Dissolved organic matter mediates in the anaerobic degradation of 17α-ethinylestradiol in a coupled electrochemical and biological system.

Dissolved organic matter (DOM) can act as an electron shuttle in biogeochemical redox reactions to affect the fate of contaminants. Herein DOMs were tested for their ability to mediate in the degradation of 17α-ethinylestradiol (EE2) in a coupled electrochemical and biological system. Fulvic acid (FA) and Sigma humic acid (SHA) were found to promote degradation by the electro-domesticated micro-organisms in the coupled system. Analyses of superoxide dismutase levels, microbial community and clusters of orthologous groups of proteins showed that electrical stimulation promoted their growth and metabolism. It was confirmed that electron transfer in the coupled system was promoted in the presence of DOM as their protein-like components were converted into aromatic substances. The electrical stimulation improved the microorganisms' effectiveness in subsequent biodegradation under anaerobic condition. Stimulated micro-organisms seemed to increase their environmental tolerance and degrade EE2 effectively. These findings provide evidence about the fate of estrogens in bioelectrochemical water treatment.