Single-pot nanoparticle-enzyme integration enables synergistic PEG valorization for bioethanol production

Polyethylene glycol (PEG), a widely used synthetic polymer, poses significant environmental concerns due to its persistence, highlighting the need for effective degradation strategies. This study presents a novel hybrid chemo-biological system, which combines magnetic nanoparticles (Fe 3 O 4 -MNPs), hydrogen peroxide (H 2 O 2 ), and recombinant (carboxylesterase/lipase) enzymes, along with magnesium (Mg 2 ⁺) and calcium (Ca 2 ⁺) ions as cofactors, to efficiently break down and valorize PEG. The Fe 3 O 4 -MNPs / H 2 O 2 system generates hydroxyl radicals, initiating polymer depolymerization, while enzymatic catalysis further cleaves ester bonds to produce low-molecular-weight intermediates. These intermediates are then converted into ethanol through microbial fermentation, establishing a direct pathway from PEG waste to biofuel. Optimization of the process using a central composite design (CCD) revealed synergistic effects among Fe 3 O 4 -MNPs, H 2 O 2 , and divalent ions, with moderate concentrations yielding a maximum ethanol output of 1.14%, outperforming non-optimized conditions. Our findings demonstrate a proof-of-concept platform for integrating radical chemistry with biocatalysis to degrade recalcitrant polymers and enable resource recovery. This approach provides a foundation for scalable PEG valorization and contributes to the development of sustainable polymer waste management strategies.