产β-葡聚糖酶基因工程菌发酵条件的优化

目的以1株酶产量高、耐热性好的重组大肠埃希菌BL21为材料发酵生产β-葡聚糖酶。方法选用麸皮、豆粕等农副产品配制复合碳源、氮源,优化半合成发酵培养基,并通过正常试验确定最佳培养条件。结果研究得到摇瓶水平产β-葡聚糖酶的最佳培养基（g/L）为：麸皮6.7,玉米粉1.7,豆粕13.8,豆粉13.8,酵母粉7.0,NH4Cl 7.0,Na2HPO4.12H2O3.0,MgSO4.7H2O0.75,CaCl20.5,吐温80 0.8%。通过正交试验确定了产酶最佳初始pH为6.2,装样量为35 mL/250 mL,接种量为1%。采用优化后的工艺,在37℃200 r/min培养过夜,经乳糖诱导6 h后,最高酶活可达到830.7 U/mL,是初始产酶条件的3.4倍。结论该半合成培养基在重组大肠埃希菌产β-葡聚糖酶方面具有很大优势。

Optimization of culture conditions of genetically engineered strain producing β-Glucanase

Objective To study the production of β-Glucanase using recombinant E.coli BL21,which was not only high yield but thermal stability.Method Agricultural by-products were used as the compound carbon and nitrogen sources to optimize the semi-synthetic medium,and confirm the best cultivation condition through an orthogonal test.Result The optimal composition of medium for the flask fermentation was as follows（g/L）： bran 6.7,corn flour 1.7,bean pulp 13.8,bean flour 13.8,yeast powder 7.0,NH4Cl 7.0,Na2HPO4·12H2O 3.0,MgSO4·7H2O 0.75,CaCl2 0.5,Tween-80 0.8%.The maximum β-Glucanase activity as high as 830.7 U/mL was obtained under 37 ℃,200 r/min with initial pH of 6.2,sample loading quantity of 35 mL/250 mL and inoculation volume o 1%,which was 3.4 times of that obtained under original conditions.Conclusion This semi-synthetic medium has great advantage in the production of β-Glucanase using recombinant E.coli BL21.