Mondal_2025_J.Hazard.Mater_496_139414

Dibutyl phthalate (DBP), a persistent pollutant, poses serious ecological and health risks, demanding effective bioremediation strategies. This study explores DBP degradation by Paenarthrobacter ureafaciens PB10 using genomic, enzymatic, and in situ analyses. The -4 Mb genome encodes 3678 proteins, including two pht clusters, a pca cluster, and genes for gentisate, butanol, and fatty acid metabolism. Thirteen putative phthalate esterases (>30 % similarity, all with the conserved GXSXG motif) were identified; four were structurally validated and docked with DBP. One putative extracellular esterase exhibited serine esterase catalytic mechanisms by binding affinity of -4.7 kcal/mol toward DBP, with conserved serine residues. In vitro assays and GC-MS confirmed the hydrolysis of 300 mg/L DBP by extracellular extracts (134.67 nmol/mL/min), yielding hexadecanoic and octadecanoic acids, implying subsequent butanol metabolism via fatty acid pathways. In DBP-contaminated soils, PB10 removed over 94 % of the initial total DBP concentration (130 mg/kg) through a preincubation approach. Degradation followed first-order kinetics, with half-lives of 12.26 and 16.00 days in sterile and non-sterile soils, respectively. PB10 coexisted with indigenous microbes to further enhance DBP dissipation. Notably, PB10 fully inhibited DBP accumulation in rice seedlings (bioconcentration factor, BCF = 0) and alleviated phytotoxic effects, promoting seedling growth. Under controlled laboratory conditions, these results imply that PB10 has potential for DBP bioremediation and plant growth promotion; however, additional research is required to confirm its efficacy in complex agroecosystem settings.