Abstract: Several cultural conditions for high laccase production by Trametes versicolor, including initial medium pH value, metal ions Cu²⁺ and Mn²⁺ contents, types of inducers, as well as dosage and adding time of inducers were studied and optimized. The result showed that T. versicolor suited to grow and produce laccases at pH value 3.5-5.7, and unbuffered media were able to get good laccase productivity though buffered media could get higher laccase activity. Metal ions Cu²⁺ and Mn²⁺ in the culture could remarkably increase the activity of laccases. The optimal concentration of Cu²⁺ was 0.008-0.08mmol/L, and the optimal concentration of Mn²⁺ was about0.01mmol/L, when the culture contained0.1mmol/L2,5-dimethoxyaniline. Among five usual revulsants 2,5-dimethoxyaniline was the best one. Its optimal concentration was 0.4mmol/L and it should be added during the logarithmic growth phase. Under this condition, the suitable Cu²⁺ concentration was 0.4mmol/L. Enzymatic characterization indicated that residual activity was 95% and 80% of the origin after 6:h maintenance at 30 and 40℃, respectively. After 1:h maintenance at 60℃, the activity was left 14% of the origin. The optimal reaction temperature of laccase was 65℃ and the optimal reaction pH value was 2.4-3. Using the crude laccase, decolorization of 20 kinds of industrial dyes in common use were studied at pH value 5 and 40℃ and 13 kinds among them could be decolorized by the enzyme.

Key words: Trametes versicolor, laccase, enzyme character, dye decolorization