Study on the Optimization of the Fermentation Medium of β-glucosidase Produced by Aspergillus Niger

β-glucosidase was produced by solid fermentation of Aspergillus niger and the fermentation medium was optimized by single factor experiments as follows: the ratio of wheat bran and rice straw powder was 1∶1,the ratio of solid(bran straw powder) and liquid(nutrient solution) was 1∶2,pH value of nutrient solution was 4.44,2 % ammonium sulphate used as nitrogen source,0.1 % Tween 80 used as surfactant,metal ion was 1 μmol Mn2+,the inducer was 0.1 % rhamnose.Under the above conditions,the enzyme activity of β-glucosidase was superior.