配糟对清香型白酒发酵中环境因子及微生物群落的影响

Effects of distilled grains on environmental factors and microbial communities in the fermentation of light flavor Baijiu

摘要:

【背景】环境因子是影响微生物生长代谢的重要因素，解析半开放条件下酿造过程中环境因子对微生物群落演替的作用对于清香型白酒生产调控具有重要意义。配糟在白酒发酵过程中起着调节发酵速度的作用，其对微生物群落组成变化的影响尚不明确。【目的】揭示使用不同发酵周期配糟对清香型白酒发酵过程中环境因子及微生物群落演替的影响。【方法】采用PacBio测序平台和多元统计分析比较使用2种配糟酒醅中微生物群落结构组成，结合蒙特卡洛置换检验明确环境因子对微生物群落的影响。【结果】与使用正常发酵周期配糟酒醅相比，使用延长发酵周期配糟酒醅水分较低，而酸度、氨基酸态氮、总游离氨基酸、还原糖和残余淀粉较高；微生物多样性和丰富度分析发现，使用延长发酵周期配糟酒醅中细菌α多样性极显著高于使用正常发酵周期配糟酒醅（P<0.001），而真菌α多样性显著/极显著低于使用正常发酵周期配糟酒醅（P<0.05，P<0.001）；通过组间差异性分析发现，细菌群落共产生28个差异指示种，而真菌群落共产生15个差异指示种；水分、酸度、氨基酸态氮、还原糖、残余淀粉和总游离氨基酸对微生物群落结构的影响显著（P<0.05），其中水分、酸度、氨基酸态氮和总游离氨基酸与使用延长发酵周期配糟酒醅微生物群落密切相关，还原糖和残余淀粉是使用正常发酵周期配糟酒醅微生物群落演替的主要驱动因素。【结论】本研究揭示了使用不同发酵周期配糟的清香型白酒发酵过程中环境因子对微生物群落组装的驱动作用，为清香型白酒的可控发酵提供了理论基础。

Abstract:

[Background] Environmental factors affect the microbial growth and metabolism. Therefore, understanding their influences on microbial community succession in the semi-open fermentation process is of great significance for the production regulation of light flavor Baijiu. Distilled grains play a role in regulating the fermentation speed of Baijiu, while their effects on microbial community succession are still unclear. [Objective] To reveal the effects of distilled grains fermented for different time periods on the environmental factors and microbial community succession during light flavor Baijiu fermentation. [Methods] The high-throughput sequencing on PacBio platform and multivariate statistical analysis were performed to reveal the microbial community structures in two different groups of fermented grains. Monte Carlo permutation tests were conducted to determine the effects of environmental factors on microorganisms. [Results] The fermented grains prepared with distilled grains produced in extended fermentation period (EG) had lower water content and higher acidity, amino acid nitrogen, total free amino acids, reducing sugar, and residual starch than those prepared with distilled grains produced in normal fermentation period (NG). The fermented grains with EG had higher bacterial alpha diversity (P<0.001) and lower fungal alpha diversity than those with NG (P<0.05, P<0.001). A total of 28 differential bacterial indicator species and 15 differential fungal indicator species between groups were identified. Water content, acidity, amino acid nitrogen, reducing sugar, residual starch, and total free amino acids had effects on the microbial community structure (P<0.05). Among them, water content, acidity, amino acid nitrogen, and total free amino acids were associated with the microbial community of fermented grains with EG, and reducing sugar and residual starch were the main driving factors for the microbial community succession of fermented grains with NG. [Conclusion] The effects of environmental factors on microbial community assembly in the fermentation process of light flavor Baijiu with distilled grains produced in different fermentation periods were revealed, laying a foundation for the controlled brewing of light flavor Baijiu.