Understanding methane bioelectrosynthesis from carbon dioxide in a two-chamber microbial electrolysis cells (MECs) containing a carbon biocathode. (June 2015)

• Record Type: Journal Article
• Authors: Zhen, Guangyin; Kobayashi, Takuro; Lu, Xueqin; Xu, Kaiqin
• Is Part Of: Bioresource technology. Volume 186(2015)
• Page Start: 141
• Page End: 148
• Publication Date: 2015-06
• Subjects: Microbial electrolysis cells -- CO2 reduction -- Methane production -- Electron transfer -- Electromethanogenesis; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2015.03.064
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: A two-chamber microbial electrolysis cells was developed for the reduction of CO2 . Biocathode as electron donor was the vital driving force for electromethanogenesis. FISH analysis confirmed the mechanisms of direct electron transfer. Multiple pathways of electron transfer between cell-electrode were proposed. Abstract: To better understand the underlying mechanisms for methane bioelectrosynthesis, a two-chamber MECs containing a carbon biocathode was developed and studied. Methane production substantially increased with increasing cathode potential. Considerable methane yield was achieved at a poised potential of −0.9 V (vs. Ag/AgCl), reaching 2.30 ± 0.34 mL after 5 h of operation with a faradaic efficiency of 24.2 ± 4.7%. Confirmatory tests done at 0.9 V by switching the type of flushed substrates (CO2 /N2 ) or the electrical exposure modes (ON/OFF) demonstrated that cathode serving as an electron donor was the vital driving force for methanogenesis occurring at microbe–electrode surface. Fluorescence in situ hybridization reveled Methanobacteriaceae (particularly Methanobacterium ) was the predominant methanogens, supporting the mechanisms of direct electron transfer between cell-electrode. Additionally, the analysis of scanning electron microscope confirmed that the multiple pathways of electron transfer, including direct cathode-to-cell, interspecies exchange and semi-conductive conduits all together ensured the successful electromethanogenesis process.