Chapter 5 - Processes and characterization for biobased polymers from polyhydroxyalkanoates

Abstract

The present trend of fabricating nondegradable conventional plastics, that is, petroleum-based plastics from ever-diminishing and environmentally unfriendly fossil fuel sources is unsustainable. Therefore, substituting petroleum-based plastics with biodegradable plastics like polyhydroxyalkanoates (PHAs) can potentially diminish the release of greenhouse gas and fossil energy exploitation by 200% and 95%, respectively. Interestingly, PHAs are exclusively fabricated within the cytoplasm of microbes like bacteria and cyanobacteria as a polymeric storage compound for carbon and energy. Globally, owing to promising applications analogous to petroleum-based plastics, microbial PHAs have received considerable interest in biodegradable polymer market for various commercial ventures in the field of packaging, agriculture, biomedicals, etc. Among such ventures, the packaging field (with the food segment) is the key revenue-generating segment due to the increasing interest of biodegradable packaging material. For instance, biopolymeric poly-3-hydroxybutyrate (PHB) is developed from sugarcane bagasse by Brazilian PHB Industrial S/A for promising uses such as cosmetic packaging, auto parts, and toys. Currently, although the technological production of PHAs is on an industrial scale, its uses, as well as circulation in diverse commercial segments including packaging field, are still restricted owing to poor cost-efficacy, where approximately 50% of the total production cost is because of pure carbon source feedstock. As a result, this limitation makes PHAs difficult to compete with conventional plastics. Thus, successful commercialization of PHA bioplastics in various sectors including the packaging field requires a reduction in overall PHA production cost through advanced technological strategies such as exploitation of cost-effective renewable carbon sources, improvement in PHA productivity, and advances in PHA recovery technique. Overall, this chapter provides a current insight into the recent trends, barriers, and solutions of microbially originated PHAs as eco-friendly food packaging material.