产β-环状糊精葡萄糖基转移酶高产菌株XW-6-66发酵条件和酶学性质的研究

Research on Enzymatic Properties and Fermentation Conditions of High-yield Strain XW-6-66 of Producing β-Cyclodextri Glucanotransferase

以一株β-环状糊精葡萄糖基转移酶高产菌株XW-6-66为研究对象,对其发酵条件及酶学特性进行了初步研究。该酶的最适反应温度为70℃,最适反应pH为9.0,酶学特性非常适合于环状糊精的工业化生产。对该菌发酵培养基的碳源、氮源及pH进行了单因子分析,采用3个因素正交实验确定该菌的最佳发酵培养基配方为:0.3%可溶性淀粉,1.0%牛肉浸膏,1%蛋白胨,0.2%Na2CO3,0.13%K2HPO4·3H2O,0.02%MgSO4·7H2O,pH为9.0。在该条件下,菌株XW-6-66产β-CGTase的酶活由优化前2173.33u/mL提高到3622.94u/mL。

A high-yield strain XW-6-66 of producing β-cyclodextri glucanotransferase was studied in this paper. Its fermentation conditions and its enzymatic properties were investigated. The best reaction temperature and reation pH value for such enzyme were 70 ℃ and 9.0 respectively. Its enzymatic properties were suitable for industralized production of cyclodextri glucanotransferase. In addition, one factor analysis of carbon source, nitrogen source and pH of the fermentation medium of such strain were carried out, and orthogonal experiments of three factors were done to determine the optimum fermentation medium as follows： 0.3 % soluble starch, 1.0 % beef extract, 1% tryptone, 0.2 % Na2CO3, 0.13 % K2HPO4· 3H2O,0.02 %MgSO4·7H2O, and pH=9.0. Under the above conditions, enzyme activity of β-CGTase increased from 2173.33 u/mL （before the optimization） to 3622.94 u/mL.