Production and characterization of laccase from Pleurotus ferulae in submerged fermentation

Abstract

Pleurotus ferulae is a mushroom typically found in arid steppe that is distributed widely in the Junggar Basin of Xinjiang, China. In this work, laccase production by P. ferulae JM30X was optimized in terms of medium composition and culture conditions. After optimization, the highest laccase activity obtained was 6,832.86 U/L. A single isozyme with a molecular weight of 66 kDa was observed by SDS-PAGE and native-PAGE. Optimum pH and temperature were 3.0 and 50–70 °C, respectively. The best laccase substrate was ABTS, for which the Michaelis-Menten constant (K m) and catalytic efficiency (K cat/K m) value for P. ferulae laccase were 0.193 mM and 2.73 × 106 (mM s)−1, respectively. The activity of purified laccase was increased by more than four-fold by Cu2+, Mn2+ and Mg2+, while it was completely inhibited by Fe2+ and Fe3+. The production of laccase was influenced by the initial pH and K+ concentration, and the activity of purified laccase was enhanced by Cu2+, Mn2+ and Mg2+. This Pleurotus genus laccase from P. ferulae JM30X was analyzed by MS spectrum and the results are conducive to furthering our understanding of Pleurotus genus laccases.