Effect of Different Combinations of Soybean and Wheat Bran on Enzyme Production from Aspergillus oryzae S

Abstract

To investigate the enzyme production from Aspergillus oryzae S. NPUST-FS-206-A1, different combinations of soybean and wheat bran (40%:60%, 50%:50%, and 60%:40% w/w) in koji were used as substrates in soybean koji fermentation. During cultivation period, pH change of various samples was similar. However, moisture content of koji obviously decreased. Koji with high content of soybean conducted high protease activity. After 48 h of cultivation, koji containing 60% soybean showed the highest neutral protease activity of 84.38 U/g dry weight. Sample with high amount of wheat bran presented high amylase activity of 731.53 U/g dry weight. Reducing sugar content of koji was related to amylase activity. Moreover, different inoculum sizes of A. oryzae S. spore had no effect on the enzyme production.