title: Metagenome changes in the mesophilic biogas-producing community during fermentation of the green alga Scenedesmus obliquus.
abstract: A microalgal biomass offers a potential alternative to the maize silage commonly used in biogas technology. In this study, photoautotrophically grown Scenedesmus obliquus was used as biogas substrate. This microalga has a low C/N ratio of 8.5 relative to the optimum 20-30. A significant increase in the ammonium ion content was not observed. The methane content of the biogas generated from Sc. obliquus proved to be higher than that from maize silage, but the specific biogas yield was lower. Semi-continuous steady biogas production lasted for 2 months. Because of the thick cell wall of Sc. obliquus, the biomass-degrading microorganisms require additional time to digest its biomass. The methane concentration in the biogas was also high, in co-digestion (i.e., 52-56%) as in alga-fed anaerobic digestion (i.e., 55-62%). These results may be related to the relative predominance of the order Clostridiales in co-digestion and to the more balanced C/N ratio of the mixed algal-maize biomass. Predominance of the order Methanosarcinales was observed in the domain Archaea, which supported the diversity of metabolic pathways in the process.
authors.affiliation: Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary. Electronic address: roland.w@freemail.hu.
authors.forename: Roland
authors.initials: R
authors.lastname: Wirth
authors.affiliation: Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary. Electronic address: lakatos.gergely@brc.mta.hu.
authors.forename: Gergely
authors.initials: G
authors.lastname: Lakatos
authors.affiliation: Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary. Electronic address: tamas.bojti@gmail.com.
authors.forename: Tamás
authors.initials: T
authors.lastname: Böjti
authors.affiliation: Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary. Electronic address: maroti.gergely@brc.mta.hu.
authors.forename: Gergely
authors.initials: G
authors.lastname: Maróti
authors.affiliation: Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary. Electronic address: bagiz@brc.hu.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Bagi
authors.affiliation: Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary. Electronic address: kis.mihaly@brc.mta.hu.
authors.forename: Mihály
authors.initials: M
authors.lastname: Kis
authors.affiliation: Phytoplankton and Macrophyte Research Team, Balaton Limnological Institute, Klebersberg Kuno 3, H-8237 Tihany, Hungary. Electronic address: kovacs.attila@okologia.mta.hu.
authors.forename: Attila
authors.initials: A
authors.lastname: Kovács
authors.affiliation: Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary. Electronic address: acsn@brc.hu.
authors.forename: Norbert
authors.initials: N
authors.lastname: Ács
authors.affiliation: Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary. Electronic address: rakhely@brc.hu.
authors.forename: Gábor
authors.initials: G
authors.lastname: Rákhely
authors.affiliation: Department of Biotechnology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary; Department of Oral Biology and Experimental Dental Research, University of Szeged, Tisza L. krt. 64, H-6720 Szeged, Hungary. Electronic address: kovacs.kornel@brc.mta.hu.
authors.forename: Kornél L
authors.initials: KL
authors.lastname: Kovács
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D001105:Archaea / Q000378:metabolism; D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D005285:Fermentation; D054892:Metagenome; D008697:Methane / Q000378:metabolism; D019640:Methanosarcinales / Q000378:metabolism; D058086:Microalgae / Q000378:metabolism; D044444:Scenedesmus / Q000254:growth & development / Q000378:metabolism*; D012820:Silage; D003313:Zea mays / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds; D056804:Biofuels; D008697:Methane
keywords: Biogas; Metagenomics; Microalgae; Microbial community; Next-generation sequencing; Scenedesmus obliquus