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...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.展开更多
从北京西郊森林土壤中分离到产生糖化生淀粉的葡糖化酶的特异腐质霉Humicola insolens HG‐618菌株。优化的产酶培养基如下:6%麦麸、2%玉米粉、0.7%磷酸氢二铵和1%玉米浆,p H 8.0,250m L三角瓶装40m L培养基,在40℃和280r/min培养90h。...从北京西郊森林土壤中分离到产生糖化生淀粉的葡糖化酶的特异腐质霉Humicola insolens HG‐618菌株。优化的产酶培养基如下:6%麦麸、2%玉米粉、0.7%磷酸氢二铵和1%玉米浆,p H 8.0,250m L三角瓶装40m L培养基,在40℃和280r/min培养90h。以生玉米淀粉为底物,发酵液中葡糖化酶活力为180U/m L。酶学性质试验表明,该酶的最适反应p H为6.0,最适反应温度为65℃;在p H 6.0–9.0范围酶活力稳定;酶热稳定性强,在60℃和p H 6.0保温8h,酶活力仍保留83%。一步糖化生玉米粉试验表明,在50m L 30%浓度生玉米粉浆和270U HG‐618葡糖化酶的反应体系中,采用自然p H 6.7,在55℃和100r/min条件下糖化40h。获得的糖化液还原糖浓度为17.1%(由酶产生的还原糖浓度为15.9%),生玉米粉中所含淀粉的糖化率为90%,且产生的糖全部为葡萄糖。因此,该葡糖化酶具有良好的一步糖化生玉米粉前景,它也可以用于生大米粉、生小麦粉和生马铃薯粉的直接糖化。展开更多
文摘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.
文摘从北京西郊森林土壤中分离到产生糖化生淀粉的葡糖化酶的特异腐质霉Humicola insolens HG‐618菌株。优化的产酶培养基如下:6%麦麸、2%玉米粉、0.7%磷酸氢二铵和1%玉米浆,p H 8.0,250m L三角瓶装40m L培养基,在40℃和280r/min培养90h。以生玉米淀粉为底物,发酵液中葡糖化酶活力为180U/m L。酶学性质试验表明,该酶的最适反应p H为6.0,最适反应温度为65℃;在p H 6.0–9.0范围酶活力稳定;酶热稳定性强,在60℃和p H 6.0保温8h,酶活力仍保留83%。一步糖化生玉米粉试验表明,在50m L 30%浓度生玉米粉浆和270U HG‐618葡糖化酶的反应体系中,采用自然p H 6.7,在55℃和100r/min条件下糖化40h。获得的糖化液还原糖浓度为17.1%(由酶产生的还原糖浓度为15.9%),生玉米粉中所含淀粉的糖化率为90%,且产生的糖全部为葡萄糖。因此,该葡糖化酶具有良好的一步糖化生玉米粉前景,它也可以用于生大米粉、生小麦粉和生马铃薯粉的直接糖化。
