Reduced Microplastic Formation and Enhanced Degradation in Enzyme‐Embedded <scp>PLA</scp> , <scp>PBAT</scp> , and Their Blends: Structural, Chemical, and Ecotoxicological Evaluation

ABSTRACT This study evaluates the thermophilic biodegradation behavior of enzyme‐embedded poly (lactic acid) (EPLA), poly (butylene adipate‐co‐terephthalate) (EPBAT), and PLA–PBAT blends (E‐PLA + PBAT), in which Candida rugosa lipase (LCR) was incorporated at 1 wt% into the polymer matrices. Films were fabricated via blown film extrusion and biodegraded over 120 days of aerobic composting and 50 days of anaerobic digestion, in accordance with ISO 14855‐1 and ISO 15985. Biodegradation kinetics were monitored through CO 2 evolution and biogas production, supported by structural and chemical characterization (FTIR, DSC, TGA) and morphological analysis (SEM). Compared to neat PLA, which achieved 76.12% mineralization, EPLA reached 90.11% under aerobic conditions and showed more than 15% higher biogas yield anaerobically, indicating accelerated enzymatic depolymerisation. Microplastic (MP) characterization revealed a substantial reduction in particle residues with enzyme incorporation: neat PLA (180–220 particles/kg), PBAT (260–310), and PLA + PBAT (230–280) mainly showed fragmented residues up to 1500 μm, while EPLA exhibited only 25–30 particles/kg, mostly less than 50 μm. EPBAT and E‐PLA + PBAT also demonstrated reduced MP levels (110–140 and 90–120 particles/kg, respectively). Ecotoxicological studies (OECD 208, 222) confirmed the absence of phytotoxicity and earthworm toxicity, while elemental analysis indicated enhanced carbon mineralization and decreased heavy‐metal retention in enzyme‐embedded systems. Overall, the incorporation of LCR into compostable polyesters significantly accelerates biodegradation and minimizes microplastic formation, offering a promising approach for sustainable single‐use packaging materials.