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.