Advances in immobilized enzyme systems for enhanced microplastic biodegradation: A review

The quick rise in global plastic production and consumption highlights the urgent need for advanced biological strategies to achieve efficient and sustainable degradation. Although enzymes have demonstrated significant potential for microplastic biodegradation at the laboratory scale, their direct application in industrial settings remains limited due to obstacles linked to stability, repeated use, and affordability. Immobilization of enzyme has thus developed as a useful approach to bridge this gap and enable practical large-scale deployment. Accordingly, this review critically examines recent advances in the potential of immobilized enzymes as effective tools for sustainable microplastic waste management. It further explores how different immobilization strategies influence enzyme stability and plastic degradation efficiency, as well as the diverse mechanisms by which these enzymes degrade plastics. Research trends indicate that studies on immobilized enzymes for plastic biodegradation are mainly centered on hydrolases which efficiently target ester-containing polymers and have already demonstrated potential for large-scale biodegradation processes. In contrast, immobilized oxidases, despite their considerable potential for degradation of plastics with CC backbones remain at an early stage of research due to their reliance on radical pathways and mediator systems. The discovery and characterization of extremophilic enzymes with stability under harsh conditions are expected to accelerate progress in this field. Moreover, the integration of computational approaches will provide a mechanistic understanding of the interactions between enzymes and microplastics. Developing hybrid processes that integrate enzymatic, chemical, and photochemical treatments could overcome current limitations and push this field closer to practical implementation.