Screening,Fermentation Conditions Optimization and Enzymatic Kinetics of α-Glucosidase Inhibitor-Producing Yeasts
Objective:Screening the α-glucosidase inhibitor producing yeast,which is rich in microbial sources of α-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 of α-glucosidase as the evaluation index.Results:The Saccharomyces cerevisiae with high yield α-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 of α-glucosidase inhibitor reached 66.0％,which was 1.5 times that of before optimization.And inhibiting α-glucosidase in a mixed competitive manner.Conclusion:The strain Saccharomyces cerevisiae was obtained and its fermentation products had a good inhibitory effect on α-glucosidase activity.
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