Abstract: Strain Fomes fomentarius SO3 with high-yield laccase was screened from the Alter Mountains in Xinjiang.We optimized the fermentation technology and studied the partial enzymatic properties.The experimental result showed that the optimal carbon and nitrogen sources were wheat bran and yeast extract powder.Adding Mn²⁺,Ca2²⁺,Zn²⁺ and Mg²⁺ could promote the yield of laccase ,the effect of Cu²⁺ was adverse.Gallic acid and tannic acid made enzyme production peak two days ahead and ABTS may increase enzyme activity from 6 736 U/L to 8 470 U/L,orthogonal experiment L₉（3⁴） proved that optimum medium consists of 0.5% yeast extract powder,2.5 % wheat bran,0.5 % glucose and 0.5 %(NH₄)H₂PO₄,in this case,enzyme activity could reach to 10 863 U/L.The study of enzymatic properties showed optimal reaction temperature of laccase is 50 ℃ and there was still activity at 80 ℃,optimal reaction pH was 3.0 and enzyme activity was stable when pH was 4.0-5.0 and temperature was under 40 ℃.At the same time,Co²⁺,Cd²⁺,Cr²⁺nd Pb²⁺ could damage enzyme stability.Bidirectional electrophoresis was performed on the bacteria and fementation liquid in which isoelectric point of laccase was determined to be 4.1.A pure enzyme protein sequcence was obtained by mass spectrometry that showed the protein to be LaccaseE (Trames sp. 420).

Key words: Fomes fomentarius SO3, laccase, optimizing fermentation technology, enzymatic properties, mass spectrometry sequencing