Effects of Main Nutrients on Glucoamylase and Protease Activity Produced by Aspergillus Niger

The effects of some medium components,including culture medium proportions and several simple carbon sources,on protease and glucoamylase activity of aspergillus niger were investigated.The results show that among two kinds of organic nitrogen sources soybean meal could be used efficiently by aspergillus niger,the optimal conditions of culture medium for enzyme secretion was the mass ratio of wheat bran and soybean meal of 5∶5 and the glucoamylase activity of 1 185 U/g,when the cultivating condition was 20 g medium in 250 mL flask and incubation temperature of 30 ℃ for 72 hours.The protease activity had no obvious difference among the three samples.The glucoamylase activity was most when the glucose of 0.5% and sucrose of 0.75% were added in the basic medium respectively.The glucoamylase activity increased with the increasing of starch concentration.The protease activity and spore yield were closely correlated with the kind,concentration of carbon sources and growth of aspergillus niger.