Succession and function analysis of microbial community during traditional broad bean paste fermentation

Abstract:

[Objective] This study aimed to analyze the succession of the microbial community and the changes of physicochemical metabolites during the fermentation of Chinese traditional broad bean paste, moreover, to explore the core functional microbiota that affects the flavor.[Methods] We used high-throughput sequencing to analyze the microbial community structure and succession, together, detected the physicochemical metabolites during the fermentation process. The correlations between the microbial community and physicochemical metabolites were also analyzed. Finally, core species were isolated from broad bean paste with clearly evaluated functional characteristics.[Results] The community structure changed significantly in the early stage of fermentation, and gradually stabilized in the mid-late stage. The dominant bacteria were Staphylococcus, Bacillus and Weisiella, among which Staphylococcus showed an upward trend during the whole fermentation, while Bacillus and Weisiella both showed a downward trend. The fungal community structure was relatively simple and stable, with average abundance of Aspergillus accounted for more than 97% of the total fungal community, and Zygosaccharomyces increased during the mid-late stage and then declined. Correlation analysis and in vitro functional validation showed that functional microbes (Aspergillus oryzae, Bacillus subtilis, Staphylococcus gallinarum, Weisiella confusa and Zygosaccharomyces rouxii) played different key roles in different fermentation stages.[Conclusion] In the early stage of fermentation, Aspergillus oryzae and Bacillus subtilis secreted enzymes to degrade macromolecular substances. Aspergillus oryzae, Staphylococcus gallinarum and Weisiella confusa resulted in acidification and amino acid production of broad bean paste, while salt-tolerant Zygosaccharomyces rouxii were essential for the formation of flavor substances in mid-late stage of fermentation.