传统豆瓣酱微生物群落发酵演替规律及其功能分析

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

摘要:

[目的] 解析中国传统豆瓣酱发酵过程中的微生物群落演替规律和理化代谢物质变化，探讨不同发酵阶段影响豆瓣酱风味的核心功能微生物。[方法] 采用高通量测序解析豆瓣酱发酵过程中的微生物群落结构和演替，并跟踪检测发酵过程中的理化代谢物质，然后分析微生物群落和理化代谢物质变化之间的相关性，最后在体外分离核心微生物并对其功能特性进行验证。[结果] 细菌和真菌群落结构在发酵前期显著变化，并在中后期逐渐趋于稳定。优势细菌主要是Staphylococcus、Bacillus和Weisiella，其中Staphylococcus在整个发酵过程中呈上升趋势，而Bacillus和Weisiella呈下降趋势。真菌群落结构较为简单且稳定，其中Aspergillus在整个发酵过程中的平均丰度占真菌总群落的97%以上，Zygosaccharomyces呈先上升后下降的趋势。相关性分析和体外功能验证表明，功能微生物（Aspergillus oryzae、Bacillus subtilis、Staphylococcus gallinarum、Weisiella confusa和Zygosaccharomyces rouxii）在不同发酵阶段发挥着不同的关键作用。[结论] 在成曲和发酵前期Aspergillus oryzae、Bacillus subtilis分泌各种酶来降解大分子物质，Aspergillus oryzae、Staphylococcus gallinarum和Weisiella confusa导致了酱醅的酸化和氨基酸的生成，而耐盐的Zygosaccharomyces rouxii在发酵中后期对风味物质的形成起重要作用。

关键词:中国传统豆瓣酱;高通量测序;微生物群落结构;功能微生物

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.

Key words:Chinese traditional broad bean paste;high-throughput sequencing;microbial community structure;functional microbiota