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Degradation performance and microbial community analysis of microbial electrolysis cells for erythromycin wastewater treatment

Hua, Tao, Li, Shengnan, Li, Fengxiang, Ondon, Brim Stevy, Liu, Yanwanjing, Wang, Haonan
Biochemical engineering journal 2019 v.146 pp. 1-9
Geobacter, anodes, antibiotic resistance genes, bacteria, biocathodes, biodegradation, biofilm, carbon, electrochemistry, erythromycin, high performance liquid chromatography, high-throughput nucleotide sequencing, microbial communities, microbial electrolysis cells, ribosomal DNA, scanning electron microscopy, wastewater, wastewater treatment
Antibiotics represent a major environmental health concern worldwide. In this study, a high concentration of erythromycin (ERY) was degraded by using single-chamber MECs with carbon cloth anodes. The electrochemical characteristics of MECs and the correlation with ERY were analysed. High-performance liquid chromatography analysis showed that the removal of ERY reached 99% when the influent concentration of ERY was 20 mg/L. In addition, ermG was the most common antibiotic resistance gene, whether in the reactor effluent (3.37×105 copies/μL DNA) or in the anode biofilm (0.21×105 copies/μL DNA), while ermA was not detected. The SEM images indicated that the anodic and cathodic biofilm were mature and well-constructed. High throughput sequencing of 16S rDNA gene amplicons indicated that Geobacter, as a known genus of exoelectrogenic bacteria, is very dominant in the reactor anode biofilm, with a relative abundance of 77.0%. Acetoanaerobium was widely present in the biocathode. These results indicate that MECs can be considered to be a useful and reliable technology for improving ERY biodegradation efficiency in wastewater, thus providing a meaningful economic output and efficient operation in future scale-ups.