双歧杆菌生物转化共轭亚油酸（CLA）的调控机制和作用规律

作为一种功能脂质，具有生物活性的共轭亚油酸（CLA）异构体受到极大关注。双歧杆菌是目前生物转化CLA能力最强的种属，并且作为益生菌对宿主营养代谢和免疫调节均有促进作用，是最为理想的生物转化CLA的潜在微生物资源。然而目前关于双歧杆菌生物转化CLA的分子机理和调控机制研究还十分有限。申请人近期通过对一株高产CLA的短双歧杆菌进行研究，首次挖掘出了双歧杆菌生物转化CLA的关键酶-亚油酸异构酶（命名为BBI）。对BBI在双歧杆菌中的分布情况进行初探后发现，此基因在双歧杆菌中普遍存在，但双歧杆菌生物转化CLA的能力却在种和株水平上存在很大差异。本项目拟在前期研究基础上，从不同种双歧杆菌生物转化CLA的关键酶基因、转录调控蛋白和特征代谢物三者的分布情况和互作关系入手，全面阐明双歧杆菌生物转化CLA的调控机制和作用规律，最终为高产CLA双歧杆菌的工业化应用提供理论依据和技术支持。

The functional lipid conjugated linoleic acid (CLA) has drawn much attention for its health-promoting effects. Bifidobacteria are regarded as the most promising microbial resource in CLA bioconversion due to the highest capability, and they have been identified to be beneficial to human immunoregulation and nutrition metabolism. However, the research on molecular and regulatory mechanism of CLA bioconversion is still limited. Previous studies have identified a key enzyme (called Bifidobacterium breve isomerase, BBI) involved in CLA bioconversion pathway in a Bifidobacterium breve strain. Preliminary assay reveals that BBI is extensively distributed in the bifidobacteria, while bifidobacterial CLA bioconversion capability demonstrates remarkable difference among species and strains. This project will identify the key enzymes in CLA bioconversion, the transcription-regulation protein and the characteristic metabolites, and clarify the interrelationship among them. Combining with molecular method, this project will further identify the precise regulating pathway and also elucidate the detailed function rule of bifidobacterial CLA production, which could provide solid foundation for application in the future.