乳酸菌在黄酒等酵母-乳酸菌混合发酵体系中具有重要作用，提供酸性环境并促进风味物质合成。申请人前期发现融合魏斯氏菌是黄酒酿造过程的核心乳酸菌，可显著促进黄酒特征风味物质-脂肪酸乙酯（FAEE）的合成并且其代谢产物-乳酸起到关键作用，但其影响FAEE合成的调控机制尚不清晰。本项目利用CRISPR-Cas9技术构建不同产乳酸能力的融合魏斯氏菌突变株，考察突变株在黄酒酿造中的适应性变化。在黄酒混合发酵体系中，考察融合魏斯氏菌产乳酸能力差异对FAEE形成的影响；在黄酒膜分离耦合发酵系统中，利用比较代谢组学和转录组学考察融合魏斯氏菌产乳酸能力差异对酵母代谢功能及FAEE合成通路的影响，鉴定FAEE合成关键基因并验证其对突变株产酸能力变化的敏感性。最终阐明融合魏斯氏菌影响黄酒FAEE合成的调控机制，为建立黄酒特征风味组分的微生物代谢调控方法提供理论基础，对提升黄酒风味品质具有重要意义。

Lactic acid bacteria (LAB), which provide an acidic environment and promote the synthesis of flavor compounds in wine, playing an important role in the wine (such as Huangjiu) fermented by mixed yeast and LAB. In our previous study, Weissella confusa was found to be the core LAB during Huangjiu brewing. W.confusa could significantly promote the synthesis of fatty acid ethyl esters (FAEE), a characteristic flavor compounds in Huangjiu. Lactic acid, the metabolite of W.confusa playing a crucial role in the promotion. However, regulation mechanism of W.confusa influencing the synthesis of FAEE is still not clear. In current study, CRISPR/Cas9 technology will be applied on W.confusa to prepare strains with different lactic acid-producing ability, and adaptability of the mutant strains during Huangjiu brewing will be investigated. In mixed fermentation system of Huangjiu, effect of W.confusa mutant strains on the synthesis of FAEE during wine brewing will be studied. In membrane separation coupled fermentation system, effect of W.confusa mutant strains on metabolic function and FAEE synthetic pathways of Saccharomyces cerevisiae F23 will be revealed by using comparative metabolomics and transcriptomics techniques. Besides, the key genes of FAEE synthesis in F23 will be identified and its sensitivity to lactic acid-producing ability of the mutant strains also will be verified. Collectively, the mechanism of W.confusa influencing FAEE synthesis in Huangjiu will be clarified. This study can provide a theoretical basis for the establishment of microbial metabolism control methods for the characteristic flavor components of Huangjiu, and is of great significance for improving the flavor quality of Huangjiu.