Synergistic degradation of polyethylene by a restructured bacterial consortium isolated from marine plastic debris

Polyethylene (PE) remains environmentally persistent due to its inert backbone and high molecular weight, with biodegradation hindered by low efficiency and unclear community-level mechanisms. In this study, we reconstructed a synthetic consortium, Z123, comprising Nitratireductor sp. Z-1 and Gordonia spp. Z-2 and Z-3 isolated from a consistent enrichment system. Z123 achieved 9.98% weight loss and 50.88% molecular weight reduction within 30 days, outperforming most consortia degrading pristine low-density polyethylene (LDPE). Integrated genomic and proteomic analyses suggested functional differentiation among consortium members involving oxidative activation, chain scission, and downstream metabolism. Gas chromatography-mass spectrometry (GC-MS) analysis further detected putative LDPE-associated extracellular compounds consistent with oxidative polymer modification. Recombinant MCO1 and Lcp3 modified LDPE in vitro, and their combined application caused greater depolymerization than either enzyme at the corresponding half dose, suggesting complementary catalytic contributions. Collectively, these results indicate that functional differentiation and cooperative interactions contribute to enhanced LDPE degradation by Z123. This work provides mechanistic insights into consortium-based plastic biodegradation and supports the rational design of microbial platforms for plastic waste management.