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-aminophenol, 4-benzoquinone, N-acetyl-4-aminophenol, N-acetyl-2-aminophenol, 2-aminophenoxazine-3-one, 4-hydroquinone, and catechol were produced from hydroxylaminobenzene. Ammonia, N-acetyl-2-aminophenol, and 2-aminophenoxazine-3-one were produced from 2-aminophenol. All of these metabolites were also found in the nitrobenzene transformation medium, and this demonstrated that they were metabolites of nitrobenzene transformation via hydroxylaminobenzene. Production of 2-aminophenoxazine-3-one indicated that oxidation of 2-aminophenol via imine occurred. Rapid release of ammonia from 2-aminophenol transformation indicated that hydrolysis of the imine intermediate was the dominant reaction. The low level of 2-aminophenoxazine-3-one indicated that formation of this compound was probably due to a spontaneous reaction accompanying oxidation of 2-aminophenol via imine. 4-Hydroquinone and catechol were reduction products of 2- and 4-benzoquinones. Based on these transformation products, we propose a new ammonia release pathway via oxidation of aminophenol to benzoquinone monoimine and subsequent hydrolysis for transformation of nitroaromatic compounds by 3-nitrophenol-grown cells of P. putida 2NP8. We propose a parallel mechanism for 3-nitrophenol degradation in P. putida 2NP8, in which all of the possible intermediates are postulated.
Zhao
J S
JS
Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Singh
A
A
Huang
X D
XD
Ward
O P
OP
D000627:Aminophenols / Q000737:chemistry / Q000378:metabolism*; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D006898:Hydroxylamines / Q000737:chemistry / Q000378:metabolism*; D009596:Nitrophenols / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D016958:Pseudomonas putida / Q000254:growth & development / Q000378:metabolism*; D013997:Time Factors
D000627:Aminophenols; D003470:Culture Media; D006898:Hydroxylamines; D009596:Nitrophenols; C012484:phenylhydroxylamine; C049017:3-nitrophenol