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Amplification of toluene dioxygenase genes in a hybrid Pseudomonas strain to enhance the biodegradation of benzene, toluene, and p ‐xylene mixture
Author(s) -
Lee JangYoung,
Jung KwanHye,
Kim HakSung
Publication year - 1995
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/bit.260450605
Subject(s) - pseudomonas putida , toluene , benzene , biodegradation , xylene , chemistry , strain (injury) , pseudomonadales , pseudomonadaceae , pseudomonas , biochemistry , organic chemistry , bacteria , gene , biology , genetics , anatomy
A hybrid metabolic pathway through which benzene, toluene, and p ‐xylene (BTX) mixture could be simultaneously mineralized was previously constructed in Pseudomonas putida TB101 (Lee, Roh, Kim, Biotechnol. Bioeng 43: 1146–1152, 1994). In this work, we improved the performance of the hybrid pathway by cloning the todC1C2BA genes in the broad‐host‐range multicopy vector RSF1010 and by introducing the resulting plasmid pTOL037 into P. putida mt‐2 which harbors the archetypal TOL plasmid. As a result, a new hybrid strain, P. putida TB103, possessing the enhanced activity of toluene dioxygenase in the hybrid pathway was constructed. The degradation rates of benzene, toluene, and p ‐xylene by P. putida TB103 were increased by about 9.3‐, 3.7‐, and 1.4‐fold, respectively, compared with those by previously constructed P . putida TB101. Apparently, this improved capability of P. putida TB103 for the degradation of BTX mixture resulted from the amplification of the todC1C2BA genes. Furthermore, a relatively long lag period for benzene degradation observed when P. putida TB101 was used for the degradation of BTX mixture at low dissolved oxygen (DO) tension disappeared when P. putida TB103 was employed. © 1995 John Wiley & Sons, Inc.