The potential of Cupriavidus sp. DF5525 degrading high concentrations of p-dichlorobenzene

p-Dichlorobenzene (p-DCB), a persistent halogenated pollutant with regulatory thresholds of up to 200 mg/kg in industrial soils in China, poses significant environmental and health risks. Current bioremediation strategies are limited by poor microbial tolerance to high p-DCB concentrations (200-1000 mg/kg). Here, we report Cupriavidus sp. DF5525, a novel strain capable of degrading p-DCB at unprecedented levels (3 g/L tolerance, 98.22 % removal of 180 mg/L in 10 days). Genome analysis revealed a plasmid-encoded pathway for p-DCB mineralization, including chlorobenzene dioxygenase and chlorocatechol degradation genes. In soil bioaugmentation trials, DF5525 achieved 81.7 % removal of 500 mg/kg p-DCB within 30 days, while its relative abundance surged from 0.4 % to 11.69 %, indicating robust colonization. Co-occurrence network analysis revealed 84.23 % positive microbial interactions, suggesting p-DCB degradation might involve in the bacterial commensalism or mutualism. These findings highlight the potential of Cupriavidus sp. DF5525 as a promising candidate for bioremediation of high-concentration p-DCB contamination, offering an effective and sustainable solution for recalcitrant halogenated pollutant remediation, with direct implications for industrial soil cleanup.