[Transformation of 2,4,6-trinitrotoluene during oxygen and nitrate respiration in Pseudomonas fluorescens]. / Prevrashchenie 2,4,6-trinitrotoluola v usloviiakh kislorodnogo i nitratnogo dykhaniia Pseudomonas fluorescens.

A study of the metabolic pathway and the rate of 2,4,6-trinitrotoluene (TNT) transformation depending on the nature of the electron acceptor in the electron transport chain of Pseudomonas fluorescens B-3468 revealed that the first reaction of nitroreduction of TNT resulting in formation of 2-amino-4,6-dinitrotoluene (2A) and 4-amino-2,6-dinitrotoluene (4A) became more active in case of nitrate respiration as compared to oxygen respiration; a TNT decrease was 100 and 66%, respectively. The same tendency but much more pronounced was observed at the next stage of nitroreduction that lead to 2,4-diamino-6-nitrotoluene (2,4DA). On the contrary, aerobic conditions are more preferable for the subsequent destruction of 2,4DA. Thus monoamino derivatives, 2A and 4A, predominated under anaerobic conditions, whereas 2,4DA under anaerobic ones (85 and 69% of the total nitrogen-containing metabolites), respectively. Phloroglucinol and pyrogallol accumulated in the culture liquid when the bacteria were grown on a medium containing 2,4DA as a sole source of nitrogen. Their role as intermediates was proved by the results obtained by studying oxidative activity of the cells grown in the presence of 2,4DA and phloroglucinol.

[Possibilities for the deep bacterial destruction of 2,4,6-trinitrotoluene]. / Izuchenie vozmozhnosti glubokoi bakterial'noi destruktsii 2,4,6-trinitrotoluola.

The possibility of 2,4,6-trinitrotoluene (TNT) deep destruction (the aromatic cycle fission inclusive) by Pseudomonas fluorescens B-3468 is reported for the first time. The formation of nitrogen-free metabolites, viz. phloroglucinol and pyrogallol, is preceded by the NAD(P)H-dependent deamination of 2,4-diamino-6-nitrotoluene (2,4-DA), a TNT intermediate. 30% of 2,4-DA nitrogen in released as ammonium under the action of an induced cell-free extract in the presence of the preferential co-factor NADH (together with FAD). The elevated pyrogallol-decomposing activity in cells grown on 2,4-DA, phloroglucinol and pyrogallol as well as the induction of the pyrocatechase activity in cells grown on the above substrates, together with the earlier reported accumulation of phloroglucinol and pyrogallol upon 2,4-DA utilization, indicated that the enzyme might be involved in the TNT cycle cleavage. The participation of NADH-dependent glutamate dehydrogenase in 2,4-DA nitrogen utilization is supported by experimental evidence.