基于多组学技术的鲁氏酵母菌响应盐胁迫的分子基础及对四川豆瓣酱发酵的影响机制

Salt stress is an environmental condition commonly encountered during the fermentation of high-salt foods, which seriously impair the physiological functions of cells and efficiency of food manufacture. In this study, Z. rouxii CGMCC3791 was used as the initial strain, and the molecular basis of salt stress response and the physiological mechanisms of Sichuan horse-bean paste fermentation augmented by Z. rouxii were investigated. The differences in intracellular micro-environment (intracellular pH, activities of key enzymes, co-factors and redox levels), cell membrane characterization (distribution of fatty acids, membrane fluidity), gene transcription, protein expression, and cellular metabolism under different salt concentrations were revealed based on physiological and multi-omics analyses to elucidate the physiological responses and regulatory mechanisms of Z. rouxii during salt stress. In addition, effect of Z. rouxii augmentation on the fermentation of Sichuan horse-bean paste was examined by investigated the microbial community, flavor compounds of paste and the relationship between microbial community structures and flavor compounds. These results may contribute to elucidate the salt tolerance mechanisms of Z. rouxii and the brewing mechanisms of Sichuan horse-bean paste, and lay the foundations for the directed regulation and revealing the flavor-forming mechanisms of fermented food.

盐胁迫是高盐发酵食品生产中广泛存在的一种环境胁迫，严重影响细胞生理功能和食品发酵的效率。本课题以鲁氏酵母菌CGMCC3791为研究对象，研究其响应高盐胁迫的分子基础及强化四川豆瓣酱发酵的生理机制。分别从细胞生理特性和多组学分析角度研究细胞在不同盐浓度条件下胞内微环境(胞内pH、关键酶活性、辅因子及氧化还原水平)、细胞膜生理特性(膜脂肪酸组成、膜流动性)、基因转录水平、蛋白表达水平、细胞代谢水平上的差异，全面系统阐释鲁氏酵母菌盐胁迫条件下的生理应答和调控机制。同时考察了鲁氏酵母菌生物强化对四川豆瓣酱发酵的影响，从酱醅微生物群落结构、风味组分及相互关系方面揭示鲁氏酵母菌强化四川豆瓣酱发酵的生理机制。研究结果有助于深入理解鲁氏酵母菌耐盐生理机制和四川豆瓣酱酿造机制，从而为发酵食品的定向调控和风味形成机理的解析奠定理论基础。

鲁氏酵母菌是四川豆瓣酱发酵过程中重要的功能菌株，盐胁迫是其酿造过程中面对的主要环境胁迫，严重影响细胞生理功能和食品发酵的效率。本项目利用微生物生理学和系统生物学的手段全面系统揭示了鲁氏酵母菌在盐胁迫条件下的应激响应，揭示其适应高盐胁迫的生理机制；结果表明，鲁氏酵母菌通过改变胞内微环境(胞内pH、关键酶活性、辅因子及氧化还原水平)、细胞膜生理特性(膜脂肪酸组成、膜流动性、膜完整性等)以及调控关键基因、蛋白的表达和代谢物的积累等方式适应高盐胁迫。提出了基于热预适应和外源添加脂肪酸等方式提高细胞盐胁迫抗逆的方法，显著改善了鲁氏酵母菌对盐胁迫以及其他环境胁迫的耐受性能。同时利用生物强化的方式，考察了鲁氏酵母菌对四川豆瓣酱发酵的影响，结果表明，鲁氏酵母菌通过改变酱醅微生物群落结构、微生物互作以及风味组分等方式强化四川豆瓣酱发酵过程。研究结果对于深入理解鲁氏酵母菌耐盐生理机制和强化四川豆瓣酱酿造机制，从而为发酵食品的定向调控和风味形成机理的解析奠定理论基础。