Isolation, Purification and Characterization of Laccase from the White-rot Fungus Trametes Versicolor

Laccase (benzendiol:oxygen oxidoreductase; E.C.1.10.3.2) is a copper – containing enzyme, part of the group of so-called blue oxidases. The enzyme catalyzes the oxidation of many phenolic compounds and aromatic amines using molecular oxygen as a terminal electron acceptor. Laccases are widely distributed in higher plants, bacteria and fungi. Trametes versicolor is a white-rot fungus that produces laccase as extracellular enzyme. In this study different methods for purification of laccase from new isolate of Trametes versicolor were tested. Optimal results were achieved when the enzyme was precipitated with 60% acetone followed by size-exclusion chromatography (SEC). The partially purified enzyme showed pH optimum at 5.0 and temperature optimum at 42.5 ˚C. The kinetic constants Km and Vmax for syringaldazine were also determined - 0.5 mM and 5000 μM/min respectively. The laccase was stable in broad pH and temperature ranges. Moreover the enzyme remained fully active in 25 % acetone and ethanol for 48 hours. Cd2+ inhibited 60 % of enzyme activity.