Response and assembly of abundant and rare taxa in Zaopei under different combination patterns of Daqu and pit mud: from microbial ecology to Baijiu brewing microecosystem

Abstract

The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu, pit mud (PM), and the interaction of both. However, little is known about how their combination patterns affect the microbiome and metabolome of Zaopei, especially the metabolic function of rare taxa. Here, an experiment on industrial size was designed to assess the effects of 6 combinations (3 kinds of Daqu × 2 kinds of PM) on the composition and assembly of different taxa, as well as the flavor profile. The results showed that Zaopei's microbiota was composed of a few abundant taxa and enormous rare taxa, and rare bacterial and abundant fungal subcommunities were signifi cantly affected by combination patterns. The assembly processes of abundant/rare taxa and bacterial/fungal communities were distinct, and environmental changes mediated the balance between stochastic and deterministic processes in rare bacteria assembly. Furthermore, specifi c combination patterns improved the fl avor quality of Zaopei by enhancing the interspecies interaction, which was closely related to rare taxa, especially rare bacteria. These fi ndings highlighted that rare bacteria might be the keystone in involving community interaction and maintaining metabolic function, which provided a scientifi c foundation for better understanding and regulating the brewing microbiota from the viewpoint of microbial ecology.

Characterizing the Contribution of Functional Microbiota Cultures in Pit Mud to the Metabolite Profiles of Fermented Grains

“…The TCA cycle, essential for aerobic respiration, plays a vital role in providing energy and nutrition for microbial growth and is primarily influenced by Abundant fungi . Meanwhile, the metabolism of the butyric acid pathway was strongly associated with the bacterial RT [ 4 ].…”

“…Daqu is an essential starter and one of the requisite raw materials in Baijiu brewing [ 3 ]. In fact, the contribution of the microbiota habituated in Daqu to the yield and quality of the fresh Baijiu still depended on the interaction with PM [ 4 ]. Previous studies revealed the synthesizing of some organic acids was driven by the synergistic effect of microbiota habiting in both FG and PM during the process [ 5 ].…”