代谢综合征困扰着全球约25%的人口，已成为当今最严峻的公众健康问题之一。研究表明海藻多糖可以通过调节肠道菌群而缓解代谢紊乱，而它自身又可以被肠道菌多糖裂解酶代谢。但是其调节肠道菌群的机制，肠道菌组成的改变如何影响代谢综合征，是否存在特定种类或组成的海藻多糖更容易被多糖裂解酶代谢或有更好的治疗代谢紊乱的效果等问题仍不明确。本项目拟通过宏基因组技术揭示健康小鼠与代谢综合征小鼠肠道菌中核心多糖裂解酶的不同，对关键的多糖裂解酶进行异源表达及其代谢海藻多糖的特点进行研究；通过小鼠实验考察经多糖裂解酶水解前后的海藻多糖治疗代谢综合征的效果，及其对肠道菌群和多糖裂解酶的影响，确定疗效最佳的海藻多糖并阐述多糖裂解酶在海藻多糖治疗代谢综合征中的作用机制。本项目将为以多糖裂解酶为靶点的特殊医疗食品、保健品和药品开发奠定理论研究基础，为海藻多糖产品开发提供科学依据，本研究具有创新性、前瞻性和潜在的商业应用价值。

Metabolic syndrome plagued about 25% of the world's population and has become one of the most serious public health problems of today. Studies have shown that seaweed polysaccharides could alleviate metabolic syndrome by regulating gut microbiota structure, and could also be metabolized by gut microbial polysaccharide lyases. However, the mechanism of these polysaccharides modulates the gut microbiota structure, how the gut microbiota modulation contributes to metabolic syndrome, and whether exists a specific species or composition of seaweed polysaccharide which is more susceptible to be degraded by polysaccharide lyase or exhibits better anti-metabolic syndrome effect have not been confirmed. This project aims to reveal the difference of core polysaccharide lyases in the gut microbiota of healthy and metabolic syndrome mice through metagenomic data-mining. Then, the heterologous expression of the key polysaccharide lyases and their enzymatic properties in cleaving seaweed polysaccharides were investigated. Moreover, the effects of selectively hydrolyzed and the parent seaweed polysaccharides on alleviating metabolic syndrome and regulating the composition of gut microbiota as well as polysaccharide lyases were investigated in mice. Finally, seaweed polysaccharides showing best anti-metabolic syndrome effect would be identified, and the mechanism of polysaccharide lyases in the treatment of metabolic syndrome by seaweed polysaccharides was explored. This project lays a theoretical foundation for the development of polysaccharide lyase targeted special medical foods, health products, and pharmaceuticals, and provide a scientific basis for the development of seaweed polysaccharide products. This project is innovative, forward-looking and has potential commercial application value.