许多细菌能合成聚羟基脂肪酸酯（PHA）作为储存碳源和能量的物质。由于其可加工性、生物相容性和生物可降解性，PHA被认为是一种绿色塑料而引起了世界各国科学界和产业界的重视。微生物合成的PHA的单体种类多样、彼此之间结构差别很大，这就使不同PHA的热力学性质有很大的不同。近来我们的研究表明，通过对假单胞菌的β-氧化循环中的一些基因的调控，可以部分实现对PHA中单体和结构进行一定的控制，获得所需的PHA。本项目拟基于上述研究成果，对已知的微生物PHA合成路径进行分析，找出互相影响和调控的机制，删除影响PHA合成的路径，从而建立基于恶臭假单胞菌的PHA的合成平台，能够设计和获得具有所需结构的PHA。并提出PHA合成和结构调控的新机制。

Polyhydroxyalkanoates (PHA), a family of diverse biopolyester, can be accumulated by a wide range of bacteria as carbon and energy storage compounds. It is considered as a new type of promising bioplastic because of its good thermal-mechanical properties combined with biocompatibility and biogradability. PHAs have flexible thermal and mechanical properties depending on their monomer structures and monomer ratios. Our recent studies showed that manipulation on genes involved in β-oxidation including deletion of fad regulons, resulted in partially controllable PHA structures. In this study, Pseudomonas putida will be used as a platform for investigating the mechanism of the formation of diverse PHAs. Based on known PHA synthesis pathways, by finding out genes that are related to PHA synthesis and structure regulation, and by deleting pathways that influencing PHA structures, a new regulation mechanism on how the bacterium regulates PHA synthesis using simplified PHA synthesis pathways can be established, which will allow us to achieve rational design of PHA structures.