Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is a Polyhydroxyalkanoates type A polymer is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. More. It is Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. More, nontoxic, biocompatible plastic produced naturally by bacteria and a good alternative for many non-biodegradable synthetic polymers. It is a thermoplastic linear aliphatic polyester.