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

Appl Environ Microbiol. 2000 Jun;66(6):2336-42. doi: 10.1128/AEM.66.6.2336-2342.2000.


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.

MeSH terms

  • Aminophenols / chemistry
  • Aminophenols / metabolism*
  • Biotransformation
  • Chromatography, High Pressure Liquid
  • Culture Media
  • Hydroxylamines / chemistry
  • Hydroxylamines / metabolism*
  • Nitrophenols / chemistry
  • Nitrophenols / metabolism*
  • Oxidation-Reduction
  • Pseudomonas putida / growth & development
  • Pseudomonas putida / metabolism*
  • Time Factors


  • Aminophenols
  • Culture Media
  • Hydroxylamines
  • Nitrophenols
  • phenylhydroxylamine
  • 3-nitrophenol