title: Polarity inversion of bioanode for biocathodic reduction of aromatic pollutants.
abstract: The enrichment of specific pollutant-reducing consortium is usually required prior to the startup of biocathode bioelectrochemical system (BES) and the whole process is time consuming. To rapidly establish a non-specific functional biocathode, direct polar inversion from bioanode to biocathode is proposed in this study. Based on the diverse reductases and electron transfer related proteins of anode-respiring bacteria (ARB), the acclimated electrochemically active biofilm (EAB) may catalyze reduction of different aromatic pollutants. Within approximately 12 d, the acclimated bioanodes were directly employed as biocathodes for nitroaromatic nitrobenzene (NB) and azo dye acid orange 7 (AO7) reduction. Our results indicated that the established biocathode significantly accelerated the reduction of NB to aniline (AN) and AO7 to discolored products compared with the abiotic cathode and open circuit controls. Several microbes possessing capabilities of nitroaromatic/azo dye reduction and bidirectional electron transfer were maintained or enriched in the biocathode communities. Cyclic voltammetry highlighted the decreased over-potentials and enhanced electron transfer of biocathode as well as demonstrated the ARB Geobacter containing cytochrome c involved in the backward electron transfer from electrode to NB. This study offers new insights into the rapid establishment and modularization of functional biocathodes for the potential treatment of complicated electron acceptors-coexisting wastewaters.
authors.affiliation: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yun
authors.affiliation: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: binliang@rcees.ac.cn.
authors.forename: Bin
authors.initials: B
authors.lastname: Liang
authors.affiliation: Shenyang Academy of Environmental Sciences, Shenyang 110167, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: De-Yong
authors.initials: DY
authors.lastname: Kong
authors.affiliation: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Hao-Yi
authors.initials: HY
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Zhi-Ling
authors.initials: ZL
authors.lastname: Li
authors.affiliation: Key Laboratory of Biometallurgy of Ministry of Education, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
authors.forename: Ya-Bing
authors.initials: YB
authors.lastname: Gu
authors.affiliation: Key Laboratory of Biometallurgy of Ministry of Education, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
authors.forename: Hua-Qun
authors.initials: HQ
authors.lastname: Yin
authors.affiliation: Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: ajwang@rcees.ac.cn.
authors.forename: Ai-Jie
authors.initials: AJ
authors.lastname: Wang
mesh_terms: D001391:Azo Compounds / Q000378:metabolism*; D001557:Benzenesulfonates / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D055664:Electrochemical Techniques; D004579:Electron Transport; D059013:Microbial Consortia; D009578:Nitrobenzenes / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism; D018508:Water Purification / Q000379:methods*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D009578:Nitrobenzenes; D014874:Water Pollutants, Chemical; C036077:nitrobenzene; C014722:2-naphthol orange
keywords: Bidirectional electron transfer; Biocathode; Nitroaromatics and azo dye reduction; Polarity inversion