title: Methanobacterium aarhusense sp. nov., a novel methanogen isolated from a marine sediment (Aarhus Bay, Denmark).
abstract: Strain H2-LR(T), a 5-18 micro m long and 0.7 micro m wide filamentous, mesophilic, moderately halophilic, non-motile hydrogenotrophic methanogen, was isolated from marine sediment of Aarhus Bay, Denmark, 1.7 m below the sediment surface. On the basis of 16S rRNA gene comparison with sequences of known methanogens, strain H2-LR(T) could be affiliated to the genus Methanobacterium. The strain forms a distinct line of descent within this genus, with Methanobacterium oryzae (95.9 % sequence identity) and Methanobacterium bryantii (95.7 % sequence identity) as its closest relatives. The 16S rRNA-based affiliation was supported by comparison of the mcrA gene, which encodes the alpha-subunit of methyl-coenzyme M reductase. Strain H2-LR(T) grew only on H(2)/CO(2). The DNA G+C content is 34.9 mol%. Optimum growth temperature was 45 degrees C. The strain grew equally well at pH 7.5 and 8. No growth or methane production was observed below pH 5 or above pH 9. Strain H2-LR(T) grew well within an NaCl concentration range of 100 and 900 mM. No growth or methane production was observed at 1 M NaCl. At 50 mM NaCl, growth and methane production were reduced. Based on 16S rRNA gene sequence analysis, the isolate is proposed to represent a novel taxon within the genus Methanobacterium, namely Methanobacterium aarhusense sp. nov. The type strain is H2-LR(T) (=DSM 15219(T)=ATCC BAA-828(T)).
authors.affiliation: Department of Microbiology, Institute of Biological Science, Aarhus University, DK-8000 Aarhus C, Denmark.
authors.forename: Adris Georgis
authors.initials: AG
authors.lastname: Shlimon
authors.affiliation: Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Str, D-35043 Marburg, Germany.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Friedrich
authors.affiliation: Max-Planck-Institute for Marine Microbiology, Celsiusstrasse 1, D-28359 Bremen, Germany.
authors.forename: Helge
authors.initials: H
authors.lastname: Niemann
authors.affiliation: Department of Microbiology, Institute of Biological Science, Aarhus University, DK-8000 Aarhus C, Denmark.
authors.forename: Niels Birger
authors.initials: NB
authors.lastname: Ramsing
authors.affiliation: Department of Microbiology, Institute of Biological Science, Aarhus University, DK-8000 Aarhus C, Denmark.
authors.forename: Kai
authors.initials: K
authors.lastname: Finster
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D003718:Denmark; D019015:Geologic Sediments / Q000382:microbiology; D008697:Methane / Q000378:metabolism; D017014:Methanobacterium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D008697:Methane