(129c) High-Efficiency PET Degradation with a Two-Enzyme System Immobilized on Magnetic Nanoparticles

Wide consumption of polyethylene terephthalate (PET) at a global scale has necessitated the search for environment-friendly ways to degrade and recycle PET. Among these methods, biodegradation of PET has emerged as a promising approach for recycling PET. The dual-enzyme system PETase and MHETase, discovered in 2016 and its engineered variants have demonstrated significant potential in breaking down PET. However, their performance is severely affected due to enzyme aggregation, which leads to reduced PET degradation efficiency, especially at high enzyme concentrations. To minimize aggregation, we have proposed a method to immobilize both FAST PETase and MHETase on Magnetic Nanoparticles (Iron oxide nanoparticles) through His-tag fused with the enzymes. We immobilized both enzymes at a specific ratio to achieve complete depolymerization of PET to its monomers of TPA and EG with high efficiency which can contribute to upcycling of waste PET. We achieved a 2.5-fold higher activity for the bio-conjugates compared to the free enzymes on the PET film. This approach also enabled the reusability and enhanced stability of the enzyme bio-conjugates.