PHB (poly--hydroxybutyrate) and its enzymatic degradation

Our daily life needs depend on plastics, as they are cheap and durable, so they become the most commonly used synthetic chemical products. But from an environmentalist's point of view, a major concern related to these plastics is their non-biodegradable nature. Driven by growing demand to search for sustainable solutions to dispose off generating huge volume of synthetic plastic wastes, shifted the mind of researcher towards the use of biodegradable plastics which can be completely disposed-off by microbial enzymatic degradation. These biodegradable plastics or bioplastics are also synthesized by microbes under certain stressed environmental conditions out of which poly(R-3-hydroxybutyrate) (PHB) is the most ubiquitous and best known representatives of polyhydroxyalkanoate family. The PHB is most intensively used for the innovative biomedical applications owing to suitable combination of biocompatibility, transport characteristics, and mechanical properties. These challenging aspects of PHB can be used for designing of novel medical devices, in tissue engineering, and for systematic sustained drug delivery. Lots of research reports on PHB degrading enzymes and their producing microorganisms including biochemical aspects are available but in scattered form. So this review highlighted all the relevant information of PHB and PHB-degrading enzymes starting with basic classification, synthesis, mechanism, and applications that are environment friendly and are of public interest.