title: Dissolved organic matter as a terminal electron acceptor in the microbial oxidation of steroid estrogen.
abstract: Steroid estrogen in natural waters may be biodegraded by quinone-reducing bacteria, dissolved organic matter (DOM) may serve as a terminal electron acceptor in this process. The influence of temperature, pH, dissolved oxygen and light illumination on the reduction efficiency of anthraquinone-2-disulfonate (AQS) was investigated using 17β-estradiol (E2) as the target species. The optimum reduction conditions were found to be in the dark under anaerobic conditions at pH 8.0 and 30 °C. Quinone-reducing bacteria can use the quinone structure of DOM components as a terminal electron acceptor coupling with microbial growth to promote biodegradation. Compared with other DOM models, AQS best stimulated E2 biodegradation and the mediating effect was improved as the AQS concentration increased from 0 to 0.5 mM. However, further increase had an inhibiting effect. Natural DOM containing lake humic acid (LHA) and lake fulvic acid (LFA) had a very important accelerating effect on the degradation of E2, the action mechanism of which was consistent with that defined using DOM models. The natural DOM contained more aromatic compounds, demonstrating their greater electron-accepting capacity and generally more effective support for microorganism growth and E2 oxidation than Aldrich humic acid (HA). These results provide a more comprehensive understanding of microbial degradation of steroid estrogens in anaerobic environments and confirm DOM as an important terminal electron acceptor in pollutant transformation.
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, PR China.
authors.forename: Lipeng
authors.initials: L
authors.lastname: Gu
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, PR China. Electronic address: huangbin@kmust.edu.cn.
authors.forename: Bin
authors.initials: B
authors.lastname: Huang
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, PR China.
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, PR China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Ma
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, PR China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Pan
mesh_terms: D001421:Bacteria, Anaerobic / Q000254:growth & development* / Q000378:metabolism; D001673:Biodegradation, Environmental; D004579:Electron Transport; D004958:Estradiol / Q000032:analysis* / Q000378:metabolism; D004967:Estrogens / Q000032:analysis* / Q000378:metabolism; D006812:Humic Substances / Q000032:analysis*; D060106:Lakes / Q000737:chemistry / Q000382:microbiology; D008962:Models, Theoretical; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism
chemical_list: D004967:Estrogens; D006812:Humic Substances; D014874:Water Pollutants, Chemical; D004958:Estradiol
keywords: 17β-estradiol; Bacteria; Biodegradation; Dissolved organic matter; Electron acceptor; Quinone