title: Accelerated reduction of chlorinated nitroaromatic antibiotic chloramphenicol by biocathode.
abstract: Chlorinated nitroaromatic antibiotic chloramphenicol (CAP) is a priority pollutant in wastewaters. A fed-batch bioelectrochemical system (BES) with biocathode with applied voltage of 0.5 V (served as extracellular electron donor) and glucose as intracellular electron donor was applied to reduce CAP to amine product (AMCl2). The biocathode BES converted 87.1 ± 4.2% of 32 mg/L CAP in 4 h, and the removal efficiency reached 96.0 ± 0.9% within 24 h. Conversely, the removal efficiency of CAP in BES with an abiotic cathode was only 73.0 ± 3.2% after 24 h. When the biocathode was disconnected (no electrochemical reaction but in the presence of microbial activities), the CAP removal rate was dropped to 62.0% of that with biocathode BES. Acetylation of one hydroxyl of CAP was noted exclusive in the biocatalyzed process, while toxic intermediates, hydroxylamino (HOAM), and nitroso (NO), from CAP reduction were observed only in the abiotic cathode BES. Electrochemical hydrodechlorination and dehalogenase were responsible for dechlorination of AMCl2 to AMCl in abiotic and microbial cathode BES, respectively. The cyclic voltammetry (CV) highlighted higher peak currents and lower overpotentials for CAP reduction at the biocathode compared with abiotic cathode. With the biocathode BES, antibacterial activity of CAP was completely removed and nitro group reduction combined with dechlorination reaction enhanced detoxication efficiency of CAP. The CAP cathodic transformation pathway was proposed based on intermediates analysis. Bacterial community analysis indicated that the dominate bacteria on the biocathode were belonging to α, β, and γ-Proteobacteria. The biocathode BES could serve as a potential treatment process for CAP-containing wastewater.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090, P R China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liang
authors.forename: Hao-Yi
authors.initials: HY
authors.lastname: Cheng
authors.forename: De-Yong
authors.initials: DY
authors.lastname: Kong
authors.forename: Shu-Hong
authors.initials: SH
authors.lastname: Gao
authors.forename: Fei
authors.initials: F
authors.lastname: Sun
authors.forename: Dan
authors.initials: D
authors.lastname: Cui
authors.forename: Fan-Ying
authors.initials: FY
authors.lastname: Kong
authors.forename: Ai-Juan
authors.initials: AJ
authors.lastname: Zhou
authors.forename: Wen-Zong
authors.initials: WZ
authors.lastname: Liu
authors.forename: Nan-Qi
authors.initials: NQ
authors.lastname: Ren
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wu
authors.forename: Ai-Jie
authors.initials: AJ
authors.lastname: Wang
authors.forename: Duu-Jong
authors.initials: DJ
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D019149:Bioreactors; D002701:Chloramphenicol / Q000378:metabolism*; D055664:Electrochemical Techniques; D004566:Electrodes; D010084:Oxidation-Reduction
chemical_list: D000900:Anti-Bacterial Agents; D002701:Chloramphenicol