%0 Journal Article %A Itoh, Takashi %A Miura, Tatsuki %A Sakai, Hiroyuki D. %A Kato, Shingo %A Ohkuma, Moriya %A Takashina, Tomonori %T Sulfuracidifex tepidarius gen. nov., sp. nov. and transfer of Sulfolobus metallicus Huber and Stetter 1992 to the genus Sulfuracidifex as Sulfuracidifex metallicus comb. nov. %D 2020 %J International Journal of Systematic and Evolutionary Microbiology, %V 70 %N 3 %P 1837-1842 %@ 1466-5034 %R https://doi.org/10.1099/ijsem.0.003981 %K thermoacidophilic %K sulfur oxidation %K Archaea %K solfatara %K iron oxidation %I Microbiology Society, %X Two novel, strictly aerobic, sulfur-dependent, thermoacidophilic strains, IC-006T and IC-007, were isolated from a solfataric field at Hakone Ohwaku-dani, Kanagawa, Japan. Cells of the two strains were irregular cocci with a diameter of 1.0–1.8 µm. They were strict aerobes and grew in a temperature range between 45 and 69 °C (optimally at 65 °C) and a pH range between 0.4 and 5.5 (optimally at pH 3.5). They required sulfur or a reduced sulfur compound, and sulfur was oxidized to sulfate. They grew autotrophically or mixotrophically utilizing several sugars and complex organic substances as carbon sources. The DNA G+C content was 42.4 mol%. A comparison of the 16S rRNA gene sequences among members of the order Sulfolobales indicated that they were closely related to Sulfolobus metallicus , forming an independent lineage within this order. The two isolates and Sulfolobus metallicus were also diffentiated based on their phenotypic properties from the other members of the order Sulfolobales . Detailed comparisons of the phenotypic properties and DNA–DNA hybridization study illustrated that the two isolates belong to a species different from Sulfolobus metallicus . On the basis of the phylogenetic and phenotypic comparisons, we propose a new genus and species, Sulfuracidifex tepidarius gen. nov., sp. nov. to accommodate strains IC-006T and IC-007. The type strain of Sulfuracidifex tepidarius is IC-006T (=JCM 16833T=DSM 104736T). In addition, Sulfolobus metallicus should be transferred to the new genus as Sulfuracidifex metallicus comb. nov.: the type strain is Kra23T (=DSM 6482T=JCM 9184T=NBRC 15436T). %U https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijsem.0.003981