利用合成生物技术高效合成大肠杆菌新型scl-mcl PHA的基础研究

利用合成生物技术和生物系统工程策略对生物体进行理性改造，以解决生物医药、能源及生物材料等领域的重大问题是目前亟需突破的关键之一。聚羟基脂肪酸酯(简称PHA)因具有多种优良性能而成为绿色聚合物生物合成中富有挑战性且备受关注的研究工作。本项目将合成生物学中的模块化、系统工程化设计思路引入大肠杆菌新型短链-中长链单体共聚PHA(scl-mcl PHA)的合成路径构建中。利用模块途径工程和空间模块化改造，将奇、偶数碳链单体的合成模块植入经优化构建的大肠杆菌“底盘”中，进行模块间及模块与底盘间高适配性的改造，旨在以廉价碳源葡萄糖为唯一底物，高效合成一系列奇、偶数碳链单体共聚的新型非天然生物基材料PHA。利用代谢产物分析检测，揭示人工生物系统中底盘和模块优化与PHA奇、偶数碳链单体合成之间的相关性，解析大肠杆菌高效合成PHA的关键节点，为实现适用于不同领域的scl-mclPHA的生物制造奠定基础。

One of the keypoints in need of breakthrough at present is reconstructing organism rationally by synthetic biological technologies and strategies of biosystems engineering to solve the major issues in the fields of biomedicine, biofuels and biomaterials. The superior performance of PHA copolymer made it the challenging research and attracted a lot of attention in green copolymer biosynthesis. This study introduces the thinking of modules and systems engineering design from synthetic biology into short-chain-length-co-medium-chain-length PHA (scl-mcl PHA) copolymer biosynthesis in Escherichia coli. We implant the modules of even- numbered monomers and odd-numbered monomers into the well-characterized E. coli chassis via modular pathway engineering and space modular transformation. By high intermodular compatibility and suitability among modules and chassis, new types of non-natural PHA copolymers as bio-based materials with even-numbered and odd- numbered monomers will be obtained efficiently from the single carbon source- glucose. It can be discovered that the correlation between modular optimization in the artificial biological system and even-numbered or odd-numbered monomer biosynthesis and the critical node of high production of PHA in E. coli by analysis and test of metabolic products. It also lays foundation for scl-mcl PHA bio-manufacturing suitable for different fields.