产α-葡萄糖苷酶抑制剂酵母菌的筛选、发酵条件优化及酶动力学研究

Screening,Fermentation Conditions Optimization and Enzymatic Kinetics ofα-Glucosidase Inhibitor-Producing Yeasts

目的:筛选产α-葡萄糖苷酶抑制剂酵母菌,以丰富微生物源α-葡萄糖苷酶抑制剂的来源,开发食用降糖产品。方法:采用4-硝基酚-α-D吡喃葡萄糖苷(p-nitrophenyl-α-D-glucopyranoside,p-NPG)方法从酒糟中筛选产α-葡萄糖苷酶抑制剂能力较强的酵母菌,通过26S rDNA D1/D2区基因序列分析对其进行鉴定,并以α-葡萄糖苷酶抑制率为评价指标,利用单因素试验及正交试验对其进行发酵条件优化。结果:获得1株产α-葡萄糖苷酶抑制剂能力较强的酿酒酵母(Saccharomyces cerevisiae),编号为sg_093,该菌株产α-葡萄糖苷酶抑制剂最佳发酵条件为以3 g/100 mL葡萄糖为碳源、1 g/100 mL酵母抽提物为氮源、初始pH值为7.0、接种量1.5%、温度20℃下发酵48 h,所得发酵液的α-葡萄糖苷酶抑制率为66.0%,是优化前的1.5倍,并且是以可逆混合竞争方式抑制α-葡萄糖苷酶。结论:获得1株酿酒酵母,其发酵产物对α-葡萄糖苷酶活性有较好的抑制作用。

Objective:Screening theα-glucosidase inhibitor producing yeast,which is rich in microbial sources ofα-glucosidase inhibitor,to develop food hypoglycemic products.Methods:Through the screening of yeast in the fermentation process of wine,a strain of yeast with strong capacity of producingα-glucosidase inhibitor was obtained by p-nitrophenyl-α-D-glucopyranoside(pNPG)method,identified by 26S rDNA D1/D2 gene sequence analysis,and the fermentation conditions were optimized by single factor test and orthogonal test,taking the inhibition rate ofα-glucosidase as the evaluation index.Results:The Saccharomyces cerevisiae with high yieldα-glucosidase inhibitor was obtained and was named sg_093.The optimal fermentation conditions by the strain were 3 g/100 mL glucose as carbon source,1 g/100 mL yeast extract as nitrogen source,initial pH 7.0,inoculum 1.5%,temperature 20℃,and time 48 h.Under the optimized conditions,the inhibition rate ofα-glucosidase inhibitor reached 66.0%,which was 1.5 times that of before optimization.And inhibitingα-glucosidase in a mixed competitive manner.Conclusion:The strain Saccharomyces cerevisiae was obtained and its fermentation products had a good inhibitory effect onα-glucosidase activity.