Temporal dynamics of abundant and rare microbial communities in fermented grains during Chinese light-aroma Baijiu fermentation

Bin LinWei JiangJie TangQun LiRui LiLiping ZhuFan ZhangShengzhi YangQiang YangShenxi Chen^*

• Jing Brand, Daye, China

Chinese Baijiu fermentation process involves a complex multi-species microbial community including abundant and rare taxa. However, the rare and abundant microbes in fermented grains during Baijiu fermentation are poorly understood. In this study, we investigated the succession of abundant and rare microbial communities during Chinese light-aroma Baijiu (LAB) fermentation using Illumina MiSeq and PacBio sequencing platform. Our results showed that a total of 78 rare genera and 24 abundant genera were identified in the bacterial community, while 135 rare genera, 30 abundant genera, and 2 moderate genera were detected in the fungal community during the LAB fermentation. Abundant and rare microbial taxa showed significant differences in microbial diversity and taxonomic composition during two consecutive fermentation stages. At the later stage of grain fermentation, Lactobacillus, Saccharomyces, and Condenascus emerged as the dominant abundant genera. Unlike bacterial rare taxa, fungal dominant rare genera including Cladosporium, Saitozyma, Russula, Alternaria, Oidiodendron, and Chaetomium had an increasing trend throughout the fermentation process. Molecular ecological network analysis indicated that rare taxa, which accounted for more than 50% of keystone OTUs, played a key role in maintaining the structure of microbial community in fermented grain, and bacterial network showed lower complexity than fungal network at the late stage of grain fermentation. Moreover, the assembly of rare and abundant microbial communities was governed by stochastic processes. This study provides new insights for understanding the dynamic succession of abundant and rare taxa during LAB fermentation and improving the quality and controllability in Baijiu production.