Acidianus sulfidivorans sp. nov., an extremely acidophilic, thermophilic archaeon isolated from a solfatara on Lihir Island, Papua New Guinea, and emendation of the genus description

A novel, extremely thermoacidophilic, obligately chemolithotrophic archaeon (strain JP7T) was isolated from a solfatara on Lihir Island, Papua New Guinea. Cells of this organism were non-motile, Gram-negative staining, irregular-shaped cocci, 0.5–1.5 µm in size, that grew aerobically by oxidation of sulfur, Fe2+ or mineral sulfides. Cells grew anaerobically using Fe3+ as a terminal electron acceptor and H2S as an electron donor but did not oxidize hydrogen with elemental sulfur as electron acceptor. Strain JP7T grew optimally at 74 °C (temperature range 45–83 °C) and pH 0.8–1.4 (pH range 0.35–3.0). On the basis of 16S rRNA gene sequence similarity, strain JP7T was shown to belong to the Sulfolobaceae, being most closely related to the type strains of Acidianus ambivalens (93.7 %) and Acidianus infernus (93.6 %). Cell-membrane lipid structure, DNA base composition and 16S rRNA gene sequence similarity data support the placement of this strain in the genus Acidianus. Differences in aerobic and anaerobic metabolism, temperature and pH range for growth, and 16S rRNA gene sequence differentiate strain JP7T from recognized species of the genus Acidianus, and an emendation of the description of the genus is proposed. Strain JP7T is considered to represent a novel species of the genus Acidianus, for which the name Acidianus sulfidivorans sp. nov. is proposed. The type strain is JP7T (=DSM 18786T=JCM 13667T).