Abstract: [Objective] In order to enhance laccase activity of Lenzites gibbosa significantly,induction effects of different inducers and their optimal levels were studied.[Method] The effects of 12 kinds of inducers on laccase activity was determined under liquid culture through single factor tests. Several single factor screening tests consisting of optimal inducer's concentration, 2 inducers combination, Cu²⁺ concentration, inoculum volume, and static or shaking culture were conducted to gain further optimal conditions.[Result] The effects of biological inducer wheat bran and chemical inducer guaiacol on laccase production were better, and a high laccase activity was obtained when added 0.2 mmol·L^-1 Cu²⁺, the optimum levels of them were 1.5% and 1.00 mmol·L^-1, respectively; when one of them alone added, L. gibbosa laccase activity would reached 1 873.16 U·L^-1 and 1 975.72 U·L^-1, which were 13.0 and 13.7 times than the laccase activity of the initial medium, respectively. When 1.5% wheat bran and 1.00 mmol·L^-1 guaiacol were added simultaneously, the laccase activity was higher than that of each one of them alone added, and the peak value of laccase activity would reached 3 594.46 U·L^-1 on 11 day under 150 r·min^-1 shaking condition, which was 24.9 times than that of the initial medium.[Conclusion] Two inducers combination could enhance laccase activity substantially, the increase in laccase production induced by them was more obvious than that of culture condition optimization.

Key words: white-rot fungi, Lenzites gibbosa, inducer, laccase, enzyme activity