A review on polyhydroxyalkanoate (PHA) production through the use of lignocellulosic biomass

Polyhydroxyalkanoates (PHAs) are aliphatic polyesters produced via bacterial fermentation of sugars and fatty acids and are considered to be a promising material to aid in mitigating plastic pollution due to their universal biodegradability. With an expected 12 billion metric tons of plastic to accumulate within landfills and ecosystems by 2050, this mitigation is desperately needed. The major bottleneck in the commercial feasibility of PHAs is the high cost compared to their non-biodegradable synthetic counterparts currently predominant throughout the packaging and single-use goods industry, with PHAs costing 3–12× more than traditional plastics. With approximately 50% of the production costs attributed to the fermentation substrate, a significant opportunity exists to dramatically cut the cost of PHA production through the use of a low or no-cost substrate. These biodegradable polymers can be sustainably produced from a variety of waste materials. Lignocellulosic biomass is the most abundant natural material on earth and can potentially be used for this purpose. This review includes an overview of the PHA production process such as metabolic pathways, reactor configurations, and pre-treatments for lignocellulosic biomass. The results from various studies using lignocellulosic biomass for PHA production were compared. Finally, potential drawbacks and opportunities are discussed for the viability of integrating the sustainable production of PHAs into the global circular economy. This work satisfies the UN's sustainability goal of responsible consumption and production (Sustainable Development Goal 12).