Tepidibacillus infernus sp. Nov., a moderately thermophilic, selenate-and arsenate-respiring hydrolytic bacterium isolated from a gold mine, and emended description of the genus Tepidibacillus

A novel aerotolerant anaerobic, moderately thermophilic, organotrophic bacterium, strain MBL-TLP^T, was isolated from a sample of microbial mat, developed under the flow of subsurface water in TauTona gold mine, South Africa. Cells of the new isolate were flagellated, spore-forming rods, 0.25-0.5 μm in width and 3-15 μm in length. Strain MBL-TLP^T grew in the temperature range from 25 to 58 °C, pH range from 5.6 to 8.8 and at NaCl concentration from 0 to 85 g l⁻¹. The isolate was able to ferment yeast extract and mono-, oligo-and polysaccharides, including starch and xanthan gum. The G+C content of the DNA was 35 mol%. Phylogenetic analysis of 16S rRNA gene sequences of strain MBL-TLP^T and relatives showed its affiliation to the genus Tepidibacillus. Tepidibacillus fermentans STGH^T was its closest relative (97.1% identity of 16S rRNA gene sequences). Based on phylogenetic analysis and the physiological properties of the novel isolate, we propose a novel species, Tepidibacillus infernus sp. nov., with MBL-TLP^T(=DSM 28123^T=VKM B-2949^T) as the type strain.