Biodegradation of phthalates by a newly isolated strain Stenotrophomonas maltophilia WM-8: Degradation efficiency, influencing factors, mechanism

In this study, focusing on the phthalates (PAEs) pollution situation dominated by Dibutyl phthalate (DBP) - Di-2-ethylhexyl phthalate (DEHP) compound pollution in the environment, a novel PAEs-degrading strain Stenotrophomonas maltophilia WM-8 was isolated from the soil of a plastic greenhouse. Under the combined pollution stress of 200 mg/L PAEs (100 mg/L DBP+100 mg/L DEHP), WM-8 demonstrated the capability to degrade over 95% of DBP and DEHP within 5 days, and its efficient degradation performance was maintained across a wide range of environmental conditions (pH 6–9, NaCl 0.75–20 g/L, PAEs 200–600 mg/L). SEM and FTIR analyses indicated that PAEs exerted a stress effect on WM-8, leading to the production of a substantial number of proteins and phospholipids, which facilitated the degradation process. UPLC-MS analysis revealed 10 degradation intermediates, and the potential degradation pathways involved deesterification reactions, β-oxidation reactions and transesterification reactions. These findings provide new insights into the bioremediation of PAEs in combined pollution scenarios.