Exploring the mechanism of regulating the microbial community and metabolizing trait in Chinese Baijiu fermentation via Huizao

In the traditional fermented food processes, inoculating the solid or semi-solid cultures of the last batch to the fresh matrix (Huizao) for initiating the fermentation or regulating the niches is an applied technology widely. Revealing the effect of this operation on the driving microbial community assembly is a prerequisite for improving the productivity of fermentations on-scale. Despite a plethora of research performed, the factors assembling the microbial communities remain unclear. Here, Chinese Xiaoqu Jiu fermenting was used as a model to explore the mechanism regulating the community assembly and their metabolism during the process via Huizao. Results indicated Huizao effectively regulated the hydrolysates concentration and trophic network in the fermenting grains of the fresh batch, driving the community and their metabolites to assemble rapidly. Therefore, the metabolites were stabilized stepwise with the batches, the similar networks of microbes and metabolites were formed. These results suggested that microbial self-domestication was closely related to the kinds and contents of organic acids, diluting hydrolysates concentration, and uncovered the mechanism of Huizao adjusting the community and metabolites stability by polyphase analyzing approaches. This laid down a theoretical foundation for the optimization and predictively traditional fermentations in the industry.