A comprehensive mechanism of polyester enzymatic depolymerization: A novel singular key parameter for streamlined...

Plastic pollution persists due to polymers' resistance to depolymerization, making eco-design and enzymatic recycling essential for sustainability. However, understanding plastic depolymerization is complex, and studies often separate enzymatic from non-enzymatic degradation, despite their interconnectedness in practice. This study aims to simplify this process, unifying key factors into a single mechanism using polylactide (PLA) as a model. We demonstrate that the local glass transition temperature of the soaked material (T_g^s) -a novel parameter-is the central factor enabling chain mobility for enzyme interaction, with chain mobility as the primary driver in degradation. Enzymatic hydrolysis initiates perforation, triggering non-enzymatic depolymerization when chain-end density is sufficient. This unified mechanism complements enzymologists' work, providing an innovative pathway to optimize enzymatic plastic recycling and accelerate polyester degradation under practical conditions.