Prroduction System for Carbon Recyclable Green Plastics Based on Enzyme Evolutionary Engineering

聚羟基脂肪酸酯（PHA）形成一类天然聚酯，环境中的许多微生物以细胞内颗粒的形式积累以储存碳和还原当量。各种各样的单体产生具有取决于聚合物组成的不同材料性质的PHA。除了PHAs作为生物塑料的实际应用外，从学术代谢途径工程师的角度来看，PHAs是可生物降解的，由可再生资源制成。PHA是代谢工程的模型化合物。PHA代谢工程的主要目的包括控制决定聚合物材料性质的不同因素，如单体组成、分子量和共聚物微观结构，以及优化产率。PHA生产的途径工程提供了在低成本、高生产率发酵中合成具有所需性质的新型聚合物的机会。最近，酶的进化正在成为新的 ...更多信息 生产PHA的方法。通过“催化剂进化”，开发出性能优异的化学催化剂，实现了高分子化学合成的突破。因此，人们可以容易地接受这样的概念，即与PHA合成相关的生物催化剂（酶）的分子进化将为我们提供创造具有高性能的新型PHA材料的机会。酶进化辅助PHA生产系统参与碳生态系统。在这项研究中，我展示了酶工程优化生产力和PHA单体组成的调节的案例研究。基于PhaJ的三维结构对单体供应酶进行了合理的分子设计，基于功能定位对PHA合成酶进行了进化工程。通过对PHA生物合成的关键酶进行工程改造，产生了大量的酶突变体库，可以提供适合广泛应用的具有不同特性的定制生物聚合物。已将突变体转移到植物系统中。少

Polyhydroxyalakanoates (PHAs) form a class of natural polyesters that many microorganisms in the environment accumulate in the form of intracellular granules to store carbon and reducing equivalents. The wide variety of monomers yields PHAs with diverse material properties that depend on polymer composition. Besides the practical applications of PHAs as bioplastics that are biodegradable and made from renewable resources, from the standpoint of an academic metabolic pathway engineer. PHAs are model compounds for metabolic engineering. The primary aims of the metabolic engineering of PHAs include controlling different factors that determine polymer material properties, such as monomeric compositions, molecular weight and copolymer microstructure, as well as optimizing yield. Pathway engineering for PHA production offers the opportunity to synthesize novel polymers with desirable properties in low-cost, high-productivity fermentations. Most recently, enzyme evolution is becoming the new … More approach for PHA production. A break-through in the chemical synthesis of macromolecules with desirable properties was achieved by the development of prominent chemical catalysts via "catalyst evolution". Thus, one can easily accept the concept that the molecular evolution of the biocatalysts (enzymes) relevant to PHA synthesis will provide us with a chance to create novel PHA materials with high performance. The enzyme evolution-aided PHA production system be involved in the carbon ecosystem. In this study, I demonstrated the case studies of enzyme engineering for optimization of productivity and regulation of monomeric composition of PHA. Rational molecular design was applied to monomer supplying enzyme based on three dimensional structure of PhaJ and evolutionary engineering was applied to PHA synthase based on functional mapping. A huge amount of library of enzyme mutants, created through engineering of these key enzymes for PHA biosynthesis, can provide tailor-made biopolymers with diverse properties suitable for wide-range applications. Transferring mutants to the plant system has been performed. Less