RT Journal Article SR Electronic(1) A1 Segerer, Andreas H. A1 Trincone, Antonio A1 Gahrtz, Manfred A1 Stetter, Karl O.YR 1991 T1 Stygiolobus azoricus gen. nov., sp. nov. Represents a Novel Genus of Anaerobic, Extremely Thermoacidophilic Archaebacteria of the Order Sulfolobales JF International Journal of Systematic and Evolutionary Microbiology, VO 41 IS 4 SP 495 OP 501 DO https://doi.org/10.1099/00207713-41-4-495 PB Microbiology Society, SN 1466-5034, AB On the basis of three isolates (strains FC6T [T = type strain], FC4, and RG1) of extremely thermophilic chemolithoautotrophic archaebacteria obtained from solfataric fields on ão Miguel Island, Azores, the new genus Stygiolobus is described. These isolates grow obligately chemolithotrophically by reduction of S0 with H2 (H2-S0 lithotrophy) and are the first strictly anaerobic members of the order Sulfolobales. With a DNA G+C content of 38 mol%, the Stygiolobus isolates resemble Sulfolobus spp., which, however, are faculatively organotrophic and aerobic S0 oxidizers. The new isolates are also distinct from Acidianus spp., which resemble Stygiolobus by growing by H2-S0 lithotrophy. However, Acidianus spp. can also grow aerobically by S0 oxidation and have G+C contents of 31 mol%. At this time, only one species of the genus Stygiolobus is known, Stygiolobus azoricus sp. nov.; the type strain of S. azoricus is strain FC6 (= DSM 6296)., UL https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/00207713-41-4-495