Insect-mediated polystyrene (PS) degradation: Mechanisms, efficiency, ecological impacts, and application prospects

Plastic pollution is a critical global issue. Polystyrene (PS) is highly stable and degrades slowly, causing massive accumulation in ecosystems and severe threats to soil, marine life, and human health. Recent studies have demonstrated that the synergy between insects and their gut microbiota can achieve PS biodegradation, offering a novel green remediation approach. This paper systematically reviews insect species capable of PS degradation and the core roles of gut microbiota and their enzyme systems. It elaborates the multi-stage mechanisms of physical activation, enzymatic oxidation, depolymerization-mineralization, and bioassimilation, and analyzes influencing factors such as PS properties and insect developmental stage, along with the ecotoxicological effects and application potential of this process. Evidence confirms that insects such as Tenebrio molitor, Zophobas atratus, and Galleria mellonella oxidize and metabolize PS via symbiosis with gut microbes, leading to surface damage, molecular weight reduction, and oxygen incorporation. Part of the PS carbon is mineralized to CO₂ or assimilated into biomass. However, current research exhibits marked methodological heterogeneity, with studies differing in PS substrate forms, experimental designs, and detection endpoints, hindering cross‑study comparison of degradation efficiency. Furthermore, most studies lack standardized validation such as isotope tracing, undermining the reliability and comparability of results. Unified experimental and reporting standards, along with wider adoption of validated methods, are urgently needed to underpin future research and application.