Saccharolobus caldissimus gen. nov., sp. nov., a facultatively anaerobic iron-reducing hyperthermophilic archaeon isolated from an acidic terrestrial hot spring, and reclassification of Sulfolobus solfataricus as Saccharolobus solfataricus comb. nov. and Sulfolobus shibatae as Saccharolobus shibatae comb. nov.

A novel hyperthermophilic archaeon of strain HS-3T, belonging to the family Sulfolobaceae , was isolated from an acidic terrestrial hot spring in Hakone Ohwaku-dani, Japan. Based on 16S rRNA gene sequence analysis, the closest phylogenetic relatives of strain HS-3T were, first, Sulfolobus solfataricus (96.4 %) and, second, Sulfolobus shibatae (96.2 %), indicating that the strain belongs to the genus Sulfolobus . However, the sequence similarity...