【作者】 孙倩芸；

【导师】 姜忠义；

【作者基本信息】 天津大学 ， 化学工艺， 2009， 硕士

【摘要】 自然合成了大量结构复杂性能优越的有机、无机或有机/无机杂化材料,这些材料与常规材料相比有着特殊的性质,从而实现了生物体各种优异的功能。仿生矿化可实现温和条件下(常温、中性pH)无机氧化物的形成,并可通过生物模板或合成模板的自组装来调控无机氧化物的形貌,为酶固定化提供了新的思路。层层自组装过程可在常温水溶液中进行,条件温和,能维持酶分子的天然构象和生物活性,为固定化酶提供适宜的微环境。本论文以仿生硅化和自组装为主要方法,根据单酶及多酶体系对载体材料的要求进行固定化酶载体设计与制备,主要内容总结如下:首先,将仿生硅化与LbL层层自组装相结合,制备出鱼精蛋白/氧化硅杂化微囊用于醇脱氢酶(YADH)的单酶固定化。以CaCO3微粒为模板,在其表面交替组装有机的精蛋白层和无机的氧化硅层,然后用EDTA溶液去除模板得到鱼精蛋白/氧化硅杂化微囊,并阐明了微囊的形成过程和机理。将微囊用于固定化醇脱氢酶YADH的研究,发现微囊可为酶提供适宜的微环境,使酶保持较高的pH和热稳定性,以及较高的储存和重复使用稳定性。在上述工作的基础上,模仿细胞的结构,提出多酶微工厂的概念,将制备的鱼精蛋白/氧化硅杂化微囊包埋于海藻酸钙-鱼精蛋白-氧化硅(Alg-Pro-Si)微囊中,制备出具有Capsules-in-Capsule结构的多酶固定化载体。将鱼精蛋白/氧化硅杂化微囊包埋到Alg-Pro-Si微囊中,以Alg-Pro-Si微囊作为厂房, LbL微囊作为工作车间,含不同酶种的LbL微囊组成“酶催化装配线”,对输入的底物分子进行高效“加工”。Capsules-in-Capsule微工厂避免了不同种类酶分子间相互作用对酶活的影响;实现了多酶体系内部的功能分割,便于单独调节每种酶的催化特性。此外,LbL微囊包埋于较大Alg-Pro-Si微囊中,模仿细胞器间的分工协作,从大概念上又实现了多酶的共固定化,既缩短底物的传质路径,又有利于固定化酶与产物的分离制备的Capsules-in-Capsule微工厂在二氧化碳的酶法转化中表现了较高的甲醇产量,具有较高的储存和循环使用稳定性。更多还原

【Abstract】 The astonishing ability of living organisms to produce biocomposites with superior characteristics attracts the growing attention of numerous research groups. Biomimetic mineralization, which utilizes biological molecules or synthetic analogues to template and catalyzes the formation of inorganic oxides under mild conditions, provides a versatile new technology for enzyme immobilization with several inherent advantages. The morphology of the inorganic materials can be controlled by the template self-assembly. The process of LbL self-assembly is conducted in aqueous solution under mild conditions, which can well preserve the enzymes native structures and activities. Both of the biomimetic mineralization and self-assembly process can create benign microenvironment for the immobilized enzyme. This study discusses biomimetic and self-assembly approach for the formation of silica-based materials and their potential application in the preparation of enzyme carriers.The details in this study were summarized as follows:Firstly, mimicking the nacre layer in mollusk shell, a novel approach combining biomimetic mineralization with layer-by-layer (LbL) self-assembly was proposed to prepare protamine–silica hybrid microcapsules. More specifically, these microcapsules were fabricated by alternative deposition of positively charged protamine layers and negatively charged silica layers on the surface of CaCO3 microparticles, followed by dissolution of the CaCO3 microparticles using EDTA. Moreover, these protamine-silica hybrid microcapsules were employed as the carrier for the immobilization of YADH. The encapsulated YADH displayed enhanced recycling and storage stability.Secondly,inspired by the structure of cell, a microfactory with capsules-in- capsule structure was prepared for multienzymes immobilization. The Alg-Pro-Si capsules were loaded with LbL self-assembly microcapsules where the Alg-Pro-Si capsules worked as structural shell and the LbL microcapsules worked as“workshop”. By encapsulating different enzyme-containing LbL microcapsules within Alg-Pro-Si capsules, an enzymatic‘assembly line’could be created to alter the incoming molecules or‘manufacture’the product. The reaction probabilities and efficiencies would be considerably enhanced owing to spatial confinement of the biochemical machinery. The enzymes encapsulated by Capsules-in-capsule micro reactor displayed higher methanol yield and stability than free enzymes system.更多还原