Design of a Chitinase-Responsive, Depolymerizable Petroleum-Derived Polymer for Circular and Antifouling Materials

Petroleum-derived polymers (PDPs), including polyolefins and polyesters, combine mechanical robustness and thermal stability but persist in the environment due to chemically inert C-C backbones. Here, we report PHEVD (poly-[7-(2-hydroxyethyl)-2,4-divinyl-3-oxa-7-azabi-cyclo[3.3.0]-octane-6,8-dione]), a polymer designed to preserve PDP-relevant thermal stability and hydrophobic film performance while incorporating enzyme-addressable imide and amide motifs. Compared with polyethylene terephthalate (PET) and polyethylene (PE), PHEVD exhibits comparable thermal robustness yet undergoes rapid and near-complete depolymerization within 7 days under mild aqueous conditions in the presence of Pseudomonas aeruginosa (PAO1), with measurable degradation also observed for Chlorella vulgaris. Integrated transcriptomic, mutant, and purified-enzyme analyses implicate Chitinase-associated pathways in degradation. ¹H NMR and LC-MS confirm the disappearance of parent polymer signals and the formation of low-molecular-weight, soluble products, indicating chemical depolymerization rather than persistent microplastic fragmentation. Identified degradation products correlate with biofilm-dispersion signatures, linking controlled breakdown to functional biological outcomes. By retaining PDP-like performance during use while enabling selective, biologically triggered end-of-life conversion into soluble small molecules, PHEVD demonstrates a structure-guided strategy to reduce environmental persistence relative to conventional PDPs and advance sustainable polymer design.