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

聚羟基藻酸酯（PHAs）是一种天然聚酯，环境中的许多微生物以细胞内颗粒的形式积累，以储存碳和还原物。各种各样的单体产生的pha具有不同的材料性质，这取决于聚合物的组成。从学术代谢途径工程师的角度来看，pha作为生物塑料的实际应用是可生物降解的，由可再生资源制成。pha是代谢工程的模型化合物。pha代谢工程的主要目标包括控制决定聚合物材料性能的不同因素，如单体组成、分子量和共聚物微观结构，以及优化收率。PHA生产的途径工程提供了在低成本、高生产率的发酵中合成具有理想性能的新型聚合物的机会。最近，酶进化正在成为PHA生产的新途径。通过“催化剂进化”开发出杰出的化学催化剂，实现了具有理想性能的大分子化学合成的突破。因此，人们可以很容易地接受这样一个概念，即与PHA合成相关的生物催化剂（酶）的分子进化将为我们创造高性能的新型PHA材料提供机会。酶进化辅助PHA生产系统参与了碳生态系统。在这项研究中，我展示了酶工程的案例研究，以优化生产力和调节PHA的单体组成。基于PhaJ的三维结构对单体供应酶进行合理的分子设计，基于功能作图对PHA合酶进行进化工程设计。通过对PHA生物合成的关键酶进行工程改造，建立了大量的酶突变体库，可以提供具有不同性质的生物聚合物，适用于广泛的应用。将突变体转移到植物系统中已经完成。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