Metabolism of the herbicide bromoxynil by Klebsiella pneumoniae subsp. ozaenae

Appl Environ Microbiol. 1986 Aug;52(2):325-30. doi: 10.1128/aem.52.2.325-330.1986.


Enrichment of soil samples for organisms able to utilize the herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) as a nitrogen source yielded bacterial isolates capable of rapidly metabolizing this compound. One isolate, identified as Klebsiella pneumoniae subsp. ozaenae, could completely convert 0.05% bromoxynil to 3,5-dibromo-4-hydroxybenzoic acid and use the liberated ammonia as a sole nitrogen source. Assays of cell extracts of this organism for the ability to produce ammonia from bromoxynil revealed the presence of a nitrilase (EC 3.5.51) activity. The enzyme could not utilize 3,5-dibromo-4-hydroxybenzamide as a substrate, and no 3,5-dibromo-4-hydroxybenzamide could be detected as a product of bromoxynil transformation. Comparison of related aromatic nitriles as substrates demonstrated that the Klebsiella enzyme is highly specific for bromoxynil.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminohydrolases / metabolism
  • Kinetics
  • Klebsiella pneumoniae / growth & development
  • Klebsiella pneumoniae / isolation & purification
  • Klebsiella pneumoniae / metabolism*
  • Nitriles / metabolism*
  • Soil Microbiology
  • Substrate Specificity


  • Nitriles
  • Aminohydrolases
  • bromoxynil nitrilase
  • bromoxynil