title: Biodegradation of dyes and polyaromatic hydrocarbons by two allelic forms of Lentinula edodes laccase expressed from Pichia pastoris.
abstract: Laccases from basidiomycetes are efficient enzymes in the degradation of xenobiotics. In this study we aimed to provide an industrially relevant expression system for Lentinula edodes laccases, to characterize their enzymatic properties, and to evaluate their potential in bioremediation. Two 1573-bp allelic laccase genes from L. edodes L54 were cloned based on gene models in the genome sequence. A novel upstream consensus (GCTCCGA/CCGGAG) was proposed as an alternative signature sequence for laccases. Both alleles were overexpressed in Pichia pastoris, purified, and verified by zymograms. Kinetic analyses suggested an order of catalytic efficiency of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)>2,6-dimethoxyphenol>guaiacol>l-3,4-dihydroxyphenylalanine>catechol, and a stable range of working temperature below 40 °C. With the appropriate mediators, 1-hydroxybenzotriazole and 2,2,6,6-tetramethylpiperidine-1-oxyl, the recombinant enzymes could catalyze a 70-100% decolorization of selected dyes and a complete degradation of anthracene. These results laid a solid foundation for the use of L. edodes laccases in bioremediations and for improvement with protein engineering.
authors: School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong. kinsingwong@cuhk.edu.hk
authors: Kin-Sing
authors: KS
authors: Wong
authors: Qianli
authors: Q
authors: Huang
authors: Chun-Hang
authors: CH
authors: Au
authors: Jun
authors: J
authors: Wang
authors: Hoi-Shan
authors: HS
authors: Kwan
mesh_terms: D000483:Alleles; D001673:Biodegradation, Environmental; D003001:Cloning, Molecular; D004396:Coloring Agents / Q000737:chemistry* / Q000302:isolation & purification; D004789:Enzyme Activation; D004795:Enzyme Stability; D024861:Genetic Enhancement / Q000379:methods*; D042845:Laccase / Q000235:genetics / Q000378:metabolism*; D010843:Pichia / Q000235:genetics / Q000378:metabolism*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry* / Q000302:isolation & purification; D020942:Shiitake Mushrooms / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D004396:Coloring Agents; D011084:Polycyclic Aromatic Hydrocarbons; D042845:Laccase