Pampinifervens navoyensis sp. nov., an Extremely Thermophilic Facultatively Anaerobic Chemolithoautotrophic Bacterium from a Hot Spring at the Navoi Region (Uzbekistan)

An extremely thermophilic chemolithoautotrophic strain Uz 6-8 was isolated from a hot spring in the Navoi region (Uzbekistan). Cells of strain Uz 6-8 were motile straight rods, non-spore-forming, 0.4–0.5 μm in diameter and 1.0−1.75 μm in length, with a gram-negative cell wall structure and a single lateral flagellum. The cells grew chemolithoautotrophically under aerobic conditions on thiosulfate or hydrogen in the medium containing NaHCO3, with CO2 in the gas phase. Nitrate was used as an electron acceptor during anaerobic growth on formate or hydrogen. The major fatty acids were saturated C18:0 and C20:0 with a cyclopropane moiety. The G+C content of the DNA was 47.5 mol %. Phylogenetic analysis based on comparison of 120 conserved proteins, DNA−DNA hybridization results (in silico), and genomic indices ANI and AAI indicated that Uz 6-8 belonged to a new species of the genus Pampinifervens (Aquificaceae). The name Pampinifervens navoyensis sp. nov. is proposed, with the type strain P. navoyensis Uz 6-8ᵀ. The genome contains the genes encoding the Arnon cycle, two uptake hydrogenases, and enzymes for formate oxidation, nitrate reduction, denitrification, and thiosulfate oxidation.