Production of a recombinant laccase from Pichia pastoris and biodegradation of chlorpyrifos in a laccase/vanillin system.

TitleProduction of a recombinant laccase from Pichia pastoris and biodegradation of chlorpyrifos in a laccase/vanillin system.
Publication TypeJournal Article
Year of Publication2013
AuthorsXie H, Li Q, Wang M, Zhao L
JournalJournal of microbiology and biotechnology
Volume23
Issue6
Pagination864-71
Date Published2013 Jun 28
Abstract

The recombinant strain P. pastoris GS115-lccC was used to produce laccase with high activity. Factors influencing laccase expression, such as pH, methanol concentration, copper concentration, peptone concentration, shaker rotate speed, and medium volume were investigated. Under the optimal conditions, laccase activity reached 12,344 U/L on day 15. The recombinant enzyme was purified by precipitating and dialyzing to electrophoretic homogeneity, and was estimated to have a molecular mass of about 58 kDa. When guaiacol was the substrate, the laccase showed the highest activity at pH 5.0 and was stable when the pH was 4.5~6.0. The optimal temperature for the laccase to oxidize guaiacol was 60°C, but it was not stable at high temperature. The enzyme could remain stable at 30°C for 5 days. The recombinant laccase was used to degrade chlorpyrifos in several laccase/mediator systems. Among three synthetic mediators (ABTS, HBT, VA) and three natural mediators (vanillin, 2,6-DMP, and guaiacol), vanillin showed the most enhancement on degradation of chlorpyrifos. Both laccase and vanillin were responsible for the degradation of chlorpyrifos. A higher dosage of vanillin may promote a higher level of degradation of chlorpyrifos, and the 2-step addition of vanillin led to 98% chlorpyrifos degradation. The degradation of chlorpyrifos was faster in the L/V system (kobs = 0.151) than that in the buffer solution (kobs = 0.028).

DOI10.5603/CJ.a2013.0057
Alternate JournalJ. Microbiol. Biotechnol.