title: Enrichment of specific electro-active microorganisms and enhancement of methane production by adding granular activated carbon in anaerobic reactors.
abstract: Direct interspecies electron transfer (DIET) via conductive materials can provide significant benefits to anaerobic methane formation in terms of production amount and rate. Although granular activated carbon (GAC) demonstrated its applicability in facilitating DIET in methanogenesis, DIET in continuous flow anaerobic reactors has not been verified. Here, evidences of DIET via GAC were explored. The reactor supplemented with GAC showed 1.8-fold higher methane production rate than that without GAC (35.7 versus 20.1±7.1mL-CH4/d). Around 34% of methane formation was attributed to the biomass attached to GAC. Pyrosequencing of 16S rRNA gene demonstrated the enrichment of exoelectrogens (e.g. Geobacter) and hydrogenotrophic methanogens (e.g. Methanospirillum and Methanolinea) from the biomass attached to GAC. Furthermore, anodic and cathodic currents generation was observed in an electrochemical cell containing GAC biomass. Taken together, GAC supplementation created an environment for enriching the microorganisms involved in DIET, which increased the methane production rate.
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea.
authors.forename: Jung-Yeol
authors.initials: JY
authors.lastname: Lee
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea.
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea. Electronic address: heedeung@korea.ac.kr.
authors.forename: Hee-Deung
authors.initials: HD
authors.lastname: Park
mesh_terms: D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D002606:Charcoal; D004566:Electrodes; D004579:Electron Transport; D045302:Geobacter / Q000235:genetics / Q000378:metabolism; D008697:Methane / Q000096:biosynthesis*; D017018:Methanomicrobiales / Q000235:genetics / Q000378:metabolism; D059013:Microbial Consortia / Q000235:genetics / Q000502:physiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
chemical_list: D012336:RNA, Ribosomal, 16S; D002606:Charcoal; D008697:Methane
keywords: Anaerobic digestion; Direct interspecies electron transfer; Geobacter; Granular activated carbon; Methanogenesis