Syntrophic interactions between H2-scavenging and anode-respiring bacteria can improve current density in microbial electrochemical cells

• Published in: Bioresource technology Vol. 153; pp. 245 - 253
• Main Authors: Gao, Yaohuan, Ryu, Hodon, Santo Domingo, Jorge W., Lee, Hyung-Sool
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2014; Elsevier
• Subjects: Acetates - pharmacology; Aerobiosis - drug effects; Anaerobic digester (AD); Anode-respiring bacteria (ARB); Anodes; Bacteria; Bacteria - drug effects; Bacteria - genetics; Bacteria - metabolism; Bioelectric Energy Sources - microbiology; Biofilms - drug effects; Biological and medical sciences; Biological Oxygen Demand Analysis; Biological treatment of sewage sludges and wastes; Biotechnology; Density; Electricity; Electrochemical cells; Electrodes; Environment and pollution; Fatty acids; Fatty Acids, Volatile - analysis; Fundamental and applied biological sciences. Psychology; Genes, Bacterial - genetics; High current; Homoacetogens; Hydrogen - metabolism; Industrial applications and implications. Economical aspects; Kinetics; Methane; Methane - metabolism; Methanogens; Microbial electrochemical cells (MECs); Microbial Interactions - drug effects; Microorganisms; RNA, Ribosomal, 16S - genetics; Volatilization - drug effects; Waste Disposal, Fluid; Anode-respiring bacteria (ARB); Microbial electrochemical cells (MECs); Anaerobic digester (AD); Homoacetogens; Methanogens; Syntrophy; Anode; Sewage digester; Anaerobic digestion; Methanogenic bacteria; Electrochemistry; Microorganism; Current density
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2013.11.077

•High current density (14.6A/m2) can be achieved from the MEC fed with digestate.•COD removal was improved up to 96% in the MEC.•Methane production was as small as ∼3% of removed COD.•Homoacetogens outcompeted methanogens due to the syntrophy with ARB. High current density of 10.0–14.6A/m2 and COD removal up to 96% were obtained in a microbial electrochemical cell (MEC) fed with digestate at hydraulic retention time (HRT) of 4d and 8d. Volatile fatty acids became undetectable in MEC effluent (HRT 8d), except for trivial acetate (4.16±1.86mgCOD/L). Accumulated methane only accounted for 3.42% of ΔCOD. Pyrosequencing analyses showed abundant fermenters (Kosmotoga spp.) and homoacetogens (Treponema spp.) in anolytes. In anode biofilm, propionate fermenters (Kosmotoga, and Syntrophobacter spp.), homoacetogens (Treponema spp.), and anode-respiring bacteria (ARB) (Geobacter spp. and Dysgonomonas spp.) were dominant. These results imply that syntrophic interactions among fermenters, homoacetogens and ARB would allow MECs to maintain high current density and coulombic efficiency.