J. Navratilova, L. Kotouckova, J. Neca and E. Durnova,
Characterization of bacterial strain J7 and study of its degradation abilities, 11th Tomasek Days 2002 - Conference of Young Microbiologists, Brno, 5-7 June 2002; The conference was held by: Institute of Microbiology, Faculty of Medicine, Masaryk University in Brno, St. Anne’s Faculty Hospital in Brno, Czechoslovak Society for Microbiology, Society of Microbiology and Epidemiology of the Czech Medical Society of Jan Evangelista Purkyně

ABSTRACT

Nitroaromatic compounds are widely distributed in the environment because of their extensive use as drugs, herbicides, pesticides, explosives, dyes, and solvents. Nitroaromatics and products of their complete degradation have relatively high acute toxicity and some of them may be potential carcinogens. Many microorganisms are capable of degrading these compounds. The aim of this study was to isolate bacterial strains capable of degrading these nitroaromatics.

The bacterial strain J7 was isolated from soil by selective enrichment in mineral medium with 4-nitroguaiacol. The strain J7 was identified as Rhodococcus percolatus on the basis of morphology, physiology, biochemical characterization, whole cell fatty acid composition, and determination of partial sequence of genes for 16S rRNA. At this strain there was an extended ability to degrade nitroaromatic compounds. The strain J7 degrades e. g. 4-nitrocatechol, 4-nitrophenol, 4-nitroguaiacol, and others.

The degradation of nitroaromatics and the release of nitrites were measured spectrophotometrically on a Genesys spectrophotometer. The concentration of substrates was confirmed by HPLC analysis. The degradation of some nitroaromatics in concentration ranges of 0.025–0,1 mmol . l^-1 was studied on an automatic microbiological system Bioscreen C. The resting cell suspension was used for determination of the degradation of 4-nitroguaiacol.

Currently, studies of the enzymatic activity of the bacterial strain J7 are in the centre of scientists’ attention.