High throughput sequencing of fermented grains
Ethyl acetate is the characteristic aroma substance in light-flavor Baijiu, and its low level in fermented grains can reduce the quality of distilled Baijiu. Biofortification of Baijiu fermentation using indigenous functional strains is an effective method to stabilize the quality of Baijiu by altering the microbial community structure and flavor metabolism of the fermentation ecosystem. This study focused on examining the effects of Jiuqu fortified with a high glucoamylase activity-producing Saccharomycopsis fibuligera Y162 on microbial communities, physicochemical parameters, and volatile profiles throughout the fermentation of LFB. The results showed that the ethyl acetate content significantly increased in the original liquor and fermented grains, and the fungal community was significantly altered. PacBio single-molecule real-time sequencing analysis indicated that Lactobacillus helveticus, Rhizopus sp., Saccharomyces cerevisiae, and Issatchenkia orientalis emerged as the dominant species at the end of fermentation. Co-occurrence analysis showed that ethyl acetate was significantly related to the I. orientalis and Rhizopus sp. (the main fungal biomarkers), which was driven by the functional S. fibuligera. Mantel test showed that acidity, temperature, and moisture were the main physicochemical factor affecting microbial communities . To summarize, biofortification with S. fibuligera exhibited positive effects in enhancing typical flavor metabolites by influencing fungal community structure in LFB. These findings imply that promising potential for the application of the indigenous strain in improving the quality of Baijiu.