Bacterial strain XII, which belongs to the family Pseudomonad, utilizes 1-chloro-4-nitrobenzene as a sole source of carbon, nitrogen, and energy. Suspensions of 1-chloro-4-nitrobenzene -grown cells removed 1-chloro-4-nitrobenzene from culture fluids, and there was a concomitant release of ammonia and chloride. Under anaerobic conditions XII transformed 1-chloro-4-nitrobenzene into a product which was identified as 2-amino-5-chlorophenol by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. This transformation indicated that there was partial reduction of the nitro group to the hydroxylamino substituent, followed by Bamberger rearrangement. In the presence of oxygen but in the absence of NAD, fast transformation of 2-amino-5-chlorophenol into a transiently stable yellow product was observed with resting cells and cell extracts. This compound exhibited an absorption maximum at 395 nm and was further converted to a dead-end product with maxima at 226 and 272 nm. The compound formed was subsequently identified by 1H and 13C NMR spectroscopy and mass spectrometry as 5-chloropicolinic acid. In contrast, when NAD was added in the presence of oxygen, only minor amounts of 5-chloropicolinic acid were formed, and a new product, which exhibited an absorption maximum at 306 nm, accumulated.

Pseudomonas acidovorans, microbial degradation, NMR, 1-chloro-4-nitrobenzene