Transformation of mono- and dichlorinated phenoxybenzoates by phenoxybenzoate-dioxygenase in Pseudomonas pseudoalcaligenes POB310 and a modified diarylether-metabolizing bacterium

Rolf U. Halden, Eric G. Peters, Barbara G. Halden, Daryl F. Dwyer

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Pseudomonas pseudoalcaligenes POB310 contains genes that encode phenoxybenzoate dioxygenase. The enzyme transforms mono- and dichlorinated phenoxybenzoates to yield protocatechuate that is used as a growth substrate and chlorophenols that are nonmetabolizable. Mass spectral analysis of 18O metabolites obtained from the protocatechuate 3,4-dioxygenase-deficient mutant, POB310-B1, suggested that the reaction mechanism is a regioselective angular dioxygenation. A cloning vector containing reaction relevant genes (pD30.9) was transferred into Pseudomonas sp. strain B13 containing a modified ortho-cleavage pathway for aromatic compounds. The resultant Pseudomonas sp. strain B13-D5 (pD30.9) completely metabolized 3-(4- chlorophenoxy)benzoate. During growth on 3-phenoxybenzoate, strain B13-D5 (pD30.9) (K(s) = 0.70 ± 0.04 mM, μ(max) = 0.45 ± 0.03 h1, t(d) = 1.5 h, Y = 0.45 ± 0.03 g biomass · g substrate-1) was better adapted to low substrate concentrations, had a faster rate of growth, and a greater yield than POB310 (K(s) = 1.13 ± 0.06 mM, μ(max) = 0.31 ± 0.02 h-1, t(d) = 2.2 h, Y = 0.39 ± 0.02 g biomass · g substrate-1). (C) 2000 John Wiley and Sons, Inc.

Original languageEnglish (US)
Pages (from-to)107-112
Number of pages6
JournalBiotechnology and bioengineering
Volume69
Issue number1
DOIs
StatePublished - Jul 5 2000
Externally publishedYes

Keywords

  • Chlorinated diarylethers
  • POB-dioxygenase
  • Pseudomonas

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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