Oxidative Enhancement of Polystyrene Bioconversion Associated with Bio-Fenton-Type Processes in a Mesocosm-Scale Plastivore System

Abstract Sustainable plastic waste management calls for mesocosm-scale biological strategies coupling polymer depolymerization with controlled plastic-carbon transformation, yet routes for optimizing plastivore-mediated bioconversion beyond laboratory scale remain poorly defined. Here, we establish a mesocosm-scale plastivore-based platform using Tenebrio molitor larvae and show that moderate Fe supplementation increased the •OH-associated oxidative activity, accompanied by enhanced polystyrene (PS) depolymerization and PS disappearance. Under a simplified incineration-reference scenario, the estimated PS-derived carbon conversion flux corresponded to a gross avoided direct-emission potential of up to approximately 0.31 t CO2 per ton of larvae per month, without representing net life-cycle greenhouse gas mitigation. Molecular analyses showed greater oxidative functionalization, oligomer formation, and chain scission than under regular bioconversion. Quantitative •OH assays and fluorescence imaging further showed stronger intestinal •OH-associated levels, faster signal development, and earlier stabilization in the enhanced bioconversion system. Together, the evidence supports Fe-mediated enhancement of intestinal oxidative processes consistent with bio-Fenton-type reactions and identifies redox modulation as a promising and scalable strategy for plastic depolymerization and bioconversion.