Surface adhesion and multienzyme pathways drive low-density polyethylene microplastic biodegradation by soil bacteria

Low-density polyethylene (LDPE) microplastics (MPs) are persistent pollutants posing significant ecological risks. While biodegradation offers a sustainable solution, the underlying bacterial adhesion and enzymatic mechanisms remain poorly defined. This study reports the first identification and characterization of Rhodococcus koreensis MFB1 and Gordonia hongkongensis MFB5 isolated from agricultural soil as LDPE‐degrading bacteria. After 30 days, R. koreensis MFB1 and G. hongkongensis MFB5 achieved 13.34% and 12.21% (w/w) LDPE MP weight reduction, respectively. Scanning electron microscopy revealed surface changes and Fourier-transform infrared spectroscopy confirmed oxidative degradation through the formation of carbonyl groups. R. koreensis MFB1, with higher cell surface hydrophobicity and more extensive biofilm formation, exhibited a faster degradation rate (k = 0.0045 day⁻¹) and shorter half-life (155.69 days) than G. hongkongensis MFB5 (k = 0.0040 day⁻¹, t1/2 = 172.42 days). ABTS assays showed time-dependent extracellular laccase activity that correlates with LDPE weight loss, establishing laccase as a key catalyst for initial LDPE oxidation. GhostKOALA and KEGG Mapper genome annotation revealed a conserved LDPE‐catabolic module in both strains, comprising alkane monooxygenases, alcohol/aldehyde dehydrogenases, β-oxidation enzymes, and strain-specific multicopper oxidases. By integrating adhesion properties, kinetic modeling, enzyme activity, and pathways reconstruction, this study advances the mechanistic understanding of LDPE biodegradation for sustainable plastic bioremediation.