Biotransformation of hydroxylaminobenzene and aminophenol by Pseudomonas putida 2NP8 cells grown in the presence of 3-nitrophenol

Biotransformation products of hydroxylaminobenzene and aminophenol produced by 3-nitrophenol-grown cells of Pseudomonas putida 2NP8, a strain grown on 2- and 3-nitrophenol, were characterized, Ammonia, 2-aminophenol, 4-aminop henol, 4-benzoquinone, N-acetyl-4-aminophenol, N-acetyl-2-aminophenal, 2-am inophenoxazine-3-one, 4-hydroquinone, and catechol were produced from hydro xylaminobenzene. Ammonia, N-acetyl-2-aminophenol, and 2-aminophenoxazine-3- one were produced from 2-aminophenol, All of these metabolites were also fo und in the nitrobenzene transformation medium, and this demonstrated that t hey were metabolites of nitrobenzene transformation via hydroxylaminobenzen e. Production of 2-aminophenoxazine-3-one indicated that oxidation of 2-ami nophenol via imine occurred. Rapid release of ammonia from a-aminophenol tr ansformation indicated that hydrolysis of the imine intermediate was the do minant reaction, The low level of 2-aminophenoxazine-3-one indicated that f ormation of this compound was probably due to a spontaneous reaction accomp anying oxidation of 2-aminophenol via imine, 4-Hydroquinone and catechol we re reduction products of 2- and 4-benzoquinones, Based on these transformat ion products, we propose a new ammonia release pathway via oxidation of ami nophenol to benzoquinone monoimine and subsequent hydrolysis for transforma tion of nitroaromatic compounds by 3-nitrophenol-grown cells of P, putida 2 NP8. We propose a parallel mechanism for 3-nitrophenol degradation in P, pu tida 2NP8, in which all of the possible intermediates are postulated.