A mutant strain T199 producing about 8 times as much β-glucanase as its parent strain trichoderma kningii T3 was obtained by treatment with ultraviolet light and N-methyl-N-nitro-N-nitrosoguanidine.Fermentation was conducted in 250mL flask,each containing 30mL of medium consisted of 5% corn cob powder,3% wheat bran and 1.4% nitrogen source No.10 ((NH 4) 2SO 4 10%,Peptone 20%,Yeast extract 15%).The optima culture conditions were as below:initial pH5.0,30℃,shaking speed 280r/min,and cultivation time 5d.Enzyme activity toward CMC-Na,lichenin,laminarin and barley β-glucan at pH 5.0 and 60℃ for 10min were 300,1100,12 and 1600 IU/mL,respectively.The optima pH and temperature for enzyme action toward barley β-glucan were pH 5.0 and 70℃,respectively.The enzyme was stable under below 50℃ and at pH 4.5～6.5.
