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Transformation of mono‐ and dichlorinated phenoxybenzoates by phenoxybenzoate‐dioxygenase in Pseudomonas pseudoalcaligenes POB310 and a modified diarylether‐metabolizing bacterium
Author(s) -
Halden Rolf U.,
Peters Eric G.,
Halden Barbara G.,
Dwyer Daryl F.
Publication year - 2000
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(20000705)69:1<107::aid-bit13>3.0.co;2-t
Subject(s) - dioxygenase , substrate (aquarium) , strain (injury) , chemistry , stereochemistry , yield (engineering) , bacteria , pseudomonas , biotransformation , enzyme , biochemistry , biology , materials science , ecology , genetics , anatomy , metallurgy
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 18 O 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 m M, μ max = 0.45 ± 0.03 h −1 , t d = 1.5 h, Y = 0.45 ± 0.03 g bio‐ mass · 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 m M, μ max = 0.31 ± 0.02 h −1 , t d = 2.2 h, Y = 0.39 ± 0.02 g biomass · g substrate −1 ). © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 69: 107–112, 2000.