Microbial polyhydroxyalkanoates (PHAs) are biopolyesters produced by microorganisms as intracellular granules under nutrient stress. Due to non-toxic and biodegradable behavior these polyesters are a sustainable source of wide range of biomaterials such as bioplastics. As a result of excellent polymeric properties such as melting temperatures (T_m), glass transition temperature (T_g), crystallinity, Young’s modulus and stress to break ratio these polyesters are capable of replacing the synthetic plastics. Bioplastics produced using PHAs as biomass source can be used for packaging material and disposable products on the other hand biofuels can also be generated using PHAs. PHAs find countless applications in industry, agriculture, pharmaceuticals and health. A large number of bacterial, microalgal and fungal species can produce these polyesters. Bacterial species such as Bacillus megaterium, Pseudomonas aeruginosa, P. oleovorans, P. stutzeri and Cupriavidus necator are some highly studied microorganisms for PHA production. This review summarizes the most important aspects of PHAs, crystalline and granular structure of PHA biosynthesizing genes and their relevant proteins. Thermal and physical properties, sources, extraction, purification methods of PHAs are briefly discussed. Applications of PHAs, phylogenetic analysis of Pseudomonas sp. in term of its PHAs synthesizing genes, future prospects and possible outcomes are discussed.

微生物聚羟基链烷酸酯（PHA）是微生物在营养胁迫下以细胞内颗粒形式产生的生物聚酯。由于无毒和可生物降解的特性，这些聚酯是各种生物材料（如生物塑料）的可持续来源。由于具有出色的聚合性能，例如熔融温度（T _m），玻璃化转变温度（T _g），结晶度，杨氏模量和应力断裂率这些聚酯能够代替合成塑料。使用PHA作为生物质源生产的生物塑料可用于包装材料，而一次性产品也可使用PHA生产生物燃料。PHA在工业，农业，制药和健康领域有无数的应用。大量细菌，微藻和真菌物种都可以生产这些聚酯。细菌物种例如巨大芽孢杆菌，铜绿假单胞菌，P.食油假单胞菌，施氏假单胞菌和钩虫贪铜菌是一些生产PHA的经过高度研究的微生物。这篇综述总结了PHA，PHA生物合成基因及其相关蛋白的晶体和颗粒结构的最重要方面。简要讨论了PHA的热和物理性质，来源，提取，纯化方法。PHAs的应用，假单胞菌属的系统发育分析。就其PHA合成基因而言，讨论了其未来前景和可能的结果。