Process-Compatible Immobilization of Thermolabile Enzymes for Self-Degradable Polyesters via Industrial Melt Compounding Conditions

Abstract

Integrating thermolabile enzymes into industrial melt processing remains a key challenge for achieving programmable self-degradable plastics. Here, we demonstrate a process-compatible stabilization strategy for bio-based polyesters using immobilized Alcalase. Two approaches were compared: adsorption onto zeolite (Z-En) and entrapment within a citric acid–crosslinked carboxymethyl cellulose matrix (C-En-CA). Poly(lactic acid) (PLA) masterbatches containing 10 wt% C-En-CA retained catalytic functionality after twin-screw extrusion at temperatures up to 210 °C. Hydrolytic testing in 0.05 M Tris–HCl buffer (pH 8.0) resulted in a 10.03% mass loss after 3 weeks, confirming enzyme survival following melt compounding. When incorporated into PBAT T-die films, the C-En-CA system achieved 79.5% biodegradation within 45 days under industrial composting conditions. These results demonstrate that appropriate immobilization enables enzymatic stabilization under realistic extrusion temperatures, offering a scalable pathway toward controllable end-of-life degradation in commercially relevant biodegradable plastics. Ultimately, this study establishes a new paradigm for polymer–enzyme composites by overcoming the long-standing 200 °C thermal barrier, effectively unlocking the practical deployment of biocatalytic masterbatches in industrial manufacturing.