Abstract:

Laccase in Armillariella tabescens solid-state fermentation liquid was purified by ammonium sulfate salting-out and DEAE-cellulose column chromatography with an overall activity recovery of 42.3%. Electrophoretically pure laccase was obtained and its apparent molecular weight was approximately 55.6 kD, which was proved by SDS-PAGE analysis. The optimum reaction temperature and pH for this enzyme were 50 ℃ and 4.0, respectively, and the Km value was 0.018 mmol/L with 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) as a substrate. This enzyme maintained high and stable activity at pH 4.0－5.0. Various acid radical ions and metal ions had different effects on laccase activity, which was revealed an enhancement effect from SO42－ and Na+, and an inhibition effect from CO32－, Cu2+ and Mg2+.

Key words: Armillariella tabescens, laccase, purification, characteristics