短双歧杆菌生物转化共轭亚油酸的分子机理及调控机制

共轭亚油酸（CLA）是从亚油酸衍生出的一类共轭双烯酸异构体的总称。常用化学法合成的CLA产物组成复杂且难以得到单一活性异构体，而乳酸菌能产具免疫调节活性的c9,t11-CLA异构体，因此利用生物法选择性合成CLA活性异构体已成为该领域的研究热点。目前双歧杆菌是已知CLA转化效率最高的微生物，但其转化机理与调控机制尚不清楚。本项目以一株c9,t11-CLA转化率达89%的短双歧杆菌为研究对象，结合基因组学与分子生物学手段，从亚油酸异构酶基因组成与功能以及生物转化通路进行分析，解析其生物转化CLA的分子机理；并运用代谢组学、转录组学等方法，从代谢物积累、基因转录等水平，阐明其生物转化CLA的调控机制，为将乳酸菌遗传改良使其适用于工业化生产CLA提供指导，也为短双歧杆菌的应用奠定重要的物质基础和理论依据。

Conjugated linoleic acid (CLA) refers a group of positional and geometric isomers of linoleic acid with conjugated double bond. CLA can be produced by chemical methods, however the products are complex and often mixed with CLA isomers. Lactic acid bacteria (LAB) can produce c9,t11-CLA which have immunity modulation activity. Therefore, biological methods for CLA production has attracted much attention. Bifidobacteria is the most yield of single CLA isomer, unfortunately, its mechanism and regulation for CLA production remains unclear. In this proposal, with a high CLA production strain of Bifidobacterium breve, combined with genomics, metabolomics and transcriptomics and molecular biology methods, we will focus on the functional genes composition, activity and transcription as well as metabolite accumulation to explain the the molecular mechanism and regulation mechanism for CLA production. Information obtained would be helpful for industrial production of CLA, and beneficial evaluation and application of B. breve.