Abstract Polyhydroxyalkanoates (PHA) produced by many bacteria have been
investigated by microbiologists, molecular biologists, biochemists, chemical
engineers, chemists, polymer experts, and medical researchers over the past many
years. Applications of PHA as bioplastics, fine chemicals, implant biomaterials,
medicines, and biofuels have been developed. Companies have been established or
involved in PHA-related R&D as well as large-scale production. PHA synthesis has
been found to improve the robustness of non-PHA-producing microorganisms and
to regulate bacterial metabolism, leading to yield improvement for some bacterial
fermentation products. In addition, amphiphilic proteins related to PHA synthesis
including PhaP, PhaZ, and PhaC have been found to be useful for achieving protein