title: Electrochemical stimulation of microbial reductive dechlorination of pentachlorophenol using solid-state redox mediator (humin) immobilization.
abstract: Immobilized solid-phase humin on a graphite electrode set at -500 mV (vs. standard hydrogen electrode) significantly enhanced the microbial reductive dechlorination of pentachlorophenol as a stable solid-phase redox mediator in bioelectrochemical systems (BESs). Compared with the suspended system, the immobilized system dechlorinated PCP at a much higher efficiency, achieving 116 μmol Cl(-)g(-1) humin d(-1). Fluorescence microscopy showed a conspicuous growth of bacteria on the negatively poised immobilized humin. Electron balance analyses suggested that the electrons required for microbial dechlorination were supplied primarily from the humin-immobilized electrode. Microbial community analyses based on 16S rRNA genes showed that Dehalobacter and Desulfovibrio grew on the immobilized humin as potential dechlorinators. These findings extend the potential of BESs using immobilized solid-phase humin as the redox mediator for in situ bioremediation, given the wide distribution of humin and its efficiency and stability as a mediator.
authors.affiliation: Department of Civil Engineering, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: EcoTopia Science Institute, Nagoya University, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Chunfang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: EcoTopia Science Institute, Nagoya University, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Li
authors.affiliation: EcoTopia Science Institute, Nagoya University, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Suzuki
authors.affiliation: Graduate School of Environmental Studies, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Daisuke D
authors.initials: DD
authors.lastname: Komatsu
authors.affiliation: Graduate School of Environmental Studies, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Urumu
authors.initials: U
authors.lastname: Tsunogai
authors.affiliation: Department of Civil Engineering, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya 464-8603, Japan; EcoTopia Science Institute, Nagoya University, Chikusa, Nagoya 464-8603, Japan. Electronic address: a-katayama@esi.nagoya-u.ac.jp.
authors.forename: Arata
authors.initials: A
authors.lastname: Katayama
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001674:Bioelectric Energy Sources / Q000382:microbiology; D058645:Denaturing Gradient Gel Electrophoresis; D004560:Electricity; D055664:Electrochemical Techniques / Q000379:methods*; D004583:Electrons; D005798:Genes, Bacterial; D054879:Halogenation / Q000187:drug effects*; D006812:Humic Substances / Q000032:analysis*; D010084:Oxidation-Reduction; D010416:Pentachlorophenol / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D006812:Humic Substances; D012336:RNA, Ribosomal, 16S; C001861:humin; D010416:Pentachlorophenol
keywords: Bioelectrochemical system; Humin; Pentachlorophenol; Redox mediator immobilization; Solid-phase electron mediator