Heterologous production, characterization and dye decolorization ability of a novel thermostable laccase isoenzyme from Trametes trogii BAFC 463

Abstract

Laccases are multicopper polyphenol oxidases that are able to catalyze the oxidation of a wide range of phenolic compounds with the simultaneous reduction of O2 to H2O. Despite their promising industrial uses, feasible incorporation of laccases in harsh processes requires the bioprospecting and/or engineering of enzymes to be stable and active in acidic or alkaline pHs, high temperatures, oxidative conditions and tolerant to high salinity and/or organic solvents. Here we used a PCR-based screening to clone two novel laccase coding sequences from the white-rot basidiomycete Trametes trogii. Recombinant expression of lcc3 gene in Komagataella (=Pichia) pastoris showed that it encodes a thermo active and thermostable laccase with an optimum temperature of 50°C and with a half-life of 45 minutes at 70°C and a stability higher than 3 h at 60°C. Furthermore, recombinant LCC3 was capable of decolorizing between 50% and 100% of indigoid, triarylmethane, azoic and anthraquinonic synthetic dyes in the presence of the natural redox mediator acetosyringone within 2 h of incubation at pH 6 and 70°C.