Conversion of soybean isoflavone in natto fermentation

Bacillus natto isolated from the traditional Japanese natto was used for the conversion of soybean isoflavone into soy isoflavone aglycone catalyzed by isoflavone-glucosidase.The conversion of the soybean isoflavone was determined and the optimum condition is: the temperature was 37 ℃,fermentation time was 2 d,pH=7.0,and the water content was 60%.Most of the soybean isoflavone were transformed into soy isoflavone aglycone under the better condition.