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

The main contaminant at many military sites is 2,4,6-trinitrotoluene (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 extra cts of TNT-grown cells that were not present in the cell-free 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 [C-14]TNT was recovered as (CO2)-C-14. Analyses of culture supernatants detected some pathway intermediates in the productive removal of nitro groups from TNT, such as 2,4,6-trinitrobenzaldehyde, 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.