Microbial Biopolymers and Enzymes Involved in the Biosynthesis of PHAs

Abstract

AbstractBiopolymers are natural alternatives for synthetic polymers which can be obtained from natural sources and represent themselves as sustainable solution for nondegradable plastic. Biopolymers are plastic-like substances obtained from organic sources that have applications in the development of reliable, nontoxic, but degradable packaging materials. Organic sources of hydrocolloids, polysaccharides, lipids, and protein have been used to extract biopolymers. However, recently microbial production of biopolymers has received much attention. Polyhydroxyalkanoates (PHAs) are intracellular granules produced by certain microorganisms under nutrient stress. Several bacterial species (Cupriavidus necator, Pseudomonas stutzeri, P. oleovorans, P. aeruginosa, and Bacillus megaterium) and many fungal and algal species are known for PHA production. Structural and regulatory genes for PHA synthesis are present in an operon in producing microorganisms with slight differences. PHAs have many applications in various industrial sectors such as food, agriculture, and pharmaceuticals. PHA can be exploited in several ways like biofuel generation as well as can be used in packaging material.This chapter provides a comprehensive information of biopolymers and their composites, microbial biopolymers, and main biosynthetic pathways used for PHA production. Important aspects of PHAs, its biosynthesizing genes, and their relevant proteins have also been summarized.KeywordsBioplasticBiopolymersFood packagingPolyhydroxyalkanoatePHA synthase