Autotrophic bacterial production of polyhydroxyalkanoates using carbon dioxide as a sustainable carbon source

The persistence of fossil fuel-based plastics poses significant environmental challenges, prompting increased research into biodegradable polyhydroxyalkanoate (PHA) polymers derived from cost-effective and sustainable resources. Different microorganisms can produce PHA amongst carbon dioxide (CO₂)-assimilating autotrophic organisms, particularly noteworthy in carbon capture and utilization (CCU). Autotrophic bacteria have evolved to utilize either light (photoautotrophy) or inorganic chemicals (chemolithoautotrophy) to capture CO₂, which powers their primary and secondary metabolic activities. This review explores the diversity of PHA-producing autotrophs, the metabolic pathways implicated in autotrophic PHA accumulation, and recent progress in photoautotrophs and chemolithoautotrophs regarding PHA synthesis using CO₂. Additionally, microbial electrosynthesis for converting CO₂ to PHA is also discussed. Genetic engineering strategies are also emphasized for the autotrophic synthesis of PHA. This review also addresses the challenges and prospects for sustainable PHA production using CO₂.