Analysis of the effect of rice wine koji on the fermentation quality of rice wine based on high-depth sequencing

Rice wine koji is made from "ChengQu" as the parent species and is prepared by enriching microorganisms in the environment, which plays a decisive role in the formation of quality rice wine. This study explored the microbiome of 18 rice wine koji collected from Xiaogan, Fangxian, Hubei, Dazhou, and Sichuan and analyzed the sensory quality and microbiome of rice wine made with rice koji as a fermentation agent. Although our results showed that there were large differences in microbial communities and functions in rice wine koji, samples from the same region had a higher similarity, and the closer the distance, the higher the similarity. Five suspected new species (Lactococcus sp., Weissella sp., Lactobacillus sp., and Acetobacter sp.) were discovered by ultra-high-depth metagenomic sequencing; their functional maps and phase correlation analysis showed that they contributed positively to the aroma of rice wine. The sensory quality and microbial community structure of rice wine fermented with different rice wine koji have obvious differences, consistent with the structural difference of microorganisms in rice wine koji in different regions. These findings indicate that rice wine koji directly determines the structure of microorganisms in rice wine and directly or indirectly affects the sensory quality of rice wine.