Influence of the Residual Mature Qu’s Bacterial Community Structure on Box Wheat Qu–Making Process for Shaoxing Rice Wine (Huangjiu)

In this study, we aimed to use high-throughput sequencing technology to systematically analyze the bacterial community structure during the box wheat Qu–making process to understand the succession of bacterial communities. To our knowledge, this is the first study in which mature Qu, raw materials, and the complete fermentation process of the box wheat Qu were analyzed. Significant differences in the distribution and abundance of the dominant bacteria were observed among these samples. Bacterial diversity was lowest in residual mature Qu, gradually increasing after moistening and fermentation and declining after reaching its peak on the fourth day. The predominant bacteria observed in residual mature Qu were Saccharopolyspora (81.64%), Weissella (3.39%), and Staphylococcus (3.06%). The most abundant bacteria in the moistened material were Pantoea (48.50%), Staphylococcus (12.10%), and Saccharopolyspora (11.61%). However, a rapid decline in Pantoea and Staphylococcus in box wheat Qu was observed on the first day of fermentation. Following fermentation, the most abundant bacteria were Saccharopolyspora (68.85%), Bacillus (19.94%), and Thermoactinomyces (4.70%). Nonmetric multidimensional scale and linear discriminant analysis effect size analyses revealed a significant difference in the bacterial community structure between the raw materials and samples obtained at the end of fermentation. These findings underscore the significant effect of the bacterial community structure of residual mature Qu on box wheat Qu.