Metabolism of 2,4,6-Trinitrotoluene by Pseudomonas sp. JLR11

The main contaminant at many military sites is 2,4,6trinitrotoluene (TNT). This explosive remains stable in the environment, and because it is toxic, there is an urgent need for remediation to clean up contaminated sites. Pseudomonas sp. JLR11 is a soil isolate able to use nitrate, TNT, or both as the N source under anaerobic conditions. At least two polypeptides were detected in cell-free extracts of TNT-grown cells that were not present in the cellfree extracts of nitrate-grown cells. Mass balances with unlabeled TNT revealed that about 85% of total N-TNT was incorporated as cell biomass, whereas only about 1% of [14C]TNT was recovered as CO2. Analyses of culture supernatants detected some pathway intermediates in the productive removal of nitro groups from TNT, such as 2,4,6trinitrobenzaldehyde, 2-nitro-4-hydroxybenzoic acid, 4-hydroxybenzaldehyde, and 4-hydroxybenzoic acid. This strain reduced a small fraction of the total TNT to monoaminodinitrotoluenes and diaminomononitrotoluenes, but these products accumulated with time and were not used by the strain as an N source. We discuss how the productive metabolism of TNT may occur.