Abstract
17α-Ethinylestradiol (EE2) is a potent synthetic estrogen widely present in municipal wastewater treatment plant (WWTP) effluents, posing severe risks to aquatic ecosystems due to its endocrine-disrupting properties even at trace concentrations. In this study, we isolated and characterized a novel bacterial consortium comprising Pseudomonas sp. strain JOR-1 and Rhodococcus sp. strain JOR-2 from municipal activated sludge, capable of utilizing EE2 as a sole carbon and energy source. Batch biodegradation experiments demonstrated that the consortium achieved 98.4% degradation of 10 mg/L EE2 within 72 hours under optimized environmental conditions (pH 7.5, 30°C), significantly outperforming the individual monocultures of Pseudomonas sp. (41.2%) and Rhodococcus sp. (57.6%). Liquid chromatography-mass spectrometry (LC-MS/MS) profiling identified major degradation intermediates, indicating that the metabolic pathway proceeds via initial hydroxylations of the phenolic A-ring followed by meta-cleavage. Furthermore, biosurfactant production by Pseudomonas sp. enhanced the bioaccessibility of hydrophobic EE2 to Rhodococcus sp., illustrating a mutualistic relationship. Acute toxicity assays using Daphnia magna confirmed a dramatic reduction in immobilization rates following 72 hours of treatment. When deployed in real WWTP secondary effluent, the consortium maintained high stability and achieved >91% EE2 removal. These findings highlight the prospective application of co-cultured bacterial consortia for targeted bioaugmentation in wastewater treatment facilities.
