Accelerated polyethylene biodegradation in soil through carbon nanomaterial-primed rhizospheres

Polyethylene accounts for the majority of terrestrial plastic waste, yet its chemical inertness resists natural decomposition in soil. Rhizoremediation offers a strategy that combines plant and microbe activity, but recalcitrant C-C backbones create a kinetic bottleneck that historically restricts plastic mass loss to under 3%. Here we show that engineered carbon nanomaterials prime the plant rhizosphere to breach this kinetic barrier, driving accelerated polyethylene biodegradation in soil. Multi-walled carbon nanotubes accelerated surface-layer breakdown, achieving 12.1% mass loss within 90 days, compared to less than 0.1% in abiotic controls and 0.6% in unamended soil. This nanomaterial-amended degradation was accompanied by a 97% reduction in tensile modulus, from 782.8 to 19.6 MPa, and surface oxidation, with the O 1 s/C 1s ratio increasing from 0.17 to 0.49. In deeper soil, graphene oxide sustains long-term degradation (5.8%) tightly synchronized with root penetration. Mechanistically, carbon nano-interfaces recruit pioneer degraders (Pseudolabrys and Rhodanobacter) and enrich metabolic pathways responsible for C-C bond cleavage (K00059) and intermediate detoxification (K00799). Crucially, the nanomaterials alleviate polyethylene-induced phytotoxicity, enhancing plant biomass and potentially supporting a plant-microbe interaction. These findings demonstrate that abiotic nano-interfaces can prime biological systems to dismantle persistent polymers, offering a scalable blueprint for managing soil plastic contamination.