Genome sequencing of a ‘Tepidibacillus infernus’ strain MBL-TLP, novel moderately thermophilic, selenate- and arsenate-respiring hydrolytic bacterium isolated from the Tautona goldmine (South Africa).. ‘Tepidibacillus infernus’

‘Tepidibacillus infernus’ strain MBL-TLP is a novel aerotolerant anaerobic, moderately thermophilic, organotrophic bacterium inhabiting in microbial mat (Tautona goldmine, South Africa). The cells of the novel strain are flagellated sporulating rods with a Gram-positive type of cell wall. The novel isolate grew at 25-58⁰C (optimum 50⁰C), pH 5.6 -8.8 (optimum 7.4) and salinity 0 - 85 g/l of NaCl (optimum 15 g/l). The isolate was able to ferment yeast extract and mono-, oligo- and polysaccharides. Phylogenetic analysis of 16S rRNA gene sequences of strain MBL-TLPT and relatives showed its affiliation with the genus Tepidibacillus. Tepidibacillus fermentans was its closest relative (97.05 % identity of 16S rRNA gene sequences). However, the novel isolate possessed phenotypic characteristics that differed significantly from those of T. fermentans, the only other recognized species of the genus Tepidibacillus. In particular, it was found that MBL-TLP was able to use arsenate, selenite and selenate as electron acceptors in the presence of acetate as electron donor. Moreover, whereas T. fermentans is able to grow with oxygen concentration up to 10 %, novel isolate demonstrated growth with atmospheric O2 concentration. The ability of strain MBL-TLP to utilize polysaccharides (starch and xanthan gum) was other considerable differentiation characteristic, possibly indicating the role of the strain as preliminary destructor of organic matter. In addition, it was able to grow on cellobiose, sucrose, xylose, but did not utilize peptone and tryptone as substrates. This study is aimed to give genomic and phylogenetic insights into these important metabolic features of ‘T. infernus’.