Effects of six commercially available koji (Chinese Xiaoqu) on the production of ethyl acetate, ethyl lactate, and higher alcohols in Chinese Baijiu (distilled spirit) brewing.

Commercial koji has been increasingly used in Chinese Baijiu brewing; however, there are only few studies comparing different koji and their relationship with key components of Chinese Baijiu such as ethyl acetate, ethyl lactate, and higher alcohols. Here, we studied six commercially available koji and showed that the microbial communities in the individual koji varied in composition, with , , and primarily associated with starch hydrolysis and mainly associated with alcohol production. In the brewing processes using the six koji, was undoubtedly the most abundant fungus and , , and were the predominant bacterial groups.