南极假丝酵母脂肪酶B的克隆、表达及发酵条件优化

Cloning, expression and optimization of fermentation conditions of Candida antarctica Lipase B

从原始菌株Candida antarctica ZJB09193出发,将南极假丝酵母脂肪酶B基因克隆至酵母表达载体pPICZαA,重组质粒线性化后导入表达宿主菌X-33,在甲醇诱导下,实现了CALB活性表达。从通气量、搅拌转速、初始pH、接种量和诱导剂量等方面对重组毕赤酵母的上罐发酵条件进行研究,最终确定通气量10 L/min,搅拌速度为800 r/min,初始pH 5.5,接种量10%,诱导剂量3500 mL可以达到较好的产酶量。确定DO为发酵控制的一个重要指标,在正确的溶氧校正下确保DO大于20%。

Candida antarctica Lipase B gene was cloned from strain C. antarctica ZJB09193, and the gene was subcloned into the vector pPICZα A. The recombinant plasmid was linearized and transformed into Pichia pastoris X-33. CALB was successfully expressed under the induction with methanol. Yeast fermentation conditions including ventilation volume, stirring speed, initial pH, inoculum size and dosage of inducer were studied. The optimal conditions of fermentation were as following： ventilation volume 10 L/min, stirring speed 800 r/min, initial pH 5.5, inoculum volume 10% and the dosage of inducer 3500 mL of methanol. DO was identified as an important factor and kept as 〉20% under the correct calibration.