%0 Journal Article %A Shimizu, Satoru %A Ueno, Akio %A Tamamura, Shuji %A Naganuma, Takeshi %A Kaneko, Katsuhiko %T Methanoculleus horonobensis sp. nov., a methanogenic archaeon isolated from a deep diatomaceous shale formation %D 2013 %J International Journal of Systematic and Evolutionary Microbiology, %V 63 %N Pt_11 %P 4320-4323 %@ 1466-5034 %R https://doi.org/10.1099/ijs.0.053520-0 %I Microbiology Society, %X A methanogenic organism from the domain Archaea , designated strain T10T, was isolated from groundwater sampled from a deep diatomaceous shale formation located in Horonobe, Hokkaido, Japan. The strain utilized H2/CO2 and formate as substrates for methanogenesis. Cells were strictly anaerobic, Gram-negative-staining, flagellated, irregular coccoids, 0.7–1.6 µm in diameter, and occurred singly. The strain grew at 25–45 °C (optimum 37–42 °C), at pH 5.8–8.2 (optimum pH 6.7–6.8) and in the presence of 0–1.3 M NaCl (optimum 0.1–0.2 M NaCl). The G+C content of the genomic DNA was 62.9 mol%. 16S rRNA gene sequencing revealed that, although the strain is a member of the genus Methanoculleus , it clearly differed from all described species of this genus (95.5–98.3 % sequence similarity). Values for DNA–DNA hybridization with type strains of closely related Methanoculleus species were less than 50 %. Phenotypic and phylogenetic features of strain T10T clearly indicate that it represents a novel species of the genus Methanoculleus , for which the name Methanoculleus horonobensis sp. nov. is proposed. The type strain is T10T ( = DSM 21626T = JCM 15517T). %U https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.053520-0