An inclusion body located in the cytoplasm that consists of polyhydroxyalkanoate (PHA) molecules and associated proteins, surrounded by a phospholipid monolayer; the proteins include PHA synthase, PHA depolymerase and 3HB-oligomer hydroxylase, phasins (PhaPs), which are thought to be the major structural proteins of the membrane surrounding the inclusion, and the regulator of phasin expression PhaR.