title: Ex-situ biogas upgrading and enhancement in different reactor systems.
abstract: Biogas upgrading is envisioned as a key process for clean energy production. The current study evaluates the efficiency of different reactor configurations for ex-situ biogas upgrading and enhancement, in which externally provided hydrogen and carbon dioxide were biologically converted to methane by the action of hydrogenotrophic methanogens. The methane content in the output gas of the most efficient configuration was >98%, allowing its exploitation as substitute to natural gas. Additionally, use of digestate from biogas plants as a cost efficient method to provide all the necessary nutrients for microbial growth was successful. High-throughput 16S rRNA sequencing revealed that the microbial community was resided by novel phylotypes belonging to the uncultured order MBA08 and to Bacteroidales. Moreover, only hydrogenotrophic methanogens were identified belonging to Methanothermobacter and Methanoculleus genera. Methanothermobacter thermautotrophicus was the predominant methanogen in the biofilm formed on top of the diffuser surface in the bubble column reactor.
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark. Electronic address: panak@env.dtu.dk.
authors.forename: Panagiotis G
authors.initials: PG
authors.lastname: Kougias
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark; Department of Agronomy, Food, Natural Resources, Animal and Environment (DAFNAE), Viale dell'Università, 16, 35020 Legnaro (Padova), Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Treu
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
authors.forename: Daniela Peñailillo
authors.initials: DP
authors.lastname: Benavente
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
authors.forename: Kanokwan
authors.initials: K
authors.lastname: Boe
authors.affiliation: Department of Biology, University of Padua, Via U. Bassi 58/b, 35121 Padova, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Campanaro
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
authors.forename: Irini
authors.initials: I
authors.lastname: Angelidaki
mesh_terms: D018441:Biofilms; D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods; D002245:Carbon Dioxide / Q000378:metabolism; D004867:Equipment Design; D059014:High-Throughput Nucleotide Sequencing; D006859:Hydrogen / Q000378:metabolism; D008697:Methane / Q000096:biosynthesis; D019638:Methanomicrobiaceae / Q000235:genetics; D059013:Microbial Consortia / Q000235:genetics / Q000502:physiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D056804:Biofuels; D012336:RNA, Ribosomal, 16S; D002245:Carbon Dioxide; D006859:Hydrogen; D008697:Methane
keywords: Anaerobic digestion; Biogas upgrade; Enhancement; Hydrogenotrophic methanogenesis; Methane