Enzyme Production and Growth of Aspergillus oryzae S. on Soybean Koji Fermentation

Abstract

Soybean koji is an important ingredient for traditional fermented food in South-East Asia and East Asia. It provides large amount of enzyme from koji mold, Aspergillus oryzae S., to digest nutrients in substrates. This study was aimed at production of certain enzymes in soybean koji and potential to be applied for accelerating fish sauce fermentation. Koji containing 60% soybean was used as substrate to investigate the enzyme production by A. oryzae S. The growth of this mold was enumerated by scanning electron microscope. During koji fermentation, pH increase of soybean koji was caused by enzymes production. The highest protease and amylase activities were 84.38 and 200 unit/g of dry weight, respectively. Moreover, growing of enzyme activities on soybean koji correlated with the growth of this mold. Electron micrograph showed that spores of A. oryzae S. were formed after 48 h of cultivation period. Additionally, the highest enzymes activities were also shown in this stage.