Identification of the biochemical degradation pathway of triazophos and its intermediate in Diaphorobacter sp. TPD-1

Curr Microbiol. 2011 Apr;62(4):1294-301. doi: 10.1007/s00284-010-9859-z. Epub 2011 Jan 7.

Abstract

Triazophos is one of the most widely used organophosphorus insecticides usually detectable in the environment. A bacterial strain, Diaphorobacter sp. TPD-1, capable of using triazophos and its intermediate, 1-phenyl-3-hydroxy-1,2,4-triazole (PHT), as its sole carbon sources for growth was isolated from a triazophos-contaminated soil in China. This strain could completely degrade 50 mg l(-1) triazophos and PHT to non-detectable level in 24 and 56 h, respectively. During PHT degradation, three metabolites were detected and identified based on tandem mass spectrometry (MS/MS) analysis. Using this information, a biochemical degradation pathway of triazophos by Diaphorobacter sp. TPD-1 was proposed. The first step involved in the degradation of triazophos is the hydrolysis of the P-O ester bond of triazophos to form PHT and o,o-diethyl phosphorothioic acid, then the triazol ring of PHT is subsequently cleaved to form (E)-1-formyl-2-phenyldiazene. Subsequently, (E)-1-formyl-2-phenyldiazene is transformed to 2-phenylhydrazinecarboxylic acid by adding one molecular of H(2)O. Finally, the carboxyl group of 2-phenylhydrazinecarboxylic acid is decarboxylated to form phenylhydrazine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biodegradation, Environmental
  • China
  • Comamonadaceae / chemistry
  • Comamonadaceae / isolation & purification
  • Comamonadaceae / metabolism*
  • Hydrolysis
  • Insecticides / chemistry
  • Insecticides / metabolism*
  • Molecular Structure
  • Organothiophosphates / chemistry
  • Organothiophosphates / metabolism*
  • Soil Microbiology
  • Triazoles / chemistry
  • Triazoles / metabolism*

Substances

  • Insecticides
  • Organothiophosphates
  • Triazoles
  • triazophos