Identification of products resulting from the biological reduction of 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and 2,6-dinitrotoluene by Pseudomonas sp

Pseudomonas sp. clone A is able to use 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene, and 2,6-dinitrotoluene as an N-source after the enzymatic removal of nitro groups from the aromatic ring. We have identified in culture supernatants a hydride-TNT Meisenheimer complex, which is an intermediate in the removal of the first nitro group from the TNT aromatic ring. It has been shown in vitro that the hydride-TNT Meisenheimer complex is transformed to 2,4-dinitrotoluene and an unidentified compound, the molecular mass of which is 235. As side metabolites, reduced TNT derivatives-which cannot be used as an N-source by this bacterium-appeared in culture supernatants. 2-Hydroxylamino-4,6-dinitrotoluene, 4-hydroxylamino-2,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene, 2-amino-4,6-dinitrotoluene, and 2,4-diamino-6-nitrotoluene were found and chemically characterized. Spontaneous condensation of partially reduced TNT forms leads to the production of azoxytoluenes, and a possible condensation mechanism is discussed. For novel compounds, H-1 NMR, UV, and infrared data are provided. Therefore, Pseudomonas sp, clone A carries out two different initial reductive reactions in the meta holism of 2,4,6-trinitrotoluene; one process removes a nitro group from the aromatic ring and allows it to be used as an N-source, while the other gives rise to side products.