乳酸菌是食品混菌发酵体系中广泛存在的一类微生物，它们对改善食品结构、风味物质合成、平衡菌群和抑制杂菌的生长具有重要的作用和影响。然而，由于食品混菌发酵体系的复杂性和乳酸菌的多样性，目前还没有实现对体系中乳酸菌的全面功能解析和与食品组分合成与代谢及与其它微生物相互作用关系的系统关联分析。本项目采用宏基因组测序和实时定量PCR结合的方法揭示酱油发酵过程酱醪中乳酸菌的组成和数量变化规律；采用基于比较基因组的分析方法对酱醪中优势乳酸菌和特征乳酸菌耐受环境胁迫能力和与酱油发酵相关功能进行解析；揭示乳酸菌与酱油发酵过程中风味物质形成以及它们与其它微生物之间的相互作用关系的关联性。研究结果对阐明食品混菌发酵机理，保证发酵食品品质的稳定性和安全性，以及定向强化发酵食品中的特定组分具有重要意义，并可为研究其它类型混菌体系中特定微生物的功能提供研究思路。

Lactic acid bacteria (LAB) is a representing bacteria in a diverse bacterial community in many types of fermented foods. They contribute to texture change of food or raw materials, nutrients improvement, additional characteristic flavor and aroma, and has the impact on compounds metabolism and microbial interactions. The specific function of LAB and the connection with other commensals is still unclarified due to the complexity of bacterial community and diversity of lactic acid bacteria in fermented foods. This proposal targets on investigation of the dynamic composition and quantity of LAB in soy sauce moromi during fermentation through metagenome sequencing and real-time quantitative PCR analysis. Comparative genome analysis of the dominant LAB and specific LAB will be performed to discover their adaption to stress and effect on soy sauce fermentation. In addition, the connections between LAB biochemical and biological properties and soy sauce fermentation, as well as and the interaction of LAB with other commensals in the moromi will be investigated. Results and discoveries of this project turns to be the key basis in finding solutions for studying microbes in a complex bacterial community.