Rethinking plastic waste: innovations in enzymatic breakdown of oil-based polyesters and bioplastics.

Abstract

The global accumulation of plastic waste, exceeding 360 million tonnes annually, represents a critical environmental challenge due to their widespread use and extreme recalcitrance in natural environments. Furthermore, the end-of-life processing of bioplastics, which are often marketed as eco-friendly, remains problematic, with biodegradation often requiring industrial conditions. Enzyme-based depolymerization of polyesters, such as polyethylene terephthalate (PET) and bioplastics (e.g., polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), and polyhydroxyalkanoates (PHAs)), has emerged as a promising alternative, offering a green approach to postconsumer plastic management with a reduced environmental impact and in alignment with circular economy principles. This review summarizes recent advances in enzymatic degradation of oil-derived and bio-based polyesters. Key recent developments are discussed including novel high-throughput screenings, computational workflow for improvement of PET hydrolases and de novo design of biocatalysts, microbial platforms, and enzyme-embedded self-biodegrading bioplastics. Collectively, these innovations are redefining the role of biocatalysis in tackling synthetic polymer pollution. Looking ahead, the integration of enzymatic depolymerization with upcycling pathways, standardized kinetic metrics, and one-pot bioprocesses represents a viable strategy for sustainable plastic waste valorization.