Advances and trends in microbial production of polyhydroxyalkanoates and their building blocks

Abstract

With the rapid development of synthetic biology, a variety of biopolymers can be obtained by recombinant microorganisms. Polyhydroxyalkanoates (PHA) is one of the most popular one with promising material properties, such as biodegradability and biocompatibility against the petrol-based plastics. This study reviews the recent studies focusing on the microbial synthesis of PHA, including chassis engineering, pathways engineering for various substrates utilization and PHA monomer synthesis, and PHA synthase modification. In particular, advances in metabolic engineering of dominant workhorses, for example Halomonas, Ralstonia eutropha, Escherichia coli and Pseudomonas, with outstanding PHA accumulation capability, were summarized and discussed, providing a full landscape of diverse PHA biosynthesis. Meanwhile, we also introduced the recent efforts focusing on structural analysis and mutagenesis of PHA synthase, which significantly determines the polymerization activity of varied monomer structures and PHA molecular weight. Besides, perspectives and solutions were thus proposed for achieving scale-up PHA of low cost with customized material property in the coming future.

Bioplastic degradation by a polyhydroxybutyrate depolymerase from a thermophilic soil bacterium

“…PHA depolymerases are a key element of PHA circularity. To date, the development of PHA as a replacement for petroleum based polymers like polyethylene and propylene has focused on the biofermentation of the polymer, and includes strain selection, feedstock choice, bioreactor parameters, and metabolic/pathway engineering to improve yields (for a review see 28 ). Now that production methodology has been established by several global companies, studies have shifted to how the polymer can be processed by industrial methods designed for processing polyethylene and polypropylene.…”

Identification of a Novel Aerobic Promoter for efficient poly(3-hydroxybutyrate) Synthesis in Recombinant Escherichia coli

“…E. coli is extensively utilized as a host for metabolic engineering the recombinant expression of heterogonous genes, including commonly employed reporter genes (green uorescent protein, GFP) or other genes of interest. Poly(3-hydroxybutyrate) (P3HB) has emerged as a promising candidate among completely biodegradable polymers, owing to its mechanical properties similar to those of petroleumderived polymers and its capacity for complete biodegradation (Gao et al 2022). the synthesis of P3HB is an aerobically process; however, it encounters an oxygen-limited environment during the fermentation process (Wei et al 2015).…”

Characterization of polyhydroxyalkanoate‐based composites derived from waste cooking oil and agricultural surplus

“…[2,3] PHAs are microbial polyesters with thermoplastic properties similar to conventional plastics that can be synthesized by a wide range of microorganisms under nutrient stress conditions. [4][5][6] Using waste materials in PHA production can help to reduce PHA production costs, which is an important step toward achieving more competitive production costs against conventional plastics. Some notable examples include the use of waste plant oils, molasses from the sugar industry, lignocellulosic materials, oil palm shells, pressed fruit fiber, biodiesel waste, and waste animal oil.…”