Purification and characterization of the extracellular laccase produced by Trametes polyzona WR710-1 under solid-state fermentation

Abstract

Laccase from Trametes polyzona WR710-1 was produced under solid-state fermentation using the peel from the Tangerine orange (Citrus reticulata Blanco) as substrate, and purified to homogeneity. This laccase was found to be a monomeric protein with a molecular mass of about 71kDa estimated by SDS-PAGE. The optimum pH was 2.0 for ABTS, 4.0 for L-DOPA, guaiacol, and catechol, and 5.0 for 2,6-DMP. The Km value of the enzyme for the substrate ABTS was 0.15mM, its corresponding Vmax value was 1.84mMmin-1, and the kcat/Km value was about 3960s-1mM-1. The enzyme activity was stable between pH 6.0 and 8.0, at temperatures of up to 40°C. The laccase was inhibited by more than 50% in the presence of 20mM NaCl, by 95% at 5mM of Fe2+, and it was completely inhibited by 0.1mM NaN3. The N-terminal amino acid sequence of this laccase is AVTPVADLQISNAGISPDTF, which is highly similar to those of laccases from other white-rot basidiomycetes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.