Purification and partial characterization of laccase from Lachnocladium sp.

Laccase, a multicopper oxidase that catalyzes the oxidation of various aromatics, particularly phenolic substrates, e.g. hydroquinones guaiacol, 2,6-dimethoxyphenol or phenylene diamine, was purified and partially characterised from culture filtrates of a white rot fungus, Lachnocladium sp. This enzyme was purified by anion exchange and gel filtration chromatography. Laccase activity was determined using ABTS (2, 2’-azinobis-(3-ethylbenzthiazoline)-6-sulphonic acid) substrate. The culture filtrate had maximum laccase activity of 1.62 U/ml after 14 days of incubation. The purified laccase had an optimum temperature of 50oC and its optimum pH was 6 for ABTS. The activity of this enzyme was enhanced by Fe2+, Cu2+, Zn2+ and Ca2+, and was inhibited by EDTA and sodium iodide. Laccase from Lachnocladium sp. had a Km of 0.119 mM and a Vmax of 0.313 U.Keywords: Lachnocladium sp., anion exchange chromatography, gel filtration chromatography, ABTS, DM