Biochemical and genetic bases of microbial degradation of polychlorinated biphenyls (PCBs)

The Journal of General and Applied Microbiology

Kensuke Furukawa¹ 

[1] Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University

关键词: biphenyl;    biphenyl dioxygenase;    bph genes;    microbial degradation;    molecular breeding;    PCB;    polychlorinated biphenyls;   

DOI  :  10.2323/jgam.46.283

学科分类：微生物学和免疫学

来源: Applied Microbiology, Molecular and Cellulrar Biosciences Research Foundation

【 摘 要 】

The microbial degradation of polychlorinated biphenyls (PCBs) has been extensively conducted by many workers, and the following general results have been obtained. (1) PCBs are degraded oxidatively by aerobic bacteria and other microorganisms such as white rot fungi. PCBs are also reductively dehalogenated by anaerobic microbial consortia. (2) The biodegradability of PCBs is highly dependent on chlorine substitution, i.e., number and position of chlorine. The degradation and dehalogenation capabilities are also highly strain dependent. (3) Biphenyl-utilizing bacteria can cometabolize many PCB congeners to chlorobenzoates by biphenl-catabolic enzymes. (4) Enzymes involved in the PCB degradation were purified and characterized. Biphenyl dioxygenase, ring-cleavage dioxygenase, and hydrolase are crystallized, and two ring-cleavage dioxygenases are being solved by x-ray crystallography. (5) The bph gene clusters responsible for PCB degradation are cloned from a variety of bacterial strains. The structure and function are analyzed with respect to the evolutionary relationship. (6) The molecular engineering of biphenyl dioxygenases is successfully performed by DNA shuffling, domain exchange, and subunit exchange. The evolved enzymes exhibit wide and enhanced degradation capacities for PCBs and other aromatic compounds.

【 授权许可】

Unknown