[Characteristics of nitroreduction as the key stage in the microbial destruction of aromatic nitro compounds]

The reduction of nitrogroups of 2,4,6-trinitrotoluene (TNT) and other nitroaromatic compounds under the influence of Pseudomonas denitrificans and Escherichia coli enzymes was investigated. Quantitative measurements of the immediate stable products of TNT reduction showed that its reducing attack increased with bacterial age. However, preferential reduction of the nitrogroup in position 2 was typical of bacterial cells of any age, being maintained at pH 5.5 to 7.8. The bacterial reduction in vitro was NAD(P)H- (or NAD(P)H-generating systems) dependent. The nitroreduction was stimulated by only FAD and Mn2+ and Mg2+ out of flavins and metal ions tested. The lack of substrate specificity in the nitroreductases under study is indicated by the reducing capacity (in descending order) of nitroderivatives of benzene, toluene, benzoate, and phenol.