Microbial Production of Bioplastics: An Eco-friendly Alternative

Abstract

Accumulation of non-biodegradable plastic has shown adverse impacts on the environment and calls for a dire need for a sustainable alternative. Various microbial strains can produce bioplastics in the form of Polyhydroxyalkanoates (PHAs) as energy reserves. Many bacteria, fungi and microalgae have been studied to produce such biopolymers. PHAs are biodegradable and meet the basic requirements of life cycle environmental impact or life cycle assessments for proper disposal. They are also biocompatible and renewable. They have high Elastic modulus, Tensile modulus, melting temperature, and crystallinity with many other properties similar to synthetic plastics currently in use, making them a more reliable and sustainable substitute. Bioplastics produced from PHAs have found a myriad of applications in medicine, pharmaceuticals, agriculture and the packaging industry. This review emphasizes the structure of PHAs, their biosynthesis and relevant microbial strains employed, including genetically engineered strains, microbes from extreme niches and mixed microbial cultures. It focuses on using cheap and sustainable carbon feedstocks, including agricultural residues, lignocellulosic biomass and crude glycerol, on making the production of PHAs cleaner and commercially feasible. Industrially scaled production using different fermentation strategies, downstream processing and purification, along with the wide range of applications of PHAs, is also discussed.