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 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 potato dextrose agar. The mycelium development of A. oryzae S. was observed by scanning electron microscope. During koji production, pH of soybean koji increased from 6.32 to 6.07. It was caused by extracellular proteins production. The highest neutral protease, alkaline protease and amylase activities were 84.38, 41.35 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.

Index Terms—Amylase, Aspergillus oryzae S., protease, soybean koji

Chuenjit Chancharoonpong is with the Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan and Kasetsart University, Bangkok 10900, Thailand (e-mail: csncjc@ku.ac.th).
P. C. Hsieh and S. C. Sheu are with the Department of Food Science, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan (e-mail: pchsieh@mail.npust.edu, ssheu@mail.npust.edu.tw).

Cite: Chuenjit Chancharoonpong, Pao-Chuan Hsieh, and Shyang-Chwen Sheu, "Production of Enzyme and Growth of Aspergillus oryzae S. on Soybean Koji," International Journal of Bioscience, Biochemistry and Bioinformatics vol. 2, no. 4, pp. 228-231, 2012.