Abstract: Optimization of culture conditions for laccase production by xianggu mushroom (Lentinula edodes) was carried out and part characteristics of the crude laccase was investigated. Static cultivation was better than shaking cultivation for preparation of laccase from the edible mushroom. When culture pH value was ≥5.6, L. edodes was basically unable to grow. The best activity of laccase was found when pH value was around 3.5 and culture temperature was 25℃, though 20℃ was benefitial to the growth of mushroom. The concentration of Cu²⁺ from 0.2 to 1.0 mmol/L improved laccase production by L. edodes, while the optimal concentration of Cu²⁺ was 0.4 mmol/L. However, when concentration of Cu²⁺ exceeded 5 mmol/L, the growth of L. edodes was inhibited. Except 2,5-dimethoxyaniline, other four inducers, namely:ferulic acid, 2-methoxyphenol, gallic acid (3,4,5-trihydroxybenzoic acid) and veratryl alcohol (3,4-dimethoxybenzylalkohol) did not increase laccase activity significantly, but inhibited the mushroom's growth instead. Addition of Tween-80 affected the yield of laccase negatively. 2% of the activity of L.edodes laccase was retained after one hour incubation at 60℃. Using 2,2'-azino-di-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as substrate, optimal reaction temperature of the laccase was 65℃ and optimum pH value was 2.2.

Key words: Lentinula edodes, laccase