A double mutant of Pseudomonas putida JLR11 deficient in the synthesis of the nitroreductase PnrA and assimilatory nitrite reductase NasB is impaired for growth on 2,4,6‐trinitrotoluene (TNT)

Abstract

Pseudomonas putida JLR11 can grow on 2,4,6-trinitrotoluene (TNT) as the sole nitrogen source. We created nasB (nitrite reductase), pnrA (nitroaromatic reductase) and pnrA nasB mutants and tested their growth with TNT as the sole N source. The nasB and pnrA mutants grew at a reduced rate on TNT, whereas the double nasB pnrA mutant did not. This suggests that P. putida JLR11 carries out multiple enzymatic attacks on TNT-releasing nitrite and/or ammonium. The PnrA nitroreductase plays a key role in the reduction of TNT to 2,6-dinitro-4-hydroxylaminotoluene and the subsequent release of ammonium for growth.