Abstract Authors
Lehlohonolo B Qhanya - Centre for Applied Food Sustainability and Biotechnology (CAFSaB), Central University of Technology
Olga de Smidt - Centre for Applied Food Sustainability and Biotechnology (CAFSaB), Central University of Technology
Abidemi O Ojo - Centre for Applied Food Sustainability and Biotechnology (CAFSaB), Central University of Technology
Errol Cason - Department of Animal Sciences, University of the Free State
Gabre Kemp - Department of Microbiology and Biochemistry, University of the Free State
Abstract Description
Endocrine-disrupting chemicals (EDCs) represent an emerging group of contaminants of serious environmental concern due to their ability to interfere with hormonal regulation in organisms, affecting growth, reproduction, and development. EDCs, such as atrazine (ATZ), bisphenol A (BPA), triclosan (TCS), and the synthetic estrogen 17α-ethinylestradiol (EE2), are continuously released into aquatic environments through municipal and industrial effluents. Their persistence in treated effluents and subsequent discharge into natural water bodies poses long-term ecological and public health risks. This study investigated the ability of indigenous microbial consortia enriched from a wastewater stabilisation pond (WSP) system in Bloemfontein, South Africa, to remove these four representative EDCs under controlled laboratory conditions. Maturation-pond water from the WSP served as the inoculum and was incubated in modified mineral salts medium (MSM) containing a mixture of ATZ, BPA, EE2, and TCS (10 mg/L each) as the sole carbon and energy sources. The enrichment cultures were maintained at 26 °C for 35 days, with regular sampling. Microbial proliferation was assessed through optical density (OD600 nm) and total plate counts, while community composition was examined by 16S rRNA gene sequencing using PacBio technology. Liquid chromatography–tandem mass spectrometry (LC-MS/MS) was used to evaluate the removal of EDCs. Microbial growth increased markedly within the first two weeks. There was a shift in community structure following enrichment, with the dominance of Achromobacter, Stenotrophomonas, and Pseudomonas species. LC-MS/MS analysis revealed compound-specific removal patterns. EE2 and BPA were rapidly removed, with removals exceeding 90 % within 14 days. ATZ exhibited partial removal (66 %), while TCS data were inconclusive due to matrix interference. In conclusion, the indigenous pond microorganisms adapted to EDC-supplemented media and these enriched indigenous microbial consortia enhanced the removal of selected EDCs. The combined microbial and LC-MS/MS approach provided insights into both biological adaptation and chemical removal.