Polyhydroxyalkanoates (PHA) are diverse polyesters synthesized by a variety of bacteria as intracellular carbon and energy storage compounds. As bio-renewable and biodegradable materials with diverse properties, PHA have drawn industrial attentions for their potential applications in many fields. This review focuses on recent strain developments for PHA production via cofactor engineering and metabolic engineering. The microaerobic production of PHA and application of PHA synthesis genes for improving robustness of industrial microorganisms are addressed.