Microbial and Enzymatic Strategies for Plastic Waste Biodegradation: Mechanistic Pathways, Environmental Challenges, and Emerging Biotechnological Strategies

Abstract

Plastic pollution has become the major global environmental problem due to the extensive accumulation and recalcitrance of synthetic polymers in terrestrial and aquatic environments. Traditional methods of plastic waste degradation, such as landfilling, incineration, and mechanical recycling, have various environmental limitations, like the production of more harmful toxic components, secondary pollutants, and inefficient waste handling. Therefore, current research is focused on more promising and environmentally sustainable alternatives for plastic waste management by microbial biodegradation. This review includes various bacterial and fungal enzymes such as PETase, MHETase, cutinase, laccase, and polyesterase associated with major stages of microbial plastic degradation, including biodeterioration, biofragmentation, bioassimilation, and mineralization. The degradation mechanism of synthetic polymers like polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyurethane (PU), polystyrene (PS), and polyvinyl chloride (PVC) are discussed along with the importance of analytical validation techniques such as FTIR, SEM, GC–MS, respirometry assays, and stable isotope probing for accurately confirming biodegradation. Additionally, the existing limitations of poor degrading efficiency, polymer recalcitrance, mixed plastic waste complexity, scaling challenges, and the gap between laboratory results and environmental application are comprehensively analyzed. Overall, the review provides a comprehensive overview of microbial and enzymatic plastic biodegradation and highlights recent advancements in metagenomics, enzyme engineering, synthetic biology, and multi‐omics approaches that helps in improving the efficiency and large‐scale industrial feasibility of microbial plastic degradation.