Non-petroleum based biological polyester will be one of the most important next-generation polymers in the future years due to limited nature resource.  The formation of polyesters by microorganisms has more attention, especially for potential application as bioplastics.  One of these polyesters is called poly-hydroxyalkanoates (PHAs), which are a whole family of different polyesters. Among the various biodegradable polymer materials, PHAs provides a good fully degradable alternative to petrochemical plastics. The properties of PHAs are very similar to those of polyethylene (PE) and polypropylene (PP). The copolymers of the Poly-3-hydroxybutyrate (PHB) and polyhydroxyvalerate (PHV) are far less permeable to oxygen than polyethylene and polypropylene. This character makes PHAs copolymers to be a better material for food packaging because there is a reduced need for antioxidant addition.  This review paper covers the basic studies of microbial systems, production processes, and applications of PHAs.  Three subtopics are included: (i) microorganisms and their modification for production of PHAs, (ii) fermentation and separation processes of PHAs, and (iii) polymer modification and characterization for product applications of PHAs, which works include the screening, genetics, biophysics, and biochemical analysis of targeted microorganisms.