title: Direct electron transfer from electrode to electrochemically active bacteria in a bioelectrochemical dechlorination system.
abstract: Pentachlorophenol (PCP) was dechlorinated by electrochemically active bacteria using an electrode as the direct electron donor. Dechlorination efficiency and coulombic efficiency (CE) were investigated. When hydrogen evolution reaction was eliminated by controlling the potential, both dechlorination efficiency and CE increase as the potential decreases, which implied the dechlorination was stimulated by electric current rather than hydrogen gas. Further investigation of the cyclic voltammetry characterization of the medium revealed nearly no redox mediator secreted by the bacteria. Moreover, the comparison of dechlorination experiments carried out with filtered and unfiltered medium provided convincible evidence that the dominating electron transfer mechanism for the dechlorination is direct electron transfer. Additionally, 454 pyrosequencing technique was employed to gain a comprehensive understanding of the biocathodic microbial community. The results showed Proteobacteria, Bacteroidetes and Firmicutes were the three predominant groups. This paper demonstrated the direct electron transfer mechanism could be involved in PCP dechlorination with a biocathode.
authors.affiliation: Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemical and Biological Engineering, Yuquan Campus, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Ding
authors.initials: D
authors.lastname: Liu
authors.forename: Lecheng
authors.initials: L
authors.lastname: Lei
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Qingni
authors.initials: Q
authors.lastname: Yu
authors.forename: Zhongjian
authors.initials: Z
authors.lastname: Li
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D018441:Biofilms; D004560:Electricity; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004583:Electrons; D054879:Halogenation; D010084:Oxidation-Reduction; D010416:Pentachlorophenol / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D018508:Water Purification / Q000379:methods*
chemical_list: D010416:Pentachlorophenol
keywords: 454 Pyrosequencing technology; Bioelectrochemical system; Dechlorination; Direct electron transfer; Electrochemically active bacteria