Bioaugmented Daqu-induced variation in community succession rate strengthens the interaction and metabolic function of microbiota during strong-flavor Baijiu fermentation

Abstract

Bioaugmented Daqu based on functional strains/microbiota inoculating improved the quality and yield of Baijiu, but the underlying mechanism remains unclear due to the lack of ecological insights into the complex and dynamic process. Hence, three kinds of Daqu were compared for fermentation, physicochemical parameters, community succession and flavor profile in fermented grains (Zaopei). Compared with the traditional Daqu, both two bioaugmented Daqu, namely space Daqu and fortified Daqu, sustained higher biodiversity by delaying the succession of bacterial community and accelerating that of fungal one, and Lactobacillus and Pichia were biomarkers of community succession rate. Ecological analysis indicated that the succession of bacterial communities was more sensitive to environmental parameters, in which lactic acid was closely related to its assembly pattern and niche breadth. In addition, bioaugmented Daqu contributed to achieving “ethyl hexanoate-increasing” and “ethyl lactate-decreasing”, which could be attributed to the enhanced interspecies interactions relieving the survival pressure of flavor producers, such as Kroppenstedtia, Saccharopolyspora, Pichia and Kazachstania. These results elucidate the mechanism of bioaugmented Daqu in regulating community and metabolism and highlight the vital role of community succession rate, which will guide the directional regulation of Baijiu fermentation in the future.