纳豆菌产糖苷酶的发酵工艺优化

目的:优选纳豆菌产糖苷酶的发酵工艺.方法:采用TLC检测发酵后纳豆中大豆异黄酮变化情况.以酶活力为指标,在单因素试验基础上,通过正交试验考察发酵时间、加水量、接种量、初始pH对发酵工艺的影响.结果:TLC确定使用纳豆菌产的糖苷酶为胞内酶.最佳发酵工艺为发酵时间36 h,加水量70％,接种量10％,初始pH7.5,酶活力达205 U·mL-1.结论:大豆异黄酮经纳豆菌发酵能由糖苷形式转化为苷元形式,纳豆菌所产的胞内酶转化染料木苷为染料木素的酶活力高于胞外酶.

Optimization of Fermentation Technology of Bacillus Natto Producing Glycosidase

Objective: To optimize fermentation technology of bacillus natto producing glycosidase. Method: Conversion of isoflavones in fermented natto was analyzed by TLC.With enzyme activities as index,based on single factor test,effect of fermentation time,the amount of water,inoculum size and initial pH on fermentation technology was investigated by orthogonal test. Result: Glycosidase produced from natto was determined as intracellular by TLC.Optimum fermentation technology was as following:fermentation time 36 h,the amount of water 70%,inoculum size 10%,initial pH 7.5.Enzyme activities was up to 205 205 U·mL^-1 under these conditions. Conclusion: After fermented by bacillus natto,isoflavones could be aglycone from glycosidic,intracellular enzyme producing from bacillus natto showed higher enzyme activities than extracellular for transforming genistin to genistein.