Abstract:  Wheat bran, maze flour and water(1:1)were mixed into the solid medium, and then sterilized (121℃,30min). The solid medium was inoculated in 3% WD201 strain, fermented at 30℃ for 5days, while β-glucosidase in the fermented medium was extracted with buffer liquid. The common nitrogen elements and 2.5% lactate had no effect on metabolism of WD201 strain which secretedβ-glucosidase. The purifiedβ-glucosidase showed the optimum catalysis conditions were: 30℃ and pH4.4～ 4.8 for 30min. The soybean isoflavone glucoside in soybean bran was extracted with 60% alcohol contained 2% CaCO3 at 50℃, then the interferential constitutents were extracted with petroleum ether and chloroform, and the isoflaovne glucoside in water phase were extracted with butanol. The isoflavone glucoside in butanol in special silica gel column were eluated again with acetone. The isoflavone glucoside was hydrolyed into pure isoflavones withβ-glucosidase at the optimum enzyme conditions, and protein and glucose were extracted through superfilter and processed by immobilized cell fermentation.

Key words: soybean isoflavones, two steps operation, operation unit