Jun Zeng Xiangui Lin Jing Zhang Hong Zhu Hong Chen Ming Hung Wong. Successive transformation of benzo[a]pyrene by laccase of Trametes versicolor and pyrene-degrading Mycobacterium strains. Appl Microbiol Biotechnol 2012 DOI 10.1007-s00253-012-4120-2.

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 Omethylation 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.