A versatile potential Ancylobacter sp. PD-4 capable of biodegrading polyethylene microplastics and di(2-ethylhexyl) phthalate

Polyethylene microplastics (PE MPs) and the plasticizer di(2-ethylhexyl) phthalate (DEHP) frequently co-exist in agricultural soils as a consequence of the extensive use of plastic mulching films and plasticized agrochemicals, posing serious threats to soil ecosystems and food safety. Despite their widespread co-contamination, limited research has addressed their combined impact and effective biodegradation. This study investigated the effect of PE MPs and DEHP co-occurrence on soil microbial communities and identified novel bacterial strains capable of degrading both substrates. Microcosm experiments revealed that while co-contamination did not significantly alter microbial community composition, it delayed PE MP degradation. Fifteen bacterial strains were isolated from contaminated soils, among which Ancylobacter sp. PD-4 demonstrated high degradative potential, achieving 14.7 % PE MP degradation after 60 days and 60.7 % DEHP degradation after 7 days. Scanning electron microscope and elemental analysis confirmed polymer degradation, with increased O/C ratios and surface damage, and FTIR revealed oxidative modification and the formation of carbonyl and unsaturated groups indicative of chain scission. Genomic analysis revealed key genes encoding enzymes such as laccase, alkane monooxygenase, carboxylesterase, and phthalate dioxygenase. Metabolite profiling and genome annotation suggested that PE MPs were degraded via oxidative depolymerization followed by β-oxidation, while DEHP degradation proceeded through both protocatechuate and benzoate pathways. This study provides the first evidence of Ancylobacter sp. exhibiting dual activity toward both PE MPs and DEHP. These findings demonstrate the potential of Ancylobacter sp. PD-4 as a promising candidate for the development of sustainable bioremediation strategies for plastic and plasticizer co-contamination in agricultural environments.