Zeng J Lin XG Zhang J et al.. Oxidation of polycyclic aromatic hydrocarbons by the bacterial laccase CueO from E. coli. Applied Microbiology And Biotechnology 2011 89(6): 1841-1849. (IF 3.280 工程技术，二区）
Abstract
Laccases produced by white rot fungi are capable of rapidly oxidizing benzo[a]pyrene. We hypothesize that the polycyclic aromatic hydrocarbon (PAH)-degrading bacteria producing laccase can enhance the degree of benzo[a]pyrene mineralization. However fungal laccases are glycoproteins which cannot be glycosylated in bacteria and there is no evidence to show that bacterial laccases can oxidize benzo[a]pyrene. In this study the in vitro oxidation of PAHs by crude preparations of the bacterial laccase CueO from Escherichia coli was investigated. The results revealed that the crude CueO catalyzed the oxidation of anthracene and benzo[a]pyrene in the same way as the fungal laccase from Trametes versicolor but showed specific characteristics such as thermostability and copper dependence. In the presence of 22′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) high amounts of anthracene and benzo[a]pyrene 80% and 97% respectively were transformed under optimal conditions of 60°C pH 5 and 5 mmol l−1 CuCl2 after a 24-h incubation period. Other PAHs including fluorene acenaphthylene phenanthrene and benzo[a]anthracene were also oxidized by the crude CueO. These findings indicated the potential application of prokaryotic laccases in enhancing the mineralization of benzo[a]pyrene by PAH-degrading bacteria.
