Title Improvement of 4-chlorobiphenyl degradation bya recombinant strain, pseudomonas sp. DJ12-C
Author Kim, Ji Young · Kim, Young Chang · Lim, Jai Yun · Lee, Ki Sung¹ · Ka, Jong Ok² · Min, Kyung Hee² · Kim, Chi Kyung *
Address Department of Microbiology, Chungbuk National University; ¹Department of Biology, Pai-Chai University; ²Research Center for Molecular Microbiology, Seoul National University
Bibliography Journal of Microbiology, 35(1),53-60, 1997,
Key Words 4-chlorobiphenyl, degradation, cloning of pcbC, intragenic recombination, Pseudomonas sp. DJ12-E
Abstract Pseudomonas sp. P20 and Pseudomonas sp. DJ-12 isolated from the polluted environment are capable of degrading biphenyl and 4-chlorobiphenyl (4CB) to produce benzoic acid and 4-chlorobenzoic acid (4CBA) respectively, by pcbABCD-encoded enzymes. 4CBA can be further degraded by Pseudomonas sp. DJ-12, but not by Pseudomonas sp P20. However, the meta-cleavage activities of 2,3-dihydroxybiphenyl (2, 3-DHBP) and 4-chloro-2,3-DHBP dioxygenases (2, 3-DHBD) encoded by pcbC in Pseudomonas sp. P20 were stronger than Pseudomonas sp. DJ-12. In this study, the pcbC gene encoding 2, 3-DHBD was cloned from the genomic DNA of Pseudomonas sp. P20 by using pKT230. A hybrid plasmid pKK1 was constructed and E. coli KK1 transformant was selected by transforming the pKK1 hybrid plasmid carrying pcbC into E. coli XL1-Blue. By transferring the pKK1 plasmide of E. coli KK1 into Pseudomonas sp. DJ-12 by conjugation, a recombinant strain Pseudomonas sp. P20, Pseudomonas sp. DJ-12, and the recombinant cell assay methods. Pseudomonas sp. DJ12-C readily degraded 4CB and 2, 3-DHBP to produce 2-hydroxy-6-oxo-6-phenylhexa-2, 4-dienoic acid (HOPDA), and the resulting 4CBA and benzoic acid were continuously catabolized. Pseudomonas sp. DJ12-C degraded 1 mM 4CB completely after incubation for 20 h, but Pseudomonas sp. P20 and Pseudomonas sp. DJ-12 showed only 90% and Pseudomonas sp. DJ-12 had, but its degradation activity to 2, 3-DHBP, 3-methylcatechol, and catechol was improved.
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