A customized self-assembled synergistic biocatalyst for plastic depolymerization

The enzymatic degradation of plastic offers a green, sustainable strategy and scalable circular carbon route for solving polyester waste. Among the earlies discovered plastic-degrading enzymes are PET hydrolase (PETase) and MHET hydrolase (MHETase), which act synergistically. To promote the adsorption of enzymes on PET surfaces, increase their robustness, and enable directly depolymerization, we designed hydrophobin HFBI fused-PETase and MHETase. A customized self-assembled synergistic biocatalyst (MC@CaZn-MOF) was further developed to promote the two-step depolymerization process. The tailored catalysts showed better adhesion to the PET surface and desirable durability, retaining over 70% relative activity after incubation at pH 8.0 and 60 °C for 120 h. Importantly, MC@CaZn-MOF could directly decompose untreated AGf-PET to generate 9.5 mM TPA with weight loss over 90%. The successful implementation of a bifunctional customized catalyst makes the large-scale biocatalytic degradation of PET feasible, contributing to polymer upcycling and environmental sustainability.