Rethinking biodegradable plastics-challenges and opportunities

Biodegradable plastics have gained attention as a viable alternative to conventional plastics, with the potential to mitigate environmental pollution. In recent years, both petroleum-based and bio-based biodegradable plastics, including polylactic acid (PLA), polyhydroxyalkanoates (PHA), polycaprolactone (PCL), polybutylene succinate (PBS), polypropylene carbonate (PPC), polyvinyl alcohol (PVA), and polyglycolic acid (PGA), have been commercialized. Extensive research and development efforts have been dedicated to enhancing their mechanical performance and overall functionality. However, the biodegradability of these plastics is primarily assessed under controlled composting conditions, and many struggle to degrade effectively in real-world environments. This chapter provides a comprehensive review of the production, properties, and applications of various biodegradable plastics, with a particular emphasis on their biodegradation mechanisms under different environmental conditions. It examines enzymatic degradation pathways, microbial activity in aerobic composting, and anaerobic digestion for biogas production, as well as the effects of degradation intermediates on system stability. Additionally, it explores biodegradation in specialized environments such as marine and soil ecosystems. The discussion extends to critical challenges, including the need for specific degradation conditions, scalability, cost reduction, and the potential ecological risks of degradation byproducts. Finally, emerging opportunities for innovation and improved sustainability in biodegradable plastic development are highlighted, providing insights for future research and industrial applications.