基于“线粒体” 微囊结构的分隔式多酶联级催化体系的定向设计及催化机理研究

There are structural defects including inflexible enzymatic isolated area and location in the existing spatially isolated multienzyme catalytic systems. To solve these problems, the project will firstly rationally design Metal organic frameworks (MOF) particles with select permeability and diversified enzyme-immobilization forms with horseradish peroxidase and glucose oxidase as model by thoroughly analyzing self-growth on a single enzyme surface, self-assembly on the oil-water interface and hierarchical self-growth on multienzyme surface of nano-sized zeolitic imidazolate framework (ZIF-8). Secondly, three spatially isolated multienzyme cascade catalytic systems based on mitochondrion-like microcapsule structures, wall-lumen multienzyme cascade catalytic system, quasi-lumen multienzyme cascade catalytic system and wall multienzyme cascade catalytic system, will be explored by optimizing the encapsulation of horseradish peroxidase in Pickering emulsion stabilized by the single enzyme-support MOF particles or formation of Pickering hollow microcapsules stabilized by multienzyme-support MOF particles. Thirdly, the project will clarify the catalytic mechanism of the spatially isolated multienzyme catalytic system and the regulatory mechanism of its structure on catalysis process on the basis of the change law of enzyme distribution location and regional space, catalytic medium in the spatially isolated multienzyme catalytic system and the influence of its structure on catalytic process. The research work will provided a new direction to achieve a more efficient nano-enzyme catalyst and make a contribution to the energy-saving product in a green and efficient way.

针对现有分隔式多酶催化体系多酶的分隔方式和结构单一等缺陷，本项目以辣根过氧化物酶与葡萄糖氧化酶为模型，深入分析纳米级金属有机骨架（MOF）材料沸石咪唑酯骨架ZIF-8的前驱体在单酶表面自生长过程、在油水界面的自趋向规律及在双酶表面的分层自生长过程，进而理性设计出具有选择通透性和多样化载酶特性的MOF材料颗粒；同时，探索并优化负载单酶的MOF颗粒稳定的皮克林乳液包覆辣根过氧化物酶形成中空微囊的制备过程以及负载双酶的MOF颗粒稳定的皮克林中空微囊的形成过程，构建出三种具有“线粒体”微囊结构的分隔式囊壁-囊腔、类囊腔或囊壁双酶催化体系；深入剖析酶分布形式和区域空间、催化介质及微囊结构对催化过程的影响规律等，揭示分隔式多酶催化体系的催化机理及结构特性对酶催化过程的调控机制。该研究为高效纳米多酶催化剂的制备提供了一个新方向，为实现产品节能减排提供了一条绿色、高效的途径。

高效联级催化反应的构建需要良好的底物传输通道作为基础，其核心为使底物在高速传输的介质上建立适距的催化活性位点，并形成局部空间的浓度梯度。但是目前已知的分隔式多酶催化体系，其多酶的分隔方式单一，制备工艺无法实现多酶分布位置、酶分子区域空间和催化介质的差异化。本项目以辣根过氧化物酶与葡萄糖氧化酶为模型，深入分析纳米级金属有机骨架（MOF）材料沸石咪唑酯骨架ZIF-8的前驱体在酶表面自生长过程、在油水界面的自趋向规律及在双酶表面的分层自生长过程，进而理性设计出具有选择通透性和多样化载酶特性的MOF材料颗粒。包括通过仿生矿化作用合成一种脂肪酶-ZIF-8复合多孔纳米材料；通过MOF仿生矿化作用与多巴胺生物粘性相结合，合成了一种可定位组装葡萄糖氧化酶与脂肪酶双酶位置的复合纳米材料PDA@ZIF-8；通过核壳ZIF-8@ZIF-8纳米结构中构建多酶生物催化剂；通过预合成的ZIF-8纳米粒子在油水界面的自组装，并在胶囊外沉积一层致密的ZIF-8壳层来制备MOF基微胶囊；利用山梨醇单油酸酯(Span-80)，开发了一种基于分子筛咪唑骨架-8(ZIF-8)的胶体中实现辣根过氧化物酶/葡萄糖氧化酶双酶体系；基于中空ZIF-8胶体囊（H-ZIF-8）合成了一种分隔式葡萄糖传感器。该项目为高效纳米多酶催化剂的制备提供了新方向，为实现产品节能减排提供了一条绿色、高效的途径。