2021 Volume 72 Issue 5 Pages 243-250
Compared to solid koji, it's easier to control culture using liquid koji of Aspergillus kawachii. However, because acid-resistant α-amylase (ASAA) activity is low, this study aimed to investigate enhancement of ASAA activity by liquid koji. Aspergillus kawachii NBRC4308 is used for the strain. The strain was inoculated into a basal liquid medium modified from the SLS liquid medium, and cultured at 30℃ and 200 rpm for 72 hours. When rice or barley was cultured as a culture substrate, ASAA activity was enhanced to 13.4 U/mL or 23.7 U/mL by adding 2.0 g or 3.0 g of skim milk and 5.1 g or 3.4 g of sesame, respectively, to 100 mL of medium. Furthermore, the ASAA activity was enhanced by the phosphate and the insoluble fraction of sesame. Since ASAA activity in this study was higher than other previous studies, new liquid koji products are expected to be developed.
