低温大曲微生物群落种间相互作用机制的研究

As a traditional fermentation starter, Daqu is resource rich in microorganisms. The metabolites, produced by microbial interaction in Daqu, are essential elements that give Chinese liquor (Baijiu) and vinegar the special flavor and taste. Since thousands of years, Daqu has had a great reputation both in China and abroad and been using as an agent in saccharificating and fermenting during the production of vinegar and Chinese liquor. In this proposal, culture-dependent methods and metagenomic techniques will be used together to study changes in structure and function of the microbial community of low-temperature Daqu to identify dominant and functional microorganisms. In addition, the use of metabolomics and transcriptomics will help to analyze metabolite complexity and metabolic pathways of microbial community in low-temperature Daqu respectively. Thus, it may reveal the mechanism of metabolic interaction. Meanwhile, growth and quorum sensing signal of the microorganisms will be also monitored. Moreover, spatial structure of the microbial community will be observed by different microscopes to analysis the behavior of microbial community and social interaction mechanism in low-temperature Daqu community. The study can establish a model of microbial community for the research of interspecies interactions. And it can also get a deep insight into the effect of interaction mechanism on low-temperature Daqu microbial community. And it can improve the quality of low-temperature Daqu to promote the development of Chinese food fermentation industry.

大曲作为中国传统白酒和食醋的发酵剂蕴含着丰富的微生物资源，微生物通过相互作用而形成的菌系、酶系和物系是影响产品风味的关键因素，使其成为不可替代的糖化发酵剂而沿用至今。本项目在已有研究的基础上采用宏基因组学对低温大曲微生物群落的物种和功能丰度进行研究，探究主要功能微生物；用代谢组学方法对低温大曲群落复杂的代谢物组进行分析；转录组学方法对群落中的代谢通路进行推测，结合代谢物组分析，揭示低温大曲微生物群落中代谢性相互作用机制；同时监测群落中微生物的生长和群体感应信号因子，分析群落中微生物的群体行为，并利用多种显微镜观察大曲群落的空间结构特征，分析空间层面的群体行为，深入研究低温大曲微生物群落中群体性相互作用。通过研究，建立混合菌种微生物种间相互作用研究模型，深入分析相互作用机制对低温大曲微生物群落的影响，从而提高大曲的质量稳定性，推进行业发展。

大曲蕴含着丰富的微生物资源，微生物通过相互作用而形成的菌系、酶系和物系是影响发酵酒风味和口感的关键因素，使其成为不可替代的酿酒发酵剂而沿用至今。本项目采用宏基因组学对低温大曲微生物群落的物种和功能丰度进行研究，用代谢组学方法分析功能微生物代谢物组指纹图谱，确立主要功能微生物，包括芽孢菌属，横梗霉属、乳杆菌属、根霉属、明串珠菌属等；对于芽孢菌属内互作，地衣芽孢杆菌生长速率大于枯草芽孢杆菌和解淀粉芽孢杆菌，地衣芽孢杆菌环境适应性不如其他两株菌，且与其他两种菌共培养时生长受到抑制，在竞争中处于劣势。地衣芽孢杆菌与真菌共培养时，生长受到不同程度的抑制，米曲霉和伞枝横梗霉抑制作用较强，共培养可以代谢产生更多的糖类物质，二者相互促进大分子糖类物质的代谢，葡萄糖的量增加；乳杆菌细菌与酿酒酵母呈现出群体性相互作用造成的空间分布规律。在相互作用影响下，底层的乳酸菌生物量提高，环境适应能力提高，典型代谢产物浓度极低；顶层的酿酒酵母主导了代谢但生长受到抑制。其中通过结合核心功能微生物代谢性和群体性相互作用的类型和机制研究，建立混合菌种微生物种间相互作用研究模型，深入分析相互作用机制对低温大曲微生物群落的影响，从而提高大曲的质量稳定性，推进行业发展。