Faster biodegradable and chemically recyclable polycaprolactone with embedded enzymes: Revealing new insights into degradation kinetics

[Display omitted] •Immobilized lipases in PCL matrix catalyse hydrolysis and subsequent biodegradation.•The materials are thermally processable including 3D printability.•Biodegradation kinetics governing organic carbon mineralization are revealed.•Biodegradation half-time (B1/2) correlates with organic carbon mineralization.•Embedded enzymes enable mild closed-loop chemical recyclability. Embedding immobilized lipase (IL) enzymes into polycaprolactone (PCL) matrix was demonstrated as a promising route to faster biodegradable and chemically recyclable PCL products. Furthermore, the materials could be thermally processed by extrusion and 3D printed by fused filament fabrication technique. The embedded-enzymes were shown to effectively accelerate the degradation of PCL under simulated industrial composting conditions and in aqueous solution in combination with external enzymes. To reveal deeper insights into the underlying mechanisms, the biodegradation kinetic parameters governing organic carbon (OC) mineralization were calculated. Furthermore, the concept of biodegradation half-life (B1/2) was introduced and correlated with the organic carbon (OC) mineralization rate of enzyme-embedded PCL films and filaments, especially under thermophilic composting conditions. This sheds light on how the incorporation of immobilized enzymes into PCL facilitates the degradation process. Furthermore, the feasibility of enzyme-catalyzed chemical recycling under mild conditions followed by enzyme-catalyzed repolymerization was demonstrated. The applied material design principle holds promise for addressing the pressing challenges associated with plastic waste, when moving forward towards a more sustainable and environmentally conscious future.