Cometabolic biotransformation of nitrobenzene by 3-nitrophenol degrading Pseudomonas putida 2NP8

A strain of Pseudomonas putida (2NP8) capable of growing on both 2-nitrophenol and 3-nitrophenol, but not on nitrobenzene (NB), was isolated from municipal activated sludge. 2-Nitrophenol was degraded by this strain with production of nitrite. Degradation of 3-nitrophenol resulted in the formation of ammonia. Cells grown on 2-nitrophenol did not degrade nitrobenzene. A specific nitrobenzene degradation activity was induced by 3-nitrophenol. Ammonia, nitrosobenzene, and hydroxylaminobenzene have been detected as metabolites of nitrobenzene degradation by cells grown in the presence of 3-nitrophenol. These results indicated a NB cometabolism mediated by 3-nitrophenol nitroreductase.