中国白酒发酵过程中的核心微生物群及其与环境因子的关系

【目的】揭示白酒酿造过程复杂微生物群落中的核心微生物群(core microbiota),定量分析核心微生物群的环境调控因素。【方法】通过高通量测序揭示发酵过程中的微生物群落结构,使用气相色谱-质谱联仪(GC-MS)测定发酵过程中的挥发性化合物。采用微生物群落与挥发性化合物轮廓关联分析获得风味代谢的功能微生物群(functional microbiota);通过微生物共现性网络分析,获得群落组成中的共现微生物群(co-occurring microbiota),两类微生物群的集合即为白酒酿造的核心微生物群。利用冗余分析(redundancy analysis)和蒙特卡洛置换检验(Monte Carlo permutation test)研究每个环境因素对该核心微生物群的影响。【结果】白酒发酵过程中的核心微生物群主要包含10个属,分别是Lactobacillus、Saccharomyces、Candida、Rhizopus、Saccharomycopsis、Pichia、Dipodascus、Bacillus、Thermoascus和Lactococcus。冗余分析和蒙特卡洛置换检验表明,化学因素(还原糖和乙醇)对核心微生物群的变化比物理因素(水分、温度和酸度)具有更加重要的影响作用,此外物理-化学因素的相互作用对核心微生物群的驱动也有很大的影响。【结论】本研究揭示了白酒发酵过程中的微生物群落组成和代谢物轮廓的变化规律及其二者之间的相关关系,确立了发酵过程中的核心微生物群并量化了影响核心微生物群变化的环境因素,为实现合成微生物组生产白酒及其定向调控奠定理论基础。

Core microbiota in Chinese liquor fermentation and associations with environmental factors

Objective] The aim of this study is to reveal core microbiota during Chinese liquors fermentation, and to quantify the impact of environmental factors on the variations of the core microbiota.Methods] The microbial community composition was characterized by high-throughput sequencing. The volatile compounds were analyzed by gas chromatography-mass spectrometry. Core microbiota was defined according to the microbial function and microbial correlation patterns using the microbe-metabolite correlation approach and co-occurrence network analysis. We used redundancy analysis and Monte Carlo permutation test to analyze the influence of environmental factors on the core microbiota.Results] The core microbiota during the liquor fermentation consisted of Lactobacillus, Saccharomyces, Candida, Rhizopus, Saccharomycopsis, Pichia, Dipodascus, Bacillus, Thermoascus and Lactococcus. The variations of the core microbiota were mainly affected by the chemical factors such as reducing sugar and ethanol. In addition, the interaction between physical and chemical factors was also substantial for the core microbiota variations.Conclusion] This study disentangled the relationship between microbial communities and metabolites, found out the core microbiota in the liquor fermentation process, and quantified the influence of environmental factors on the variations of core microbiota, hence providing a theoretical perspective for regulating the production of liquors by using synthetic microbial communities or by controlling environmental factors.