Biodegradable Plastic Production from Waste C1 Carbon Sources: Current Trends and Future Directions

Plastic pollution poses a growing environmental and health threat, prompting the search for sustainable alternatives. Polyhydroxyalkanoates (PHAs) are biodegradable bioplastics synthesized by various microorganisms as intracellular reserves of carbon and energy. Among the most promising strategies for sustainable PHA production is the use of C1 carbon sources such as methanol, methane, formate, carbon dioxide, and carbon monoxide which are inexpensive, abundant, and often derived from industrial waste. This review highlights the potential of methanotrophs, methylotrophs, formatotrophs, and autotrophs in converting C1 substrates into PHAs under nitrogen-limited and optimized fermentation conditions. It also explores recent advances in metabolic engineering and synthetic biology to enhance PHA yields and tailor polymer properties. Despite challenges such as low productivity, substrate toxicity, low metabolic capacity, low enzyme kinetics, high production cost and limited genetic tools, progress in microbial engineering, bioprocess development, and renewable energy integration is steadily advancing the commercial viability of C1-based PHA production. This approach offers a promising path toward circular bioeconomy solutions and environmentally friendly plastic alternatives.