title: Successive transformation of benzo[a]pyrene by laccase of Trametes versicolor and pyrene-degrading Mycobacterium strains.
abstract: We previously hypothesized that polycyclic aromatic hydrocarbon (PAH)-degrading bacteria that produce laccase may enhance the degree of benzo[a]pyrene mineralization. However, whether the metabolites of benzo[a]pyrene oxidized by laccase can be further transformed by PAH degraders remains unknown. In this study, pyrene-degrading mycobacteria with diverse degradation properties were isolated and employed for investigating the subsequent transformation on the metabolites of benzo[a]pyrene oxidized by fungal laccase of Trametes versicolor. The results confirm the successive transformation of benzo[a]pyrene metabolites, 6-benzo[a]pyrenyl acetate, and quinones by Mycobacterium strains, and report the discovery of the involvement of a O-methylation mediated pathway in the process. In detail, the vast majority of metabolite 6-benzo[a]pyrenyl acetate was transformed into benzo[a]pyrene quinones or methoxybenzo[a]pyrene, via two distinct steps that were controlled by the catechol-O-methyltransferase mediated O-methylation, while quinones were reduced to dihydroxybenzo[a]pyrene and further transformed into dimethoxy derivatives.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Beijing East Road, 71, Nanjing, 210008, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zeng
authors.forename: Xiangui
authors.initials: X
authors.lastname: Lin
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhu
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Ming Hung
authors.initials: MH
authors.lastname: Wong
mesh_terms: D001564:Benzo(a)pyrene / Q000378:metabolism*; D001711:Biotransformation; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D042845:Laccase / Q000378:metabolism*; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000378:metabolism*; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D055454:Trametes / Q000201:enzymology*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D001564:Benzo(a)pyrene; D042845:Laccase