乳酸克鲁维酵母超量表达葡萄糖氧化酶的研究

本研究应用具有超量分泌表达能力的乳酸克鲁维酵母(Kl SEL1基因突变型)、游离型载体p KDU7以及整合型表达载体p KLAC1,对具有5个氨基酸点突变的葡萄糖氧化酶(该突变酶的比活是野生型葡萄糖氧化酶的3.24倍)进行分泌表达。最终获得了一株可以超量分泌表达葡萄糖氧化酶的菌株,其最大产量为70±7 k U/L。这是现今已报道的分泌表达葡萄糖氧化酶能力最高的乳酸克鲁维重组菌株,为食品安全级的葡萄糖氧化酶的生产和应用提供了新途径。 

Over-expression of glucose oxidase gene in the Yeast Kluyveromyces lactis Kl SEL1 strain

In this study, the glucose oxidase gene with five amino acid sites-directed mutagenesis was synthesized.The activity of this mutant enzyme was 3.24 times than that of the wild type enzyme. The episomal vector p KDU7 and integrative vector p KLAC1 in which the glucose oxidas gene was recombined was constructed. Using these two vectors, the glucose oxidase gene was successfully recombined into K. lactis Kl SEL1 strain and a recombinant strain with efficient secretory over-expression of glucose oxidase was obtained.The result of flask-shaking fermentation showed that the production of glucose oxidase reached 70± 7 k U/L in the recombinant strain.This is the highest glucose oxidase-producing recombinant K.lactis strain reported so far.This technology will provide a promising approach for the production and application of glucose oxidase in food industry.