Biotechnol, 1996 Spring, 57-58, 851 - 6
Filamentous growth in activated sludge; Chua H et al.; Bulking and foaming in activated sludge have been associated with filamentous overgrowth . Filamentous Nocardia amarae and nonfilamentous Pseudomonas auruginosa were cultured using fatty acids (C2-C24) as the sole carbon . N . amarae could utilize all acids tested for growth, whereas P . auruginosa hardly grew on acids with 12 or more carbons . Maximum specific growth rate and saturation constant of N . amarae on C24, at 0.048 h-1 and 1.520 g COD/L, respectively, were much lower than that of P . auruginosa, showing that N . amarae had a relatively stronger affinity for long-chain fatty acids . N . amarae was competitive in activated sludge processes that receive sewage containing a high proportion of long-chain fatty acids, oils, and fats.

Appl Microbiol Biotechnol, 1995 Dec, 44(3-4), 532 - 8
Bacterial degradation of glycol ethers; Kawai F; Assimilation of ethyleneglycol (EG) ethers by polyethyleneglycol-utilizing bacteria was examined . Ethyleneglycol ether-utilizing bacteria were also isolated from soil and activated sludge samples by enrichment-culture techniques . Three strains (4-5-3, EC 1-2-1 and MC 2-2-1) were selected and characterized as Pseudomonas sp . 4-5-3, Xanthobacter autotrophicus, and an unidentified gram-negative, non-spore-forming rod respectively . Their growth characteristics were examined: Pseudomonas sp . 4-5-3 assimilated EG (diethyleneglycol, DEG) monomethyl, monoethyl and monobutyl ethers, DEG, propanol and butanol . X . autotrophicus EC 1-2-1 grew well on EG monoethyl and monobutyl ethers, EG and primary alcohols (C1-C4), and slightly on EG monomethyl ether . The strain MC 2-2-1 grew on EG monomethyl ether, EG, primary alcohols (C1-C4), and 1,2-propyleneglycol (PG) . The mixed culture of Pseudomonas sp . 4-5-3 and X . autotrophicus EC 1-2-1 showed better growth and improved degradation than respective single cultures towards EG monomethyl, monoethyl or monobutyl ethers . Intact cells of Pseudomonas sp . 4-5-3 degraded various kinds of monoalkyl ethers, which cannot be assimilated by the strain . Metabolic products were characterized from reaction supernatants of intact cells of Pseudomonas sp . 4-5-3 with EG or DEG monoethyl ethers: they were analyzed by thin-layer chromatography and GC-MS and found to be ethoxyacetic acid and ethoxyglycoxyacetic acid . Also, PG monoalkyl ethers (C1-C4), dipropyleneglycol monoethyl and monomethyl ethers and tripropyleneglycol monomethyl ether were assimilated by polypropyleneglycol-utilizing Corynebacterium sp . 7.

FEMS Microbiol Lett, 1995 Nov 15, 133(3), 277 - 83
Identification of a 13-kDa protein associated with the polyhydroxyalkanoic acid granules from Acinetobacter spp; Schembri MA et al.; Proteins associated with poly-beta-hydroxybutyrate (PHB) granules were purified from four Acinetobacter strains isolated from modified activated sludge treatment plants . Four predominant proteins of 64 kDa, 41 kDa, 38 kDa and 13 kDa were identified . N-terminal amino acid sequencing of the 64-kDa and 13-kDa proteins from Acinetobacter RA3849 identified these proteins as the products of the phaCAc and phaPAc (formerly designated ORF1) genes, respectively . The expression of the 13-kDa protein (referred to as GA13) is shown to be required for the accumulation of large amounts of PHB in a recombinant Escherichia coli strain.

Appl Environ Microbiol, 1995 Nov, 61(11), 3981 - 5
Application of reverse transcriptase PCR for monitoring expression of the catabolic dmpN gene in a phenol-degrading sequencing batch reactor; Selvaratnam S et al.; A modified freeze-thaw method in combination with reverse transcriptase PCR was developed for monitoring gene expression in activated sludge . The sensitivity of the methodology was determined by inoculating non-sterile activated sludge samples with 3-chlorobenzoate-degrading Pseudomonas putida PPO301(pRO103), which contains the catabolic tfdB gene . tfdB mRNA was detected in 10 mg of activated sludge inoculated with 10(4) CFU of the target organism . This technique was subsequently utilized to analyze the in situ expression of the catabolic dmpN gene in a sequencing batch reactor (SBR) bioaugmented with phenol-degrading P . putida ATCC 11172 . Greatest dmpN expression was observed 15 min after maximum phenol concentration was reached in the reactor and 15 min after the start of aeration . Decreased phenol concentrations in the reactor corresponded to reduced levels of dmpN expression, although low levels of dmpN mRNA were observed throughout the SBR cycle . These results indicate that concentration of phenol in the reactor and the onset of aeration stimulated transcriptional activity of the dmpN gene . The information obtained from this study can be used to alter SBR operational strategies so as to lead to more effective bioaugmentation practices.

Lett Appl Microbiol, 1995 Sep, 21(3), 207 - 9
Detection of coliphages and enteroviruses in sewage and aerosol from an activated sludge wastewater treatment plant; Carducci A et al.; Coliphages and enteroviruses were monitored over 12 months in sewage and air adjacent to an activated sludge plant . Both showed temporal variation but the mean count of phages in enterovirus-positive samples was not significantly different from that in enterovirus-negative samples . Hence coliphages are not necessarily a good indicator of enteroviruses in sewage and aerosols.

J Bacteriol, 1995 Aug, 177(15), 4501 - 7
Phosphate concentration regulates transcription of the Acinetobacter polyhydroxyalkanoic acid biosynthetic genes; Schembri MA et al.; The polyhydroxyalkanoic acid (PHA) biosynthetic gene locus was cloned and characterized from an Acinetobacter sp . isolated from activated sludge . Nucleotide sequence analysis identified three clustered genes, phaAAc (encoding a beta-ketothiolase), phaBAc (encoding an acetoacetyl coenzyme A reductase), and phaCAc (encoding a PHA synthase) . In addition, an open reading frame (ORF1) with potential to encode a 13-kDa protein was identified within this locus . The sequence of the putative translational product of ORF1 does not show significant similarity to any sequences in the database . A plasmid containing the Acinetobacter pha locus conferred the ability to accumulate poly-beta-hydroxybutyrate on its Escherichia coli host . These genes appear to lie in an operon transcribed by two promoters upstream of phaBAc, an apparent constitutive promoter, and a second promoter induced by phosphate starvation and under pho regulon control . These as well as a number of additional potential transcription start points were identified by a combination of primer extension and promoter-chloramphenicol acetyltransferase gene fusion studies carried out in Acinetobacter or E . coli transformants.

Appl Microbiol Biotechnol, 1995 Aug-Sep, 43(4), 755 - 61
Enzymatic activity in the activated-sludge floc matrix; Frolund B et al.; The enzymatic activity of activated sludge was investigated with special emphasis on the localization of the enzymes in the sludge floc matrix . Activated sludge from an advanced activated-sludge treatment plant, performing biological N and P removal, was used . An enzymatic fingerprint was established using a panel of six different enzymes . The fingerprint revealed peptidase as the most dominating specific enzyme tested . By monitoring sludge bulk enzymatic activity over a 3-month period using fluorescein diacetate as an enzyme substrate, considerable variations in activity were observed even over short periods (a few days) . The variation in esterase activity was to some extent correlated to the presence of humic compounds in the sludge, but not to the sludge protein content . Comparison of full sludge enzyme activity to the activity of a batch-grown sludge culture indicated that enzymes accumulated in sludge flocs . A large proportion of the exoenzymes were immobilized in the sludge by adsorption in the extracellular polymeric substances (EPS) matrix . This was demonstrated by extraction of EPS from the activated sludge using cation exchange . Contemporary to the release of EPS a very large fraction of the exoenzymes was released into the water . This showed that the exoenzymes should be considered to be an integrated part of the EPS matrix rather than as direct indicators of the microbial activity or biomass.

Ecotoxicol Environ Saf, 1995 Aug, 31(3), 218 - 23
Influence of the size and source of the inoculum on biodegradation curves in closed-bottle tests; van Ginkel CG et al.; Test variables influencing the results of the closed-bottle test include size and source of the inoculum . The inoculum originates from activated sludge plants maintained at various sludge retention times . The lag period prior to biodegradation, which is influenced primarily by acclimation, decreased with increasing numbers of competent microorganisms . The rate of biodegradation in the closed-bottle test is influenced by the sludge retention time by which the inocula are maintained . Acclimated sludges maintained at low sludge retention times used as inocula gave biodegradation curves with steep slopes, indicating degradation at high rates . Therefore, unacclimated ready biodegradability tests enable only conservative assessments of the biodegradation potential of wastewater purification plants . The results reported here demonstrate that other tests should be used in risk assessment to estimate the full biodegradation potential in wastewater treatment plants.

J Ind Microbiol, 1995 Jul, 15(1), 19 - 24
Phosphate uptake by immobilized Acinetobacter calcoaceticus cells in a full scale activated sludge plant; Muyima NY et al.; An in situ study of the P-uptake ability of Acinetobacter calcoaceticus was carried out using the alginate immobilization technique . Immobilized A . calcoaceticus cells displayed a high P-uptake ability (> 97% P-accumulating cells) when immersed in the aerobic zone of an activated sludge system for 30-240 min . The overall P-accumulation pattern of the anaerobic zone depicted a typical P-release mechanism . However, limited P-accumulation was also observed at this stage . Growth and anaerobiosis were not prerequisites for P-uptake . The immobilized cell retention time in the anaerobic zone did not affect remarkably the inherent P-uptake ability of immobilized A . calcoaceticus when exposed to the aerobic stage . P-uptake and release were reversible and depended on the environmental conditions to which immobilized cells were exposed . Immobilization of A . calcoaceticus using alginate can be regarded as a reliable method of studying pure cultures in the activated sludge process.

Biodegradation, 1995 Jun, 6(2), 83 - 92
Degradation of 4-chloro-2-methylphenol by an activated sludge isolate and its taxonomic description; Lechner U et al.; The Gram-negative strain S1, isolated from activated sludge, metabolized 4-chloro-2-methylphenol by an inducible pathway via a modified ortho-cleavage route as indicated by a transiently secreted intermediate, identified as 2-methyl-4-carboxymethylenebut-2-en-4-olide by gas chromatography/mass spectrometry . Beside 4-chloro-2-methylphenol only 2,4-dichlorophenol and 4-chlorophenol were totally degraded, without an accumulation of intermediates . The chlorinated phenols tested induced activities of 2,4-dichlorophenol hydroxylase and catechol 1,2-dioxygenase type II . Phenol itself appeared to be degraded more efficiently via a separate, inducible ortho-cleavage pathway . The strain was characterized with respect to its physiological and chemotaxonomic properties . The fatty acid profile, the presence of spermidine as main polyamine, and of ubiquinone Q-10 allowed the allocation of the strain into the alpha-2 subclass of the Proteobacteria . Ochrobactrum anthropi was indicated by fatty acid analysis as the most similar organism, however, differences in a number of physiological features (e.g . absence of nitrate reduction) and pattern of soluble proteins distinguished strain S1 from this species.

Chemosphere, 1995 Jun, 30(11), 2209 - 17
Biodegradation of toluene diamine (TDA) in activated sludge acclimated with aniline and TDA; Asakura S et al.; The biodegradability of toluene diamine (TDA) which has been regarded as a "recalcitrant compound" was examined in activated sludges . In this study, a microorganic-enzyme system which metabolized TDA was obtained by acclimating the activated sludge with aniline and TDA . In the sludge subject to be 200 days' acclimation, the considerable increase in respiration rate with the addition of TDA, accompanied the sharp decrease in its concentration . This indicated that TDA was metabolized fortuitously . The rate of biodegradation of TDA in the absence of aniline was first order with respect to its concentration when the initial TDA concentration was less than about 5 mg/l . The rate constant in this relation was proportional to mixed liquor suspended solid (MLSS) . However, when the initial TDA concentration exceeded 5 mg/l, the plots were deviated from a first order rate equation.

Appl Environ Microbiol, 1995 May, 61(5), 1859 - 66
Flow cytometric analysis of activated sludge with rRNA-targeted probes; Wallner G et al.; Samples from a wastewater treatment plant were hybridized with fluorescein-labeled oligonucleotide probes specific for members of the domains Bacteria and Eucarya; the alpha, beta, and gamma subclasses of the class Proteobacteria; or the genus Acinetobacter . Subsequently, they were counterstained with the DNA-specific dye Hoechst 33342 and analyzed by flow cytometry . By quantifying forward angle light scatter and Hoechst- and probe-conferred fluorescence as measures for cell size, DNA content, and rRNA content, respectively, not only relative abundances but also assessments of general metabolic activity for each of these groups were obtained . Hybridizations with a positive control probe binding to all bacteria showed that in the activated-sludge samples examined, 70 to 80% of the Hoechst-stained cells could unambiguously be identified by this method . The majority of the detected cells (approximately 40%) were beta-subclass Proteobacteria . Flow cytometric and microscopic counts were in general agreement . Discrepancies were found in particular for those populations that occurred predominantly in flocs (alpha subclass of the Proteobacteria) or chains (Acinetobacter spp.) . Although the dispersal of aggregates needs to be improved, flow cytometry combined with rRNA-based in situ probing appears to be a powerful tool for the rapid and highly automated analysis of the microbial communities in activated sludge.

Appl Environ Microbiol, 1995 May, 61(5), 1910 - 6
Bacterial community structures of phosphate-removing and non-phosphate-removing activated sludges from sequencing batch reactors; Bond PL et al.; The bacterial community structures of phosphate- and non-phosphate-removing activated sludges were compared . Sludge samples were obtained from two sequencing batch reactors (SBRs), and 16S rDNA clone libraries of the bacterial sludge populations were established . Community structures were determined by phylogenetic analyses of 97 and 92 partial clone sequences from SBR1 (phosphate-removing sludge) and SBR2 (non-phosphate-removing sludge), respectively . For both sludges, the predominant bacterial group with which clones were affiliated was the beta subclass of the proteobacteria . Other major groups represented were the alpha proteobacterial subclass, planctomycete group, and Flexibacter-Cytophaga-Bacteroides group . In addition, several clone groups unaffiliated with known bacterial assemblages were identified in the clone libraries . Acinetobacter spp., thought to be important in phosphate removal in activated sludge, were poorly represented by clone sequences in both libraries . Differences in community structure were observed between the phosphate- and non-phosphate-removing sludges; in particular, the Rhodocyclus group within the beta subclass was represented to a greater extent in the phosphate-removing community . Such differences may account for the differing phosphate-removing capabilities of the two activated sludge communities.

Appl Microbiol Biotechnol, 1995 Apr, 43(1), 143 - 9
Biodegradation of 2-chloroethanol by freely suspended and adsorbed immobilized Pseudomonas putida US2 in soil; Overmeyer C et al.; The degradation of 2-chloroethanol by Pseudomonas putida US2 was investigated in batch, repeated batch and continuous cultures especially in a packed-bed fermenter with sand . The degradation of 2-chloroethanol was connected with a release of protons, which led to a decrease of the pH in the medium . Higher initial concentration than 25 mM 2-chloroethanol were not degraded completely because they entailed a decrease of the pH to 5.0, which inhibited further growth and degradation . P . putida US2 showed a typical repression of catabolites and diauxic growth with succinate as cosubstrate . The addition of succinate as a second substrate caused a decrease in degradation of 2-chloroethanol . Activated sludge added to adsorbed cultures in a continuous fermentation did not lead to a decrease in metabolic activity . After 2 weeks of continuous cultivation the specialized strain could be retained.

Appl Microbiol Biotechnol, 1995 Mar, 42(6), 951 - 7
Biodegradation of chlorophenols by mixed and pure cultures from a fluidized-bed reactor; Puhakka JA et al.; An aerobic, continuous-flow fluidized-bed reactor was established with inoculum from activated sludge, and fed a mixture of 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol (TeCP) and pentachlorophenol (PCP) as the sole sources of carbon and energy for 2 years . Experiments with the enrichment were performed with material from the reactor . Later, degradation experiments were completed using pure cultures of bacteria that were isolated from suspended samples of the carrier biofilm . In batch-bottle bioassays, the reactor enrichment degraded PCP, TeCP and TCP both in mineral salts (MS) and tryptone-yeast extract-glucose (TGY) media . ortho-Methoxylated chlorophenols including 4,5-dichloroguaiacol (4,5-DCG), tetrachloroguaiacol (TeCG) and trichlorosyringol (TCS) resisted biodegradation by the enrichment both in MS and TGY media, whereas 5,6-dichlorovanillin (5,6-DCV) was readily transformed to an unidentified metabolite . Experiments with 14C labeled chlorophenols showed mineralization of 2,4-dichlorophenol (DCP) and 2,3,5-TCP to 14CO2 by the enrichment . Material from the suspended biofilm after continuous chlorophenol feeding for 2 years was inoculated onto TGY-agar plates, and showed predominantly two colony types accounting for over 99% of the total colony counts . The two colony types, were equal in abundance . Six Gram-negative, oxidase- and catalase-positive, nonfermentative small rods were isolated in TGY agar media supplemented with 10 mg/l of TeCP or PCP . All isolates formed colonies in TGY plus 150 mg/l of PCP . The isolates degraded TCP and TeCP but not PCP . In mixtures of isolated bacteria the rates of chlorophenol degradation were similar to those observed with individual isolates . Three isolates were identified as Pseudomonas saccharophila and three were an unidentified species of Pseudomonas.

Microbiology, 1995 Mar, 141 ( Pt 3), 721 - 5
Carbon-arsenic bond cleavage by a newly isolated gram-negative bacterium, strain ASV2; Quinn JP et al.; Strain ASV2, an unidentified Gram-negative bacterium newly isolated from activated sludge, was found to utilize arsonoacetate at concentrations up to at least 30 mM as sole carbon and energy source, with essentially quantitative extracellular release of arsenate . Cell-free conversion of arsonoacetate could not be obtained, but resting-cell studies indicated that the carbon-arsenic bond cleavage activity was inducible in the presence of arsonoacetate and was of limited substrate specificity, also breaking down arsonochloroacetate . The inorganic product of the reaction may be arsenite since an inducible arsenite-oxidizing activity was also found in arsonoacetate-metabolizing cells . This is the first report of a micro-organism capable of utilizing a compound containing the carbon-arsenic bond . The results indicate that the ability of bacteria to degrade arsonoacetate is not fortuitous and may be found in environments not previously exposed to organoarsenicals.

Microbiol Rev, 1995 Mar, 59(1), 143 - 69
Phylogenetic identification and in situ detection of individual microbial cells without cultivation; Amann RI et al.; The frequent discrepancy between direct microscopic counts and numbers of culturable bacteria from environmental samples is just one of several indications that we currently know only a minor part of the diversity of microorganisms in nature . A combination of direct retrieval of rRNA sequences and whole-cell oligonucleotide probing can be used to detect specific rRNA sequences of uncultured bacteria in natural samples and to microscopically identify individual cells . Studies have been performed with microbial assemblages of various complexities ranging from simple two-component bacterial endosymbiotic associations to multispecies enrichments containing magnetotactic bacteria to highly complex marine and soil communities . Phylogenetic analysis of the retrieved rRNA sequence of an uncultured microorganism reveals its closest culturable relatives and may, together with information on the physicochemical conditions of its natural habitat, facilitate more directed cultivation attempts . For the analysis of complex communities such as multispecies biofilms and activated-sludge flocs, a different approach has proven advantageous . Sets of probes specific to different taxonomic levels are applied consecutively beginning with the more general and ending with the more specific (a hierarchical top-to-bottom approach), thereby generating increasingly precise information on the structure of the community . Not only do rRNA-targeted whole-cell hybridizations yield data on cell morphology, specific cell counts, and in situ distributions of defined phylogenetic groups, but also the strength of the hybridization signal reflects the cellular rRNA content of individual cells . From the signal strength conferred by a specific probe, in situ growth rates and activities of individual cells might be estimated for known species . In many ecosystems, low cellular rRNA content and/or limited cell permeability, combined with background fluorescence, hinders in situ identification of autochthonous populations . Approaches to circumvent these problems are discussed in detail.

Acta Microbiol Pol, 1995, 44(2), 171 - 9
Isolation and identification of bacteria from activated sludge purifying petroleum wastewaters; Bieszkiewicz E et al.; Several strains growing well in minimal media with 500 and 1000 mg/l of oil or phenol as a sole carbon source were isolated from activated sludge purifying petroleum waste waters and identified . Five of the best growing strains classified as Arthrobacter, Pseudomonas, Xanthomonas and Enterobacter were selected and their capacity to remove petroleum components and phenol (in the oil fraction of petrochemical waste waters) was studied . The enzymatic activity of the strains, including respiration intensity and dehydrogenase activity was also determined . All the examined strains were found to use oils as the sole source of carbon (percent age of the oils reduction during cultivation of the individual strains ranged from 58 to 78) . Phenol was completely reduced by only one strain . The rest of the strain removed only from 7 to 24% of this compound . The activity of dehydrogenases and the respiration intensity in the presence of the studied substrates -- oil and phenol was low for all the examined strains.

Int J Syst Bacteriol, 1995 Jan, 45(1), 17 - 22
Microlunatus phosphovorus gen . nov., sp . nov., a new gram-positive polyphosphate-accumulating bacterium isolated from activated sludge; Nakamura K et al.; Polyphosphate-accumulating bacteria that were previously isolated from activated sludge and exhibited high phosphate removal activity were studied taxonomically and phylogenetically . These organisms were gram-positive, coccus-shaped, aerobic chemoorganotrophs that had a strictly respiratory type of metabolism in which oxygen was a terminal electron acceptor . They accumulated large amounts of polyphosphate under aerobic conditions . The major quinone was menaquinone MK-9(H4) . The cell wall peptidoglycan contained LL-diaminopimelic acid . The guanine-plus-cytosine content of the DNA was 67.9 mol% . Our isolates were similar phenotypically and chemotaxonomically to Luteococcus japonicus, which was proposed recently as a new genus and species . However, our isolates differed from L . japonicus in cellular fatty acid composition and some other traits . A phylogenetic analysis based on 16S rRNA sequences showed that our isolate differ from the genus Luteococcus and other genera belonging to the high-G+C-content gram-positive group . Accordingly, we concluded that our strain NM-1T (T = type strain) should be assigned to a new genus and species, for which we propose the name Microlunatus phosphovorus.

Microbiology, 1994 Oct, 140 ( Pt 10), 2849 - 58
In situ probing of gram-positive bacteria with high DNA G + C content using 23S rRNA-targeted oligonucleotides; Roller C et al.; 23S-rRNA-targeted oligonucleotide probes were designed for the phylogenetic group 'Gram-positive bacteria with high G + C content of DNA' (GPBHGC) . A sequence idiosyncrasy in two adjacent base pairs in the stem of helix 69 in domain IV of the 23S rRNA is present in all hitherto analysed strains of GPBHGC . An oligonucleotide probe targeted to this region hybridized only with strains of GPBHGC and was successfully used for in situ monitoring of these cells in activated sludge . Another unique feature of the 23S rRNA molecules of GPBHGC is a large insertion in domain III . Fluorescent oligonucleotides targeted to the highly variable regions of the rRNA within the insertions of Corynebacterium glutamicum DSM 20300, Aureobacterium testaceum DSM 20166 and Brevibacterium sp . DSM 20165 hybridized specifically to their target strains, whereas probing with oligonucleotides complementary to the rRNA-coding strand of the 23S rDNA and to the spacer between 16S and 23S rRNA of C . glutamicum did not result in detectable fluorescence . This confirmed that the large 23S insertions are indeed present in 23S rRNAs of GPBHGC and provide potential target sites for highly specific nucleic acid probes.

Appl Microbiol Biotechnol, 1994 Oct, 42(1), 134 - 9
Metabolism of dodecyldimethylamine by Pseudomonas MA3; Kroon AG et al.; Pseudomonas MA3 was isolated from activated sludge on the basis of its capacity to use dodecyldimethylamine as a sole carbon (C) and energy source . Dodecylamine, dodecanal, dodecanoic acid and acetic acid also supported growth of Pseudomonas MA3 . Dodecyldimethylamine-grown cells oxidized a wide range of alkylamine derivatives, dodecanal, dodecanoic acid and acetic acid . Degradation of the alkyl chain of dodecyldimethylamine by Pseudomonas MA3 appeared from the stoichiometric liberation of dimethylamine . A dehydrogenase catalysed the cleavage of the Calkyl-N bond . The first intermediate of the proposed degradation pathway, dodecanal, accumulated in the presence of decanal used as a competitive inhibitor . The second intermediate, dodecanoic acid, was formed in the presence of acrylic acid during the degradation of dodecyldimethylamine . Dodecanal was converted into dodecanoic acid by a dehydrogenase and dodecanoic acid was then degraded via the beta oxidation pathway.

Biosci Biotechnol Biochem, 1994 Sep, 58(9), 1589 - 94
Production of a bioflocculant by mixed culture; Kurane R et al.; Colony groups that form large amounts of slime externally were obtained from activated sludge among phthalate-assimilating microbes . That slime, which R-3 mixed microbes produced externally, had a high level of flocculation activity . R-3 mixed strains, one of such colony groups, efficiently produced a bioflocculant (APR-3) in liquid cultures of production medium, especially that containing starch and glucose (1:1) as carbon sources . Identification of this group of bioflocculant-producing microbes (R-3 mixed strains) showed that it was comprised of four strains belonging to the genera Oerskovia, Acinetobacter, Agrobacterium, and Enterobacter . The bioflocculant (APR-3) was purified electrophoretically to homogeneity by ethanol and CPC precipitation . Its molecular mass is at least 2 x 10(6) Da . APR-3 is an acidic polysaccharide made of glucose, galactose, succinic acid, and pyruvic acid (molar ratio: 5.6:1:0.6:2.5).

Chemosphere, 1994 Jul, 29(1), 81 - 8
Utilization of 2-phosphonobutane-1,2,4-tricarboxylic acid as source of phosphorus by environmental bacterial isolates; Raschke H et al.; Six bacterial strains able to degrade aerobically 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) were isolated . The bacteria used PBTC as sole source of phosphorus in the presence of an alternative source of carbon . The microorganisms were taken from various ecosystems, e.g . river water, river sediment and activated sludge . PBTC up to a concentration of 1 mM (270 mg/l) was completely degraded by a defined mixed culture.

FEMS Microbiol Lett, 1994 May 1, 118(1-2), 145 - 52
Cloning and analysis of the polyhydroxyalkanoic acid synthase gene from an Acinetobacter sp.: evidence that the gene is both plasmid and chromosomally located; Schembri MA et al.; The polyhydroxyalkanoic acid (PHA) synthase gene (phaCAc) of a species of Acinetobacter isolated from an activated sludge treatment plant was cloned by heterologous complementation in a poly-beta-hydroxybutyrate (PHB) negative mutant of Alcaligenes eutrophus . Nucleotide sequence analysis of phaCAc revealed an open reading frame of 1770 bp with potential to encode a 67.7 kDa protein . The deduced amino acid sequence displays high similarity to other PHA synthase proteins . Probing with an internal region of phaCAc revealed that the PHA synthase gene may be present in more than one copy and may occur at both plasmid and chromosomal locations in Acinetobacter spp . This is the first organism for which evidence has been presented to suggest that a gene involved in PHA metabolism is plasmid-encoded . Purification of PHB granules from sucrose gradients identified proteins of 38 kDa, 41 kDa and 64 kDa which may have a role in PHB metabolism.

J Gen Microbiol, 1993 Nov, 139 ( Pt 11), 2695 - 703
Conservation of regulatory and structural genes for a multi-component phenol hydroxylase within phenol-catabolizing bacteria that utilize a meta-cleavage pathway; Nordlund I et al.; Pseudomonas sp . strain CF600 can degrade phenol and some of its methylated derivatives via a plasmid (pVI150)-encoded pathway . The metabolic route involves hydroxylation by a multi-component phenol hydroxylase and a subsequent meta-cleavage pathway . All 15 structural genes involved are clustered in an operon that is regulated by a divergently transcribed transcriptional activator . The multi-component nature of the phenol hydroxylase is unusual since reactions of this type are usually accomplished by single component flavoproteins . We have isolated and analysed a number of marine bacterial isolates capable of degrading phenol and a range of other aromatic compounds as sole carbon and energy sources . Southern hybridization and enzyme assays were used to compare the catabolic pathways of these strains and of the archetypal phenol-degrader Pseudomonas U, with respect to known catabolic genes encoded by Pseudomonas CF600 . All the strains tested that degraded phenol via a meta-cleavage pathway were found to have DNA highly homologous to each of the components of the multicomponent phenol hydroxylase . Moreover, DNA of the same strains also strongly hybridized to probes specific for pVI150-encoded meta-pathway genes and the specific regulator of its catabolic operon . These results demonstrate conservation of structural and regulatory genes involved in aromatic catabolism within strains isolated from diverse geographical locations (UK, Norway and USA) and a range of habitats that include activated sludge, sea water and fresh-water mud.

Zentralbl Hyg Umweltmed, 1993 Sep, 194(5-6), 481 - 9
Virucidal activity of an activated sludge supernatant; Rehn Y et al.; The virucidal activity of the activated sludge aqueous phase was studied from the time of initial inoculation with a poliovirus type 1 suspension and for durations of three and nine days . The mixtures were incubated in presence of a nutritive medium at 26 degrees C and samples were drawn at regular intervals of time for viral titration . The activated sludge supernatant (ASS) caused an important decrease of the titer of the poliovirus type 1 suspension especially after nine days of incubation . There was an average reduction of the viral titer of 79% after three days and 97% after nine days . When incubating the ASS with a nutritive medium before inoculating it, the viral decrease was much greater than when incubating without nutritive medium . When sterilizing the ASS before incubation and then inoculating it, no significant virucidal activity was observed (0% to 6%) . Furthermore, when the ASS was subjected to a sterilization by filtration after incubation and was then inoculated, there existed a lower but not negligible viral inactivation (53% to 64%) . The virucidal activity potentiality of the ASS is therefore due to microorganisms acting both directly as a support for viral particles adsorption and indirectly via the synthesis of substances with virucidal activity . When freezing and thawing the incubated ASS, and then sterilizing it by filtration before inoculation, the viral decrease reached 87% to 94% . This proves that the virucidal substances are only partly excreted by the microorganisms.

Rev Latinoam Microbiol, 1993 Jul-Sep, 35(3), 281 - 8
{Isolation and selection of methylamines and dimethyl formamide degrading microorganisms}; Saval S et al.; From an activated sludge sample, microorganisms capable to degrade monomethylamine (MMA), dimethylamine (DMA), trimethylamine (TMA), and dimethylformamide (DMF) were isolated . These compounds are present in the wastewaters from a petrochemical plant . Microbial communities were cultivated, in aerobic conditions in a 2-liter bioreactor fed with the wastewater . Only four different kinds of microorganisms were obtained, but they could maintain their degradative capacity after several transfers . This microbial biomass was able to reduce 90% of the dissolved pollutants in a sample of industrial wastewater, mainly MMA, DMA, TMA, and DMF, measured as dissolved organic carbon, in approximately 5 days.

Appl Microbiol Biotechnol, 1993 Jul, 39(4-5), 622 - 6
Parameters affecting the degradation of benzothiazoles and benzimidazoles in activated sludge systems; De Vos D et al.; It was found that benzothiazole, 2-oxybenzothiazole and 2-benzothiazolesulphonate were degraded in activated sludge systems . 2-Mercaptobenzothiazole (MBT) was more resistant, although the first step in MBT degradation seemed to be transformation to the sulphonate form . At higher MBT concentrations, it was transformed into a disulphide, which accumulated in the sludge . MBT was also found to be mainly responsible for the toxicity of rubber chemical waste-water towards activated sludges . It inhibited the degradation of the other heterocycles . Only at concentrations of around 20 ppm was MBT degraded . Mercaptobenzimidazole ranked second in resistance to degradation.

J Ind Microbiol, 1993 Jul, 11(4), 243 - 52
Fate in sewage of a recombinant Escherichia coli K-12 strain used in the commercial production of bovine somatotropin; Heitkamp MA et al.; The fate of a derivative of Escherichia coli strain W3110G {pBGH1}, a strain used for production of bovine somatotropin, was examined in semi-continuous activated sludge (SCAS) units . A nalidixic acid-resistant derivative of W3110G {pBGH1}, strain LBB270 {pBGH1}, was used to facilitate tracking . SCAS units (300 ml) containing municipal mixed liquor were operated on a daily cycle of 23 h aeration and 1 h setting followed by decanting of clear supernatant (175 ml) and refilling with fresh primary effluent . SCAS units were inoculated with two concentrations of E . coli LBB270 {pBGH1} and operated for 200 h . Viable levels of E . coli LBB270 {pBGH1} were measured daily in aerated mixed liquor and decanted supernatant . Viable counts in the mixed liquor decreased from 10,000- to 100,000-fold in less than 200 h . Losses of E . coli LBB270 {pBGH1} in decanted supernatants accounted for less than 2-fold of the total losses observed in the SCAS units . The E . coli LBB270 {pBGH1} was not evenly distributed in the mixed liquor, but became preferentially associated with the settleable floc . These results show that E . coli LBB270 {pBGH1} was unable to survive in municipal sludge even when inoculated at concentrations greater than, or comparable to, levels of indigenous microorganisms.

J Ind Microbiol, 1993 Jul, 11(4), 217 - 22
Relationship between safety data and biocontainment design in the environmental assessment of fermentation organisms--an FDA perspective; Jones RA et al.; The Center for Veterinary Medicine requires strain/construct-specific data for recombinant fermentation organisms used in the production of animal drugs and feed additives . Fermentation plant biocontainment schemes are chosen based, in part, upon the ability of the organism to survive and persist in the environment and to transfer genetic information to indigenous organisms . Survival and persistence study methods may include one of the following ecosystems: activated sludge, mammalian gut, soil or river water . Gene transfer protocols can be incorporated into a persistence study . These studies are designed to show that the recombinant construct behaves similarly to the host in a representative ecosystem where the organism could be introduced inadvertently . The studies need to provide repeatable results and reflect current state-of-art design and methods . Data verification is conducted by FDA investigators during Good Laboratory Practice inspections . Biocontainment guidelines, such as those developed by the NIH Recombinant DNA Advisory Committee, set general biocontainment goals for large groupings of recombinant organisms . The FDA, as required under the National Environmental Policy Act, must base its decision making on verifiable scientific data specific to each application . Therefore, in addition to using these guidelines as benchmarks, sponsors are required to submit strain/construct-specific data to support the selection of an appropriate biocontainment level . Once additional well-controlled studies for a variety of constructs are available, broader generalizations as to biocontainment may be drawn.

Appl Environ Microbiol, 1993 May, 59(5), 1520 - 5
Probing activated sludge with oligonucleotides specific for proteobacteria: inadequacy of culture-dependent methods for describing microbial community structure; Wagner M et al.; Bacterial community structures in activated sludge samples from aeration tanks of a two-stage system with a high-load first stage and a low-load second stage were analyzed with oligonucleotide probes . The probes were complementary to conserved regions of the rRNA of the alpha, beta, and gamma subclasses of proteobacteria and of all bacteria . Group-specific cell counts were determined by in situ hybridization with fluorescent probe derivatives . Contributions of the proteobacterial subclasses to total bacterial rRNA were quantified by dot blot hybridization with digoxigenin-labeled oligonucleotides . The activated sludge samples were dominated by proteobacteria from the alpha, beta, or gamma subclass . These proteobacteria account for about 80% of all active bacteria found in the activated sludge . For both samples the community structures determined with molecular techniques were compared with the composition of the heterotrophic saprophyte flora isolated on nutrient-rich medium . Probes were used to rapidly classify the isolates and to directly monitor population shifts in nutrient-amended, activated sludge samples . The rich medium favored growth of gamma-subclass proteobacteria (e.g., enterobacteria) and selected against beta-subclass proteobacteria . The culture-dependent community structure analysis of activated sludge produced partial and heavily biased results . A more realistic view will be obtained by using in situ techniques.

Food Chem Toxicol, 1993 May, 31(5), 351 - 5
Absorption and accumulation of cadmium, lead and mercury from foods by rats; Yannai S et al.; The purpose of this study was to estimate the apparent absorbability of cadmium (Cd), lead (Pb) and mercury (Hg) from different foods by young rats when these elements occur intrinsically . The study consisted of three independent experiments . In the first experiment rats were fed a casein control diet, a corn-silage diet or an activated-sludge diet . Although the amount of Cd, Pb and Hg ingested from the sludge diet was orders of magnitude higher than that from the casein or corn-silage diet, the absorption of the metals was significantly less (P < 0.02) because these were present as poorly-soluble phosphates . In the second experiment, rats were fed either a commercial fish-meal control diet or an experimental fish-meal diet, with or without the addition of sodium phytate, based on catches from metal-polluted waters . No reduction in absorption resulted from the diet containing phytate as compared with the diet without phytate . The third experiment used the radioactive tracers Cd-115m, Pb-210 and Hg-203 intrinsically incorporated individually into maturing corn ears, on which the three experimental diets were based . The liver and kidney were the main target organs for all three elements (liver: Cd 0.6%, Pb 1.4% and Hg 0.6%; kidney: Cd 0.8%, Pb 0.9% and Hg 1.3%).

Appl Environ Microbiol, 1993 Apr, 59(4), 1220 - 7
Degradation of poly(3-hydroxyoctanoic acid) {P(3HO)} by bacteria: purification and properties of a P(3HO) depolymerase from Pseudomonas fluorescens GK13; Schirmer A et al.; Twenty-five gram-negative bacteria and one gram-positive bacterium capable of growing on poly(3-hydroxyoctanoic acid) {P(3HO)} as the sole source of carbon and energy were isolated from various soils, lake water, and activated sludge . Most of the isolates degraded only P(3HO) and copolymers of medium-chain-length (MCL) hydroxyalkanoic acids (HA) . Except for the gram-positive strain, which was able to hydrolyze P(3HO) and poly(3-hydroxybutyric acid) {P(3HB)}, no isolate was able to degrade polymers of short-chain-length HA, such as P(3HB) or poly(3-hydroxyvalerate) {P(3HV)} . All strains utilized a large variety of monomeric substrates for growth . All gram-negative strains, but not the gram-positive strain, accumulated poly(hydroxyalkanoic acids) (PHA), consisting of MCL HA, if they were cultivated under accumulation conditions . One strain, which was identified as Pseudomonas fluorescens GK13 (biovar V), was selected and the extracellular P(3HO) depolymerase of this strain was purified from the culture medium of P(3HO)-grown cells by chromatography with Octyl-Sepharose CL4B and by gel filtration with Superose 12 . The relative molecular weights of the native and sodium dodecyl sulfate-treated enzymes were 48,000 and 25,000, respectively . The purified enzyme hydrolyzed P(3HO), copolymers of MCL HA, and para-nitrophenyl esters of fatty acids . P(3HB), P(3HV), and characteristic substrates for lipases, such as Tween 80 or triolein, were not hydrolyzed . The P(3HO) depolymerase of P . fluorescens GK13 was insensitive to phenylmethylsulfonyl fluoride and dithioerythritol, unlike other PHA depolymerases . The dimeric ester of 3-hydroxyoctanoic acid was identified as the main product of enzymatic hydrolysis of P(3HO).(ABSTRACT TRUNCATED AT 250 WORDS)

Appl Environ Microbiol, 1993 Apr, 59(4), 1213 - 9
Detection of naturally occurring enteroviruses in waters by reverse transcription, polymerase chain reaction, and hybridization; Kopecka H et al.; Comparison in virus-seeded mineral water of three detection methods for enteroviruses, direct hybridization, cell culture, and reverse transcription into cDNA followed by polymerase chain reaction and hybridization, showed that the last procedure was 10 to 1,000 times more sensitive than detection by cell culture and 10(5) to 10(7) times more sensitive than direct hybridization . The presence of naturally occurring enteroviruses was also demonstrated in activated sludge and in concentrated and non-concentrated surface water samples by reverse transcription-polymerase chain reaction-hybridization . However, in activated sludge and in concentrated surface waters, enzymatic amplification was sometimes inhibited by contaminants.

Biol Chem Hoppe Seyler, 1993 Mar, 374(3), 175 - 81
Microbial metabolism of quinoline and related compounds . XVII . Degradation of 3-methylquinoline by Comamonas testosteroni 63; Schach S et al.; A bacterial strain which utilizes 3-methylquinoline as sole source of carbon, nitrogen and energy was isolated from activated sludge . On the basis of its morphological and physiological characteristics, this isolate was classified as Comamonas testosteroni . Four metabolites of 3-methylquinoline degradation were isolated from the culture supernatant and identified as 3-methyl-2-oxo-1,2-dihydroquinoline, 6-hydroxy-3-methyl-2-oxo-1,2-dihydroquinoline, 5,6-dihydroxy-3-methyl-2-oxo-1,2-dihydroquinoline and 2,5,6-trihydroxy-3-methylpyridine . Based on these results, a degradation pathway for 3-methylquinoline is proposed.

Folia Microbiol (Praha), 1993, 38(1), 43 - 8
Primary biodegradation of amine oxide and quaternary ammonium amphiphiles; Cupkova V et al.; Biodegradation of two amphiphilic "soft" antimicrobially active derivatives of lauric (dodecanoic) acid, a quaternary ammonium salt and an amine oxide bearing an amide or ester group, was followed using microorganisms from activated sludge . Primary biodegradation was determined by ion-selective electrodes, total biodegradation as the chemical oxygen demand . Though organic ammonium salts quickly undergo primary biodegradation, the rest of the molecule is difficult to destroy . In contrast, amine oxides are easily biodegradable.

Biosens Bioelectron, 1993, 8(1), 49 - 58
An activated sludge-based biosensor for rapid IC50 estimation and on-line toxicity monitoring; Kong Z et al.; The RODTOX (Rapid Oxygen Demand and TOXicity tester), an activated sludge-based respirographic biosensor, is a device for on-line monitoring of the short-term biochemical oxygen demand (stBOD) and potential toxicity of incoming wastewater on the basis of on-line interpretation of respirograms resulting from pulse additions of either calibration substrate or sample . The principle of toxicity detection is based on the comparison of calibration respirograms before and after receiving a potential toxicant . In this paper, the results of the RODTOX as an on-line toxicity monitor are presented . In addition, a simple and fast procedure to estimate the IC50 of a toxicant has been developed, and its validity and good repeatability demonstrated . The performance of this procedure is compared with that of the Microtox test.

Microbios, 1993, 73(295), 113 - 21
Copper accumulation by a strain of Pseudomonas putida; Wong PK et al.; A study on the copper accumulation by resting cells of copper-resistant bacteria, isolated from activated sludge and electroplating effluent, was conducted . The best selected strain, identified as Pseudomonas putida II-11, retained copper ions, Cu(II), as high as 6.5% of its dry weight . Bacterial cells grown in the sulphate-limiting medium had the highest copper removal capacity {RC, mg of Cu(II)/g of dry cells}, while the presence of glucose or sodium azide did not affect Cu(II) RC of the bacterial cells . A possible mechanism of Cu(II) accumulation by this bacterium is suggested.

Biodegradation, 1993, 4(1), 23 - 38
Effects of media composition on substrate removal by pure and mixed bacterial cultures; Grady CP Jr et al.; Continuous culture experiments with identical experimental designs were run with a mixed microbial community of activated sludge origin and an axenic bacterial culture derived from it . Each culture received 2-chlorophenol (2-CP) at a concentration of 160 mg/L as COD and L-lysine at a concentration of 65 mg/L as COD . A factorial experimental design was employed with dilution rate and media composition as the two controlled variables . Three dilution rates were studied: 0.015, 0.0325, and 0.05 h-1 . Media composition was changed by adding four biogenic compounds (butyric acid, thymine, glutamic acid and lactose) in equal COD proportions at total concentrations of 0, 34, 225, and 1462 mg/L as COD . The measured variables were the effluent concentrations of 2-CP as measured by the 4-aminoantipyrene test and lysine as measured by the o-diacetylbenzene procedure . The results suggest that community structure and substrate composition play important roles in the response of a microbial community to mixed substrates . The addition of more biogenic substrates to the axenic culture had a deleterious effect on the removal of both lysine and 2-CP, although the effect was much larger on lysine removal . In contrast, additional substrates had a positive effect on the removal of 2-CP by the mixed community and much less of a negative effect on the removal of lysine . The dilution rate at which the cultures were growing had relatively little impact on the responses to the additional substrates.

J Chem Technol Biotechnol, 1993, 56(1), 73 - 6
Biodegradation of phenol: a comparative study with and without applying magnetic fields; Jung J et al.; The objective of this work was to study the effect of magnetic fields on the rate of phenol biodegradation using immobilized activated sludge . A recirculation flow bioreactor employing immobilized bacterial beads was used with phenol as the substrate to study the biodegradation process . This study was conducted by applying separately the north pole and the south pole magnetic fields to the bioreactor . Rate of dissolved oxygen consumption, phenol concentration and extracellular protein concentration were the parameters monitored during the process . It was observed that by applying a magnetic south pole to the process, biodegradation in the form of biological oxidation was enhanced . A 30% increase in biodegradation rate was obtained by applying a magnetic south pole of strength of 0.45 Tesla to the bioreactor with immobilized microbial beads as compared to the control . Magnetic north pole irradiation inhibited this type of biooxidation . This process has potential for biological treatment of organic wastes.

Acta Microbiol Pol, 1993, 42(3-4), 303 - 13
Fungi in activated sludge biocenosis; Grabinska-Loniewska A et al.; It has been found that yeasts and yeast-like microorganisms are stable constituents of activated sludge biocenosis treating municipal wastewaters with a mixture of different industrial wastewaters at B upsilon values in the range of 1.3-1.7 kg COD m-3day-1 and B chi = 0.22-0.42 kg COD kg-1day-1 . The number of these microorganisms reached about 10(4) cells mg VSS-1 and as typical species Saccharomyces cerevisiae and Candida famata can be considered . Considerably less numerous (4-8 cells mg VSS-1) was the mycoflora of high loaded treatment systems of petrochemical wastewaters (B upsilon = 10.3-14.1 kg COD m-3day-1 and B chi = 1.06-1.92 kg COD kg-1day-1) and municipal wastewaters with a mixture of aromatic amines (B upsilon = 1200-2400 mg COD l-1 day-1 and B chi = 0.43-0.94 mg COD mg-1day-1) . Typical species for these sludges were Geotrichum candidum, G.klebahnii, G.sericeum, Trichosporon cutaneum and Sporobolomyces lactosus.

Appl Environ Microbiol, 1992 Nov, 58(11), 3514 - 6
Efficacy of activated sludge in removing Cryptosporidium parvum oocysts from sewage; Villacorta-Martinez de Maturana I et al.; Primary clarifier effluent (procedure B) and final effluent (procedure A) from a wastewater treatment plant were enriched with Cryptosporidium parvum oocysts obtained from the feces of naturally infected calves . Procedure B samples alone were subjected to a laboratory simulation of activated-sludge treatment . Coccidium-free neonatal CD-1 mice were then inoculated intragastrically with procedure A or procedure B samples . Seven days after inoculation, the intensity of oocyst infection in procedure B mice was 91% less than in procedure A mice (controls).

Appl Environ Microbiol, 1992 Oct, 58(10), 3380 - 6
Expression and transfer of engineered catabolic pathways harbored by Pseudomonas spp . introduced into activated sludge microcosms; Nusslein K et al.; Two genetically engineered microorganisms (GEMs), Pseudomonas sp . strain B13 FR1(pFRC20P) (FR120) and Pseudomonas putida KT2440(pWWO-EB62) (EB62), were introduced into activated sludge microcosms that had the level of aeration, nutrient makeup, and microbial community structure of activated sludge reactors . FR120 contains an experimentally assembled ortho cleavage route for simultaneous degradation of 3-chlorobenzoate (3CB) and 4-methyl benzoate (4MB); EB62 contains a derivative TOL plasmid-encoded degradative pathway for toluene experimentally evolved so that it additionally processes 4-ethyl benzoate (4EB) . Experiments assessed survival of the GEMs, their ability to degrade target substrates, and lateral transfer of plasmid-encoded recombinant DNA . GEMs added at initial densities of 10(6) to 10(7) bacteria per ml of activated sludge declined to stable population densities of 10(4) to 10(5) bacteria per ml . FR120 degraded combinations of 3CB and 4MB (1 mM each) following 3 days of adaptation in the microcosms . Indigenous microorganisms required an 8-day adaptation period before degradation of 4MB was observed; 3CB was degraded only after the concentration of 4MB was much reduced . The indigenous microbial community was killed when both compounds were present at concentrations of 4.0 mM . However, in parallel microcosms containing FR120, the microbial community maintained a normal density of viable cells . Indigenous microbes readily degraded 4EB (2 mM), and EB62 did not significantly increase the observed rate of degradation . In filter matings, transfer of pFRC20P, which specifies mobilization but not transfer functions, from FR120 to P . putida UWC1 was not detectable (< 10(-7) transconjugants per donor cell).(ABSTRACT TRUNCATED AT 250 WORDS)

Can J Microbiol, 1992 Sep, 38(9), 921 - 8
Glyphosate degradation by immobilized bacteria: laboratory studies showing feasibility for glyphosate removal from waste water; Heitkamp MA et al.; To evaluate immobilized bacteria technology for the removal of low levels of glyphosate (N-phosphonomethylglycine) from aqueous industrial effluents, microorganisms with glyphosate-degrading activity obtained from a fill and draw enrichment reactor inoculated with activated sludge were first exposed to glyphosate production wastes containing 500-2000 mg glyphosate/L . The microorganisms were then immobilized by adsorption onto a diatomaceous earth biocarrier contained in upflow Plexiglas columns . The columns were aerated, maintained at pH 7.0-8.0, incubated at 25 degrees C, supplemented with NH4NO3 (50 mg/L), and exposed to glyphosate process wastes pumped upflow through the biocarrier . Glyphosate degradation to aminomethylphosphonic acid was initially > 96% for 21 days of operation at flows yielding hydraulic residence times (HRTs) as short as 42 min . Higher flow rate studies showed > 98% removal of 50 mg glyphosate/L from the waste stream could be achieved at a HRT of 23 min . Glyphosate removal of > 99% at a 37-min HRT was achieved under similar conditions with a column inoculated with a pure culture of Pseudomonas sp . strain LBr, a bacterium known to have high glyphosate-degrading activity . After acid shocking (pH 2.8 for 18 h) of a column of immobilized bacteria, glyphosate-degrading activity was regained within 4 days without reinoculation . Although microbial growth and glyphosate degradation were not maintained under low organic nutrient conditions in the laboratory, the low levels of degradable carbon (45-94 mg/L) in the industrial effluent were sufficient to support prolonged glyphosate-degrading activity . The results demonstrated that immobilized bacteria technology is effective in removing low levels of glyphosate in high-volume liquid waste streams.

Appl Environ Microbiol, 1992 Sep, 58(9), 3083 - 7
Metabolism of hexadecyltrimethylammonium chloride in Pseudomonas strain B1; van Ginkel CG et al.; A bacterium (strain B1) utilizing hexadecyltrimethylammonium chloride as a carbon and energy source was isolated from activated sludge and tentatively identified as a Pseudomonas sp . This bacterium only grew on alkyltrimethylammonium salts (C12 to C22) and possible intermediates of hexadecyltrimethylammonium chloride breakdown such as hexadecanoate and acetate . Pseudomonas strain B1 did not grow on amines . Simultaneous adaptation studies suggested that the bacterium oxidized only the alkyl chain of hexadecyltrimethylammonium chloride . This was confirmed by the stoichiometric formation of trimethylamine from hexadecyltrimethylammonium chloride . The initial hexadecyltrimethylammonium chloride oxygenase activity, measured by its ability to form trimethylamine, was NAD(P)H and O2 dependent . Finally, assays of aldehyde dehydrogenase, hexadecanoyl-coenzyme A dehydrogenase, and isocitrate lyase in cell extracts revealed the potential of Pseudomonas strain B1 to metabolize the alkyl chain via beta-oxidation.

FEMS Microbiol Lett, 1992 Jul 1, 73(1-2), 171 - 3
Differentiation of polyphosphate and poly-beta-hydroxybutyrate granules in an Acinetobacter sp . isolated from activated sludge; Rees GN et al.; Cells containing polyphosphate 71 micrograms P (mg protein)-1 and no poly-beta-hydroxybutyrate showed metachromatic granules but no lipid granules; cells containing poly-beta-hydroxybutyrate (15% of dry weight) showed fluorescence lipid granules but no metachromatic granules; whereas cells containing both polyphosphate and poly-beta-hydroxybutyrate showed both types of granules . These observations, together with a critical review of the literature, show a clear distinction between metachromatic (or volutin) granules and lipid granules.

Mikrobiologiia, 1992 Jul-Aug, 61(4), 709 - 16
{Pathways of degradation of organic components of waste water of (meth)acrylate-producing factories to methane by communities of microorganisms of adapted and unadapted sludge}; Shtarkman NB et al.; Pathways of the degradation of the main compounds of (meth)acrylate-producing factories wastewater (methyl methacrylate, methyl and butyl acrylate, acrylate and methacrylate, acetone, isopropanol, butanol and methanol) by the anaerobic microbial consortium of mesophilic unadapted granulated sludge from the "UASB" reactor and of adapted activated sludge from the contact reactor were comparatively studied . It was shown that the degradation of fatty acids and alcohols took place in both types of sludge . Methacrylate, acrylate and acetone degradation occurred only in adapted sludge . Both types of sludge were characterized by the reversible conversion of acetone and isopropanol and by the presence of the isomeric transition of butyrate and isobutyrate too . The present results allow to suggest that the adaptation of activated sludge to substrate includes the accumulation of biomass of microorganisms capable of hydrolyze specific substrates into such general intermediates as low-molecular-weight fatty acid and alcohols further metabolized to methane and carbon dioxide.

Appl Environ Microbiol, 1992 Apr, 58(4), 1215 - 9
Glyphosate degradation by immobilized bacteria: field studies with industrial wastewater effluent; Hallas LE et al.; Immobilized bacteria have been shown in the laboratory to effectively remove glyphosate from wastewater effluent discharged from an activated sludge treatment system . Bacterial consortia in lab columns maintained a 99% glyphosate-degrading activity (GDA) at a hydraulic residence time of less than 20 min . In this study, a pilot plant (capacity, 45 liters/min) was used for a field demonstration . Initially, activated sludge was enriched for microbes with GDA during a 3-week biocarrier activation period . Wastewater effluent was then spiked with glyphosate and NH4Cl and recycled through the pilot plant column during start-up . Microbes with GDA were enhanced by maintaining the pH at less than 8 and adding yeast extract (less than 10 mg/liter) . Once the consortia were stabilized, the column capacity for glyphosate removal was determined in a 60-day continuous-flow study . Waste containing 50 mg of glyphosate per liter was pumped at increasing flow rates until a steady state was reached . A microbial GDA of greater than 90% was achieved at a 10-min hydraulic residence time (144 hydraulic turnovers per day) . Additional studies showed that microbes with GDA were recoverable within (i) 5 days of an acid shock and (ii) 3 days after a 21-day dormancy (low-flow, low-maintenance) mode . These results suggest that full-scale use of immobilized bacteria can be a cost-effective and dependable technique for the biotreatment of industrial wastewater.

Antonie Van Leeuwenhoek, 1992 Apr, 61(3), 245 - 8
Sporobolomyces lactosus, a new species of ballistosporous yeast equipped with ubiquinone-10; Slavikova E et al.; A new species of ballistospore-forming yeasts was recovered and its description given . Sporobolomyces lactosus, isolated from activated sludge treating petrochemical wastes, produces pinkish-coral to pink colored colonies, assimilates lactose and has Q-10 as the major ubiquinone.

Folia Microbiol (Praha), 1992, 37(4), 311 - 4
Enhanced biodegradation of a hard bis-quaternary ammonium salt; Cupkova V et al.; Bacterial strains with a high biodegradation potential were isolated from activated sludge . Their ability to decompose the hard bis-quaternary ammonium salt FB was determined by the method of chemical oxygen demand (COD) in a mineral medium, where the compound FB was the only source of carbon . The COD values were very low after 21 d and in the course of this period they reached zero level twice . The contribution of adsorption to decrease the COD value was small . The maximum COD decrease was accompanied by an increase of cell respiration . It is suggested that FB is effectively decomposed in spite of the fact that according to its structure it is a typical hard detergent.

Antibiot Khimioter, 1991 Dec, 36(12), 6 - 8
{Determining the level of total nitrogen in wastes from the microbiological industry}; Vlasenko IIu et al.; Optimization of the Kjeldahl method for determination of total nitrogen in the objects of microbial synthesis was performed in regard to biomass of the benzylpenicillin-producing culture, activated sludge and certain organic compounds . Mathematical processing of the data was carried out, which showed that the difference in the mean values for the five tested conditions of mineralization was insignificant . The method is useful in assaying the final and intermediate products as well as the waste in biotechnological production.

FEMS Microbiol Lett, 1991 Dec 1, 68(3), 267 - 72
Anaerobic degradation of 3-hydroxybenzoate by a newly isolated nitrate-reducing bacterium; Heising S et al.; A Gram-negative nitrate-reducing bacterium, strain Asl-3, was isolated from activated sludge with nitrate and 3-hydroxybenzoate as sole source of carbon and energy . The new isolate was facultatively anaerobic, catalase- and oxidase-positive and polarly monotrichously flagellated . In addition to nitrate, nitrite, N2O, and O2 served as electron acceptors . Growth with 3-hydroxybenzoate and nitrate was biphasic: nitrate was completely reduced to nitrite before nitrite reduction to N2 started . Benzoate, 3-hydroxybenzoate, 4-hydroxybenzoate, protocatechuate or phenyl-acetate served as electron and carbon source under aerobic and anaerobic conditions . During growth with excess carbon source, poly-beta-hydroxybutyrate was formed . These characteristics allow the affiliation of strain Asl-3 with the family Pseudomonadaceae . Analogous to the pathway of 4-hydroxybenzoate degradation in other bacteria, the initial step in anaerobic 3-hydroxybenzoate degradation by this organism was activation to 3-hydroxy-benzoyl-CoA in an ATP-consuming reaction . Cell extracts of 3-hydroxybenzoate-grown cells exhibited 3-hydroxybenzoyl-CoA synthetase activity of 190 nmol min-1 mg protein-1 as well as benzoyl-CoA synthetase activity of 86 nmol min-1 mg protein-1 . A reductive dehydroxylation of 3-hydroxybenzoyl-CoA could not be demonstrated due to rapid hydrolysis of chemically synthesized 3-hydroxybenzoyl-CoA by cell extracts.

J Appl Bacteriol, 1991 Oct, 71(4), 366 - 70
Enumeration of Aeromonas hydrophila from domestic wastewater treatment plants and surface waters; Poffe R et al.; Influents, effluents and sludges from sewage purification plants and surface water samples were examined quantitatively for Aeromonas hydrophila on the mA medium of Rippey and Cabelli . Between 10(4) and 10(6)/ml A . hydrophila were found in domestic wastewaters . On the average 99.975% were removed by activated sludge and 98.25% by trickling filters . Only 20.9% of A . hydrophila end up in the primary sludge, which contained up to 10(7)/g dry sludge . After 3 months, anaerobically (methane) fermented and partially dried sludge from trickling filters contained more than 10(6) A . hydrophila/g dry sludge . Surface water receiving raw sewage contained several hundreds of A . hydrophila/ml, comparable with the numbers found in effluent waters, while surface receiving no municipal wastewater and destined for the preparation of drinking water contained only small and negligible numbers . It was concluded that A . hydrophila was omnipresent in surface water.

J Dairy Sci, 1991 Jun, 74(6), 2015 - 9
Treatment of wastewater from a whey processing plant using activated sludge and anaerobic processes; Fang HH; Wastewater from a whey processing plant was treated in two on-site pilot plants, a three-stage activated sludge plant and an anaerobic reactor, each of which had the capacity of treating 230 L/h of wastewater . The activated sludge treatment was very effective . It reduced 99% of 5-d biochemical oxygen demand of the plant wastewater (from an average of 1062 to 9 mg/L) and 91% of total Kjeldahl nitrogen (from 109 to 10 mg/L) after a total retention time of 19.8 h . The intermediate 5-d biochemical oxygen demand reductions were 86% after 3.8 h in the first stage and 97% after another 8 h in the second stage . The completely mixed anaerobic reactor reduced only 87% of 5-d biochemical oxygen demand after 2 d of retention . However, with an additional 8 h of activated sludge treatment the total 5-d biochemical oxygen demand was reduced by 99% . Both pilot plants were operated smoothly in spite of the considerable fluctuations in pollutant levels of the plant wastewater.

Sci Total Environ, 1991 Mar, 100 Spec No, 177 - 205
Sewage sludge as a source of environmental selenium; Cappon CJ; Information is presented on the impact of land application of municipal sewage sludge on the selenium content and speciation in soil, groundwater and edible vegetation . Sources and typical concentrations of selenium in sludge are documented . A discussion of selenium uptake by agricultural crops from sludge-amended soil includes results from greenhouse and field studies . A comparison is made with crop selenium uptake from fly ash application . The effect of sludge treatment on animal and human dietary selenium intake is quantitatively evaluated and selenium guidelines for sludge application are summarized . The conclusion is made that future widespread use of sludge on agricultural land will result in increased selenium uptake by food crops and human dietary intake . While this may not present an increased human health risk, long-term risks are identified and recommendations are made to minimize them.

Appl Environ Microbiol, 1991 Feb, 57(2), 366 - 73
Survival and catabolic activity of natural and genetically engineered bacteria in a laboratory-scale activated-sludge unit; McClure NC et al.; The survival of selected naturally occurring and genetically engineered bacteria in a fully functional laboratory-scale activated-sludge unit (ASU) was investigated . The effect of the presence of 3-chlorobenzoate (3CB) on the survival of Pseudomonas putida UWC1, with or without a chimeric plasmid, pD10, which encodes 3CB catabolism, was determined . P . putida UWC1(pD10) did not enhance 3CB breakdown in the ASU, even following inoculation at a high concentration (3 x 10(8) CFU/ml) . The emergence of a natural, 3CB-degrading population appeared to have a detrimental effect on the survival of strain UWC1 in the ASU . The fate of two 3CB-utilizing bacteria, derived from activated-sludge microflora, was studied in experiments in which these strains were inoculated into the ASU . Both strains, AS2, an unmanipulated natural isolate which flocculated readily in liquid media, and P . putida ASR2.8, a transconjugant containing the recombinant plasmid pD10, survived for long periods in the ASU and enhanced 3CB breakdown at 15 degrees C . The results reported in this paper illustrate the importance of choosing strains which are well adapted to environmental conditions if the use of microbial inoculants for the breakdown of target pollutants is to be successful.

Appl Biochem Biotechnol, 1991 Spring, 28-29, 827 - 41
Novel biotreatment process for glycol waters; Raja LM et al.; Propylene oxide (PO), propylene glycol (PG), and polyols are produced from propylene via propylene chlorohydrin . Effluents from these plants contain biological oxygen demand/chemical oxygen demand (BOD/COD) loads besides high chloride concentrations . The high salinity poses severe problem to adopt conventional methods like activated sludge processes . Presently, a simple, economically viable and versatile microbiological process has been developed to get more than 90% biodegradation in terms of BOD/COD, utilizing specially developed Pseudomonas and Aerobacter . The process can tolerate high salinity up to 10 wt% NaCl or 5 wt% CaCl2 and can withstand wide variations in pH (5.5-11.0) and temperature (15-45 degrees C) . The biodegradation of glycols involves two steps . The enzymatic conversion of glycols to carboxylic and hydroxycarboxylic acids is aided by Pseudomonas . Further degradation to CO2 and H2O by carboxylic acid utilizing Aerobacter, and possible metabolic degradative pathway of glycols are discussed . Various process parameters obtained in the lab scale (50 L bioreactor) and pilot scale (20 m3 bioreactor), and unique features of our process are also discussed.

Microbios, 1991, 66(268-269), 133 - 42
Microbial lipids and stable foam formation in the activated sludge process; Goddard AJ et al.; The presence of fats and oils in sewage has been related to the formation of stable foams in activated sludge treatment systems . Foam forming microbes can utilise and, in some cases, store lipid substrates . Since surface lipids would confer the hydrophobicity necessary for flotation on the sludge biomass, the extractable lipids in foaming and non-foaming biomass samples were examined . Both pure mono-cultures and sludge samples were used . The results showed that, whilst there were some differences in the lipid profiles of the mono-cultures, the different sludge types did not show any significant pattern or variation which could be used as a lipid-based explanation for foam formation.

Acta Microbiol Pol, 1991, 40(3-4), 177 - 85
The effect of aromatic compounds on the work of activated sludge; Bieszkiewicz E et al.; The resistance of bacteria occurring in activated sludge purifying refining-petrochemical wastewaters to phenol, cresol and pirocatechin as well as the possibility of the purification of synthetic wastewaters carrying high concentrations of these compounds by sludge composed of resistant strains was studied . The most toxic of the studied compounds was phenol . Six out of 29 strains were resistant to high concentration of phenol (1000 mg/l) . Activated sludge synthesized from strains resistant to phenol, cresol and pyrocatechin was tolerant to high concentrations of these compounds . Worsening of the work of the sludge, expressed by decrease of GOD, was observed at the concentrations of phenol, cresol and pyrocatechin of 2000, 400 and 300 mg/l, respectively.

Appl Environ Microbiol, 1990 Oct, 56(10), 2967 - 73
Biodegradation of p-nitrophenol in an aqueous waste stream by immobilized bacteria; Heitkamp MA et al.; Microbiological analyses of activated sludge reactors after repeated exposure to 100 mg of p-nitrophenol (PNP) per liter resulted in the isolation of three Pseudomonas species able to utilize PNP as a sole source of carbon and energy . Cell suspensions of the three Pseudomonas sp., designated PNP1, PNP2, and PNP3, mineralized 70, 60, and 45% of a 70-mg/liter dose of PNP in 24, 48, and 96 h, respectively . Mass-balance analyses of PNP residues for all three cultures showed that undegraded PNP was less than 1% (less than 50 micrograms); volatile metabolites, less than 1%; cell residues, 8.4 to 14.9%; and water-soluble metabolites, 1.2 to 6.7% . A mixed culture of all three PNP-degrading Pseudomonas sp . was immobilized by adsorption onto diatomaceous earth biocarrier in a 1.75-liter Plexiglas column . The column was aerated and exposed to a synthetic waste stream containing 629 to 2,513 mg of PNP per liter at flow rates of 2 to 15 ml/min . Chemical loading studies showed that the threshold concentration for acute toxicity of PNP to the immobilized bacteria was 2,100 to 2,500 mg/liter . Further studies at PNP concentrations of 1,200 to 1,800 mg/liter showed that greater than 99 and 91 to 99% removal of PNP was achieved by immobilized bacteria at flow rates of 10 and 12 ml/min, respectively . These values represent hydraulic retention times of 48 to 58 min and PNP removal rates of 0.99 to 1.1 mg/h per g of biocarrier at 25 degrees C under optimal conditions . This study shows the successful use of immobilized bacteria technology to remove high concentrations of PNP from aqueous waste streams.

Int J Syst Bacteriol, 1990 Jul, 40(3), 292 - 6
Paracoccus kocurii sp . nov., a tetramethylammonium-assimilating bacterium; Ohara M et al.; A new species of tetramethylammonium-assimilating bacteria was isolated from an activated sludge which was used for the treatment of tetramethylammonium hydroxide contained in the wastewater from semiconductor manufacturing processes . Cells of the bacteria were gram-negative, nonmotile, short rods (0.5 to 0.8 micron by 0.7 to 1.1 microns) . The major respiratory quinone component of the bacteria was Q-10 . The G + C content was 71 mol% . Isolates are mesophilic and assimilate methylated amines such as tetramethylammonium, trimethylamine, dimethylamine, and methylamine under neutral conditions . The isolates resemble Paracoccus species with respect to morphology but were distinguishable from the known species of the genus . We propose Paracoccus kocurii sp . nov . The type strain is strain B (= JCM 7684).

Arch Tierernahr, 1990 Jul, 40(7), 569 - 82
{Determination of a prececal N-absorption from natural feed by 15N-labeled laboratory rats using the isotope dilution method}; Bergner H et al.; 60 Wistar rats (5 animals/group) received 12 different feedstuffs over a period of 7 days and were simultaneously labelled with 15N (orally by means of 15NH4Cl in the feed) . In the subsequent 5 days faeces were collected in order to determine the apparent and true digestibility of crude protein . On the 13th experimental day the animals were killed 3 hours after the intake of half the daily ration and the atom-% 15N excess (15N') was determined in the TCA-soluble and TCA-precipitable fractions of the blood plasma and the digesta of the 2nd and 3rd thirds of the small intestine . Precaecal N-absorption was calculated with the help of the quotient {formula: see text} the blood plasma and the digesta The following values (in %) were registered in comparison to true N-digestibility (in the following in brackets): casein = 95.8 (99.2), whole egg = 92.1 (97.5), fish meal = 85.8 (93.4), dried skimmed milk = 98.4 (96.1), soybean meal = 79.6 (90.6), assay protein = 94.2 (98.9), wheat = 92.9 (90.7), barley = 84.3 (84.8), yeast, grown on molasses = 85.6 (87.2), yeast, grown on whey = 86.1 (88.5), biomass of liquid manure = 43.6 (68.9), activated sludge = 54.4 (64.1) . One can conclude that the isotope dilution technique demonstrated here as an evaluation method is very well suited for the characterization of the N-digestibility of a feedstuff in the small intestine.

Int J Biol Macromol, 1990 Apr, 12(2), 106 - 11
Biosynthesis and characterization of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) in Alcaligenes eutrophus; Doi Y et al.; Copolyesters of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) were produced by Alcaligenes eutrophus at 30 degrees C in nitrogen-free culture solutions containing gamma-butyrolactone alone or with fructose or butyric acid as the carbon sources . When gamma-butyrolactone was used as the sole carbon source, the 4HB fraction in copolyester increased from 9 to 21 mol% as the concentration of gamma-butyrolactone in the culture solution increased from 10 to 25 g/l . The addition of fructose to the culture solution of gamma-butyrolactone resulted in a decrease in the 4HB fraction in copolyester . The copolyesters produced from gamma-butyrolactone and fructose by A . eutrophus were shown to have random sequence distribution of 3HB and 4HB units by analysis of the 125 MHz 13C n.m.r . spectra . In contrast, a mixture of random copolyesters with two different 4HB fractions was produced by A . eutrophus when gamma-butyrolactone and butyric acid were used as the carbon sources . These results are discussed on the basis of a proposed biosynthetic pathway of P(3HB-co-4HB) . The copolyester films became soft with an increase in the 4HB fraction, and the elongation to break at 23 degrees C increased from 5 to 444% as the 4HB fraction increased from 0 to 16 mol% . The P(3HB-co-10% 4HB) film was shown to be biodegradable in an activated sludge.

FEMS Microbiol Lett, 1990 Jan 15, 55(1-2), 85 - 8
Chromate-resistance in a chromate-reducing strain of Enterobacter cloacae; Ohtake H et al.; Resistance to toxic hexavalent chromium (chromate: CrO4(2)) in Enterobacter cloacae strain HO1, isolated from an activated sludge sample, was investigated under aerobic and anaerobic conditions . Decreased uptake of 51CrO4(2-) in E . cloacae strain HO1 was observed under aerobic conditions, when compared with a standard laboratory E . cloacae strain (IAM 1624) . Under anaerobic conditions E . cloacae strain HO1 was able to reduce hexavalent chromium to the less toxic trivalent form . When E . clocacae strain HO1 was grown with nitrate anaerobically, the cells were observed to lose simultaneously their chromate-reducing ability and chromate-resistance under anaerobic conditions.

Comput Biol Med, 1990, 20(3), 157 - 74
A numerical approach to activated sludge kinetics; Muslu Y; Mass balance equations for biomass and substrate are numerically solved to determine the effects of different variables on suspended growth systems . Dimensionless quantities and computer techniques are used to express the results generally . Monod kinetics and reactors-in-series principles are applied to explain variations in axial dispersion and waste-water quality experienced in real systems . An attempt has been made to determine the effluent concentrations as a function of two parameters, i.e . a dimensionless time and a dimensionless substrate concentration (of the incoming waste-water) . The computer results have been generalized in the form of design tables . An available approximate method for plug-flow reactors has been compared with the solution obtained in this way, and the resulting error has been demonstrated . In this study, results obtained from large numbers of reactors-in-series are reported to characterize plug-flow conditions . Performance of reactors subjected to varying degrees of axial dispersion will be stressed in a subsequent paper.

Microbios, 1990, 61(247), 99 - 120
Morphology, biometry and taxonomic position of two peritrich ciliate Protozoa found in activated sludge; Fernandez-Leborans G et al.; The morphology of two sessile peritrich species taken from a plant for the processing of activated sludge is described . One of these species, having a non-contractile, branched peduncle, belongs to the genus, Heteropolaria, and the other having a single, contractile stalk, is a member of the genus Vorticella . A statistical and biometric study is made of their morphological characteristics, and the taxonomic position of both ciliates is discussed.

Appl Environ Microbiol, 1989 Oct, 55(10), 2627 - 34
Survival of Pseudomonas putida UWC1 containing cloned catabolic genes in a model activated-sludge unit; McClure NC et al.; The possibility of the accidental or deliberate release of genetically engineered microorganisms into the environment has accentuated the need to study their survival in, and effect on, natural habitats . In this study, Pseudomonas putida UWC1 harboring a non-self-transmissible plasmid, pD10, encoding the breakdown of 3-chlorobenzoate was shown to survive in a fully functioning laboratory-scale activated-sludge unit (ASU) for more than 8 weeks . The ASU maintained a healthy, diverse protozoal population throughout the experiment, and the introduced strain did not adversely affect the functioning of the unit . Although plasmid pD10 was stably maintained in the host bacterium, the introduced strain did not enhance the degradation of 3-chlorobenzoate in the ASU . When reisolated from the ASU, derivatives of strain UWC1 (pD10) were identified which were able to transfer plasmid pD10 to a recipient strain, P . putida PaW340, indicating the in situ transfer of mobilizing plasmids from the indigenous population to the introduced strain . Results from plate filter matings showed that bacteria present in the activated-sludge population could act as recipients for plasmid pD10 and actively expressed genes carried on the plasmid . Some of these activated-sludge transconjugants gave higher rates of 3-chlorobenzoate breakdown than did strain UWC1(pD10) in batch culture.

Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi, 1989 Aug, 22(3), 217 - 25
The utilization of yeast in heavy wastewater treatment; Hu TL; Wastewater discharged from vermicelli factories has high concentration of COD and BOD, it is considered to be heavy wastewater . Strach degrading yeast was isolated and applied to treat the vermicelli wastewater . A semicontinuous yeast dominant activated sludge method and an immobilized yeast cells system were used in treating the clarified vermicelli wastewater . When the solid retention time and hydraulic retention time were kept at 7.14 days, using a semicontinuous culture, the solid loading was 0.48 g COD/g MLSS.day, volumetric loading was 1.03 kg COD/m3.day, and the COD removal was about 92% . When the yeast cells were immobilized with 1% Na-alginate solution, in the batch culture system, the COD removal of the immobilized cells was about 73% in 12 hours; with the air bubble system, the immobilized cells had the ability to remove COD of 90% . It indicated that the immobilized cells can treat heavy wastewater directly, and the hydraulic retention time could be reduced from 7.14 days to 24 hours.

Mikrobiol Zh, 1989 Jul-Aug, 51(4), 74 - 7
{Increased efficiency in the disinfection of sewage by lactic acid bacteria}; Bogdanova TF et al.; The antimicrobic properties have been studied in 30 strains of lactobacilli . As a result a strain, the strongest antagonist relative to choleric vibrios and other enteropathogenic microorganisms, is selected . Lactobacilli are found to retain their viability and biological activity in the activated sludge during the whole period of observation (6 months) . Biological disinfection of sewage is shown possible to be intensified using the activated sludge inoculated by the culture of the selected lactobacilli strain.

Zentralbl Hyg Umweltmed, 1989 May, 188(1-2), 66 - 83
{Electron microscopy of extracellular polymeric substances in activated sludge}; Bleich U et al.; Many problems arise with the TEM preparation of activated sludge flocs because the specimen material contains up to 98% of water . It is difficult to preserve the ultrastructure beyond dehydration and to make the polymers visible, which cannot be visualized with standard methods . The method presented here renders satisfying results . The important role of the exocellular polymers for the structure, size and density of flocs can be well illustrated . Furthermore many structure patterns could be found differing largely from each other but occurring regularly as structure elements.

Appl Environ Microbiol, 1989 Apr, 55(4), 897 - 901
Characterization of the bacterial population structure in an anaerobic-aerobic activated sludge system on the basis of respiratory quinone profiles; Hiraishi A et al.; Bacterial respiratory quinones were used as biomarkers for studying the bacterial population structure, especially the content of Acinetobacter species, in a laboratory-scale anaerobic-aerobic activated sludge system and in the standard aerobic system . All tested sludges contained both ubiquinone and menaquinone, with a molar ratio of about 1:0.5 . High-performance liquid chromatography showed that ubiquinone with eight isoprene units (Q-8) was present as the predominant ubiquinone, Q-10 was the second most common type, and Q-9 and other homologs were minor components in the anaerobic-aerobic sludge and the standard aerobic sludge . Bacteriological examination indicated that, in both sludge systems, Q-8-containing bacteria constituted a large proportion of the aerobic heterotrophic bacterial flora, but only a few strains with Q-9 were found . These findings demonstrate that the population of Acinetobacter species, which contain Q-9 as the major quinone, is negligible in those environments . The present results suggest that the introduction of anaerobic conditions into the aerobic batch process has little influence on the bacterial community structure.

Antibiot Khimioter, 1989 Feb, 34(2), 138 - 42
{Assessment of the degree of electrochemical treatment of sewage using biotesting}; Faingol'd ZL et al.; Studies were conducted on estimation of the toxicity levels in various oxygen-containing chlorine compounds formed during electrochemical treatment of sewage by using a culture isolated from activated sludge purifying antibiotic production waste . It was shown that the products formed during electrocatalytic treatment of solutions (concentration of NaCl 1.5-5 g/l, pH 2.0-12.0, volumetric current density up to 10 A/l) were not toxic and stimulated the growth of P . fluorescens.

Zentralbl Bakteriol Mikrobiol Hyg {B}, 1989 Feb, 187(3), 216 - 29
{Numerical identification of aquatic microorganisms using automated methods; for example, identification of bacteria from activated sludge}; Kampfer P et al.; A probability matrix for numerical identification of aquatic microorganisms was constructed using 90 miniaturized biochemical tests . More than 2000 reference strains originated from different culture collections and environmental strains identified by conventional methods were included in this matrix . All test result can be read visually and by photometer (automatically) . First applications of this system on aerobic and facultative anaerobic heterotrophic organisms from activated sludge revealed the advantage of this system compared to conventional methods and delivered further a detailed description of the activated sludge community.

Appl Environ Microbiol, 1989 Jan, 55(1), 219 - 23
Polyphosphate-degrading enzymes in Acinetobacter spp . and activated sludge; van Groenestijn JW et al.; Polyphosphate-degrading enzymes were studied in Acinetobacter spp . and activated sludge . Polyphosphate: AMP phosphotransferase activity in Acinetobacter strain 210A decreased with increasing growth rates . The activity of this enzyme in cell extracts of Acinetobacter strain 210A was maximal at a pH of 8.5 and a temperature of 40 degrees C and was stimulated by (NH4)2SO4 . The Km for AMP was 0.6 mM, and the Vmax was 60 nmol/min per mg of protein . Cell extracts of this strain also contained polyphosphatase, which was able to degrade native polyphosphate and synthetic magnesium polyphosphate and was strongly stimulated by 300 to 400 mM NH4Cl . A positive correlation was found between polyphosphate:AMP phosphotransferase activity, adenylate kinase activity, and phosphorus accumulation in six Acinetobacter strains . Significant activities of polyphosphate kinase were detected only in strain P, which contained no polyphosphate:AMP phosphotransferase . In samples of activated sludge from different plants, the activity of adenylate kinase correlated well with the ability of the sludge to remove phosphate biologically from wastewater.

Ann Ig, 1989 Jan-Apr, 1(1-2), 51 - 5
{Liquid hospital waste}; Fara GM et al.; Hospital sewage is distinct both from that of industrial origin and that from human housing, and is unique from the qualitative and quantitative standpoints . In fact the hospital is clearly different from a residential setting for the addition of technological activities, which are realised inside it, and it is not comparable to a traditional productive complex, because of the extreme variability--from one hospital to the other--of the presence of activities themselves, and this means important quali--quantitative differences of sewage produced from case to case . After all, the hospital cannot be compared to a centre of tertiary activities, which has, as regards sewage, the characteristics and the constancy of great inhabited places . Actually, its daily amount per patient is up to 1,000 L (3-5 times more than a standard citizen), because hospitals include, besides patients, physicians, nurses, technical and clerical staff and, for "teaching hospitals", also professors and students; in addition, the sewage from hospitals is composed of standard human sewage, plus: discharges from laboratories and technical equipments; drugs and their metabolites; disinfectants; and microorganisms, which are often characterized by the presence of antibiotic resistance of "infectious" nature (i.e . transmitted by resistance plasmids) . Such contaminants are not evenly generated, but focal points in the hospital and given hours during the day can help to identify where and when most of each contaminant is produced . A special problem arises from the interference of contaminants in hospital sewage on activated sludge plants; another is connected with the presence of toxic substances originated from biochemical laboratories, but the concentration of such substances appears to be lower than that tolerated according to the italian regulations.

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