A Review of Polyhydroxybutyrate Production from Wastewater Sources

Among our day's most significant worldwide problems are the vast numbers of non-biodegradable petroleum plastics, their manufacture and disposal, and the growing volumes of wastewater from industry and municipalities. Potential replacements for non-biodegradable petroleum-based plastics include biodegradable plastics made from biopolymers like polyhydroxybutyrate (PHB), which microorganisms produce. The present state of wastewater-cultivated microorganisms used in PHB production is reviewed in this research, along with several wastewaters that may be used to produce PHB in pure or mixed cultures. Additionally, commercially viable PHB-producing strains and suggested selection criteria for selecting the best PHB microbe for process improvement are emphasized. To illustrate recent advancements in genetic engineering approaches, this study also discusses the metabolic pathways involved in microbial PHB synthesis. Alongside the discussion of metabolic pathways, a comparative analysis of the outputs from different PHB production methods is provided to highlight the variability in yield and efficiency. In addition, it explores alternative metabolic routes and by-products that are co-produced with PHB in biorefinery systems, as well as the key factors that influence its biosynthesis. The impact of various extraction techniques on PHB yield and quality is also examined, aiming to facilitate the commercial-scale production of biodegradable polymers. Furthermore, the study provides an overview of current industrial players in PHB production that are contributing to the reduction of plastic pollution and greenhouse gas emissions. Altogether, this work highlights significant research progress in the field of microbial biopolymers, with a particular emphasis on PHB.