Recent advances of sustainable Short-chain length polyhydroxyalkanoates (Scl-PHAs) - Plant biomass composites

Plastic pollution has become a global threat to humanity. Fortunately, humanity has always found ways of overcoming such threats through multipronged approaches. To overcome this current threat brought about by anthropogenic linear pattern of take-make-use-dispose of fossil-based plastics, an intentional approach of adopting biobased plastics which are renewable has taken shape. In this approach, governments, industry, and academia are at the forefront of making determined commitments to slow down the spiralling carbon footprint and aim at net zero carbon emissions by 2050. In this regard, PHAs which have a rich resume of desired properties to replace non-renewable fossil-based plastics are increasingly becoming popular. However, PHA production cost is still high compared with the fossil-based plastics and there exists properties performance gap because they are typically brittle, especially the short chain length PHAs (Scl-PHAs). Considerable efforts are geared towards tuning the mechanical properties as well as reducing the cost to meet the market requirements. The most authentic way of tackling these twin-challenges of reducing the cost of PHA products and their properties enhancement is the incorporation of fillers sourced from renewable sources, especially the plant biomass. In this comprehensive review, Scl-PHAs biopolymers are discussed, their modifications with plant biomass (natural fibres and components, agro-residues, and industrial residues) are elucidated. Moreover, their wide scope of applications, sustainability performance (biodegradation studies) and other viable end-of-life options are amply discussed. Finally, we draw conclusions and highlight future opportunities in this exciting bioplastic area.

Automated summary

Plastic pollution is a global threat, and the adoption of biobased plastics as a replacement for fossil-based plastics is gaining attention. However, the high production cost and properties performance gap of biobased plastics need to be addressed. The incorporation of renewable fillers seems to be the most promising solution.