Oprimization of production system for bioplastics by enzyme evolutionary engineering

通过开发各种代谢工程策略，包括基于外部底物操作的天然存在的PHA生产细菌的发酵技术（第一代），随后用重组基因技术（第二代）加强，用于生物合成聚羟基链烷酸酯（PHA）生物聚酯的生物技术研究已得到广泛进展。最近，“酶进化”正在成为PHA生产的第三代方法。以齐格勒-纳塔系列催化剂为代表的“催化剂进化”是化学合成高分子的突破性进展。因此，人们可以很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。2001年本课题组首次报道了PHA生物合成中的体外酶进化试验。本研究项目是在短时间内逐步积累的文献资料和实验结果的基础上，将“酶进化”应用于PHA生物合成的概念和目前的案例研究作为研究重点。

Biotechnological studies for biosynthesis of polyhydroxyalkanoates (PHAs) biopolyester have been extensively progressed through the development of various metabolic engineering strategies involving fermentation technology of naturally occurring PHA-producing bacteria based on external substrate manipulation (1st generation), subsequently reinforced with recombinant gene technology (2nd generation). Most recently, "enzyme evolution" is becoming the 3rd generation approach for PHA production. Break-through in chemical synthesis of macromolecules with desirable properties was achieved by development of prominent chemical catalysts, "catalyst evolution", as represented by a series of Zigler-Natta catalysts. Thus, one can easily accept the concept that molecular evolution of the biocatalysts (enzymes) relevant to PHA synthesis will provide us a chance to create novel PHA materials with high-performance. The first trial of the in vitro enzyme evolution in PHA biosynthesis was reported by our group in 2001. The following literature data as well as our own experimental results devoted to this new approach have been gradually accumulated for a short time.This research project focused specifically on the concept and current case studies of the application of "enzyme evolution" to PHA biosynthesis.