β-葡萄糖苷酶的制备及在纤维素辅助水解上的应用研究

Study on Preparation of β-Glucosidase and Its Application in Enzymatic Hydrolysis of Cellulose

研究了固体发酵法制备β-葡萄糖苷酶及其在纤维素水解上的应用。黑曲霉NL02以玉米芯和麸皮为碳源固体发酵制备β-葡萄糖苷酶,培养5d,酶活力达到225.43IU/g(以干曲计)。粗β-葡萄糖苷酶酶液经硫酸铵沉淀、离子交换层析、凝胶过滤层析纯化,获得单一β-葡萄糖苷酶组分,酶活回收率和比活力分别为69.34%和133.88IU/mg。底物质量浓度为100g/L的稀硫酸预处理玉米秸秆,经酶用量为20FPIU/g(以纤维素计)的里氏木霉纤维素酶和4IU/g(以纤维素计)的β-葡萄糖苷酶水解48h,水解糖液中纤维二糖和葡萄糖质量浓度分别为1.12和42.68g/L,纤维素水解得率和可发酵性糖的比例分别为62.85%和97.44%。

Preparation of β-glucosidase by solid-state fermentation and its application in enzymatic hydrolysis of cellulose were investigated. The maximal β-glucosidase activity was 225.43 IU/g dry base （based on koji） when Aspergillus niger NL02 was employed using corn cob and wheat bran as carbon sources for 5 days cultivation. β-Glucosidase was purified to homogeneity by ammonium sulfate precipitation, anion-exchange chromatography and gel filtration chromatography. The recovery of enzyme activity and specific activity were 69.34 % and 133.88 IU/mg, respectively. Corn stalk pretreated by dilute sulfuric acid was hydrolyzed by the dosages of 20 FPIU/g （based on cellulose） Trichoderma reesei cellulase and 4 IU/g （based on cellulose）β-glucosidase at the substrate concentration of 100 g/L for 48 h, the concentration of cellobiose and glucose in hydrolysate were 1.12 and 42.68 g/L, respectively, the yield of enzymatic hydrolysis and the ratio of fermentable sugar were 62.85 % and 97.44 %, respectively.