Methanobacterium paludis sp. nov. and a novel strain of Methanobacterium lacus isolated from northern peatlands.
Two mesophilic, hydrogenotrophic methanogens, designated strains SWAN1T and AL-21, were isolated from two contrasting peatlands: a near circumneutral temperate minerotrophic fen in New York State, USA, and an acidic boreal poor fen site in Alaska, USA, respectively. Cells of the two strains were rod-shaped, non-motile, stained Gram-negative and resisted lysis with 0.1% SDS. Cell size was 0.6×1.5-2.8 µm for strain SWAN1T and 0.45-0.85×1.5-35 µm for strain AL-21. The strains used H2/CO2 but not formate or other substrates for methanogenesis, grew optimally around 32-37 °C, and their growth spanned through a slightly low to neutral pH range (4.7-7.1). Strain AL-21 grew optimally closer to neutrality at pH 6.2, whereas strain SWAN1T showed a lower optimal pH at 5.4-5.7. The two strains were sensitive to NaCl with a maximal tolerance at 160 mM for strain SWAN1T and 50 mM for strain AL-21. Na2S was toxic at very low concentrations (0.01-0.8 mM), resulting in growth inhibition above these values. The DNA G+C content of the genomes was 35.7 mol% for strain SWAN1T and 35.8 mol% for strain AL-21. Phylogenetic analysis of the 16S rRNA gene sequences showed that the strains are members of the genus Methanobacterium. Strain SWAN1T shared 94-97% similarity with the type strains of recognized species of the genus Methanobacterium, whereas strain AL-21 shared 99% similarity with Methanobacterium lacus 17A1T. On the basis of phenotypic, genomic and phylogenetic characteristics, strain SWAN1T (=DSM 25820T=JCM 18151T) is proposed as the type strain of a novel species, Methanobacterium paludis sp. nov., while strain AL-21 is proposed as a second strain of Methanobacterium lacus.
School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.
Hinsby
H
Cadillo-Quiroz
Department of Biology, Appalachian State University, Boone, NC 28608, USA.
Suzanna L
SL
Bräuer
Department of Biology, Appalachian State University, Boone, NC 28608, USA.
Noah
N
Goodson
Department of Natural Resources, Cornell University, Ithaca, NY 14853, USA.
Joseph B
JB
Yavitt
Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.
Stephen H
SH
Zinder
D000413:Alaska; D015373:Bacterial Typing Techniques; D001482:Base Composition; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D017014:Methanobacterium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009518:New York; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S