Medical grade biodegradable polymers: A perspective from gram-positive bacteria

Globally, increased dependence on fossil fuels for manufacturing plastics, scarcity of space for disposal, and ongoing environmental concerns for nonbiodegradable chemical-based plastics have fueled research toward sustainable process development of cost-effective, eco-friendly, and biodegradable polymers. In this context, polyhydroxyalkanoates (PHA) have drawn much attention as a good candidate and are classified as both biodegradable and biocompatible polyesters which closely resemble conventional plastics. At present, though the technology for PHA and its copolymer production is on an industrial scale, its usage and distribution in varied industrial sectors are still limited due to the relatively high production cost. A high cost is incurred due to the use of expensive, chemically synthesized carbon sources (~ 40% of the total cost), which thereby make it difficult to compete with petroleum-based polymers. In this respect, efforts are being made to reduce cost and make it an environmentally benign process by the development of better bacterial strains, an efficient fermentation and recovery strategy, use of low cost, renewable resources (as carbon source) such as cheese whey, starch, cane molasses, industrial waste glycerol, wastewater, oil, and fats. In the past few years, renewable resources have attracted much interest in producing value-added products. In this review, the current developments in biodegradable polymers in term of their production process through the biotechnological route mainly by Gram-positive bacteria using renewable resources and the applications of widely studied PHA, i.e., poly-3-hydroxybutyrate in different industrial sectors with emphasis on the biomedical sector, will be explored.