Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons
Bioelectrochemical systems (BESs) are regarded as a promising approach for the enhanced dechlorination of chlorinated aliphatic hydrocarbons (CAHs). However, the electron distribution and transfer considering dechlorination, methanogenesis, and other bioprocesses in these systems are little understo...
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doaj-68a0baea2054412e93f640dafeeb8fce2020-11-25T02:20:11ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2018-09-01910.3389/fmicb.2018.02306416369Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic HydrocarbonsFan Chen0Zhiling Li1Jiaqi Yang2Bin Liang3Cong Huang4Weiwei Cai5Jun Nan6Aijie Wang7Aijie Wang8State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, ChinaState Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, ChinaState Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, ChinaKey Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, ChinaState Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, ChinaState Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, ChinaState Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, ChinaState Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, ChinaKey Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, ChinaBioelectrochemical systems (BESs) are regarded as a promising approach for the enhanced dechlorination of chlorinated aliphatic hydrocarbons (CAHs). However, the electron distribution and transfer considering dechlorination, methanogenesis, and other bioprocesses in these systems are little understood. This study investigated the electron fluxes in biocathode BES performing dechlorination of three typical CAHs, 1,1,2,2-tetrachloroethene (PCE), 1,1,2-trichloroethene (TCE) and 1,2-dichloroethane (1,2-DCA). Anaerobic sludge was inoculated to cathode and biocathode was acclimated by the direct acclimation and selection. The constructed biocathode at −0.26 V had significantly higher dechlorination efficiency (E24h > 99.0%) than the opened circuit (E24h of 17.2–27.5%) and abiotic cathode (E24h of 5.5–10.8%), respectively. Cyclic voltammetry analysis demonstrated the enhanced cathodic current and the positive shift of onset potential in the cathodic biofilm. Under autotrophic conditions with electrons from the cathode as sole energy source (columbic efficiencies of 80.4–90.0%) and bicarbonate as sole carbon source, CAHs dechlorination efficiencies were still maintained at 85.0 ± 2.0%, 91.4 ± 1.8%, and 84.9 ± 3.1% for PCE, TCE, and 1,2-DCA, respectively. Cis-1,2-dichloroethene was the final product for PCE and TCE, while 1,2-DCA went through a different dechlorination pathway with the non-toxic ethene as the final metabolite. Methane was the main by-product of the heterotrophic biocathode, and methane production could be enhanced to some extent by electrochemical stimulation. The various electron fluxes originating from the cathode and oxidation of organic substrates might be responsible for the enhanced CAHs dechlorination, while methane generation and bacterial growth would probably reduce the fraction of electrons provided for CAH dechlorination. The study deals with the dechlorination and competitive bioprocesses in CAH-dechlorinating biocathodes with a focus on electron fluxes.https://www.frontiersin.org/article/10.3389/fmicb.2018.02306/fullbioelectrochemical systemsbiocathodechlorinated aliphatic hydrocarbonsdechlorination characteristicselectron fluxes |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Fan Chen Zhiling Li Jiaqi Yang Bin Liang Cong Huang Weiwei Cai Jun Nan Aijie Wang Aijie Wang |
spellingShingle |
Fan Chen Zhiling Li Jiaqi Yang Bin Liang Cong Huang Weiwei Cai Jun Nan Aijie Wang Aijie Wang Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons Frontiers in Microbiology bioelectrochemical systems biocathode chlorinated aliphatic hydrocarbons dechlorination characteristics electron fluxes |
author_facet |
Fan Chen Zhiling Li Jiaqi Yang Bin Liang Cong Huang Weiwei Cai Jun Nan Aijie Wang Aijie Wang |
author_sort |
Fan Chen |
title |
Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons |
title_short |
Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons |
title_full |
Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons |
title_fullStr |
Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons |
title_full_unstemmed |
Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons |
title_sort |
electron fluxes in biocathode bioelectrochemical systems performing dechlorination of chlorinated aliphatic hydrocarbons |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Microbiology |
issn |
1664-302X |
publishDate |
2018-09-01 |
description |
Bioelectrochemical systems (BESs) are regarded as a promising approach for the enhanced dechlorination of chlorinated aliphatic hydrocarbons (CAHs). However, the electron distribution and transfer considering dechlorination, methanogenesis, and other bioprocesses in these systems are little understood. This study investigated the electron fluxes in biocathode BES performing dechlorination of three typical CAHs, 1,1,2,2-tetrachloroethene (PCE), 1,1,2-trichloroethene (TCE) and 1,2-dichloroethane (1,2-DCA). Anaerobic sludge was inoculated to cathode and biocathode was acclimated by the direct acclimation and selection. The constructed biocathode at −0.26 V had significantly higher dechlorination efficiency (E24h > 99.0%) than the opened circuit (E24h of 17.2–27.5%) and abiotic cathode (E24h of 5.5–10.8%), respectively. Cyclic voltammetry analysis demonstrated the enhanced cathodic current and the positive shift of onset potential in the cathodic biofilm. Under autotrophic conditions with electrons from the cathode as sole energy source (columbic efficiencies of 80.4–90.0%) and bicarbonate as sole carbon source, CAHs dechlorination efficiencies were still maintained at 85.0 ± 2.0%, 91.4 ± 1.8%, and 84.9 ± 3.1% for PCE, TCE, and 1,2-DCA, respectively. Cis-1,2-dichloroethene was the final product for PCE and TCE, while 1,2-DCA went through a different dechlorination pathway with the non-toxic ethene as the final metabolite. Methane was the main by-product of the heterotrophic biocathode, and methane production could be enhanced to some extent by electrochemical stimulation. The various electron fluxes originating from the cathode and oxidation of organic substrates might be responsible for the enhanced CAHs dechlorination, while methane generation and bacterial growth would probably reduce the fraction of electrons provided for CAH dechlorination. The study deals with the dechlorination and competitive bioprocesses in CAH-dechlorinating biocathodes with a focus on electron fluxes. |
topic |
bioelectrochemical systems biocathode chlorinated aliphatic hydrocarbons dechlorination characteristics electron fluxes |
url |
https://www.frontiersin.org/article/10.3389/fmicb.2018.02306/full |
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