Desulfuribacillus alkaliarsenatis gen. nov. sp. nov., a deep-lineage, obligately anaerobic, dissimilatory sulfur and arsenate-reducing, haloalkaliphilic representative of the order Bacillales from soda lakes

An anaerobic enrichment culture inoculated with a sample of sediments from soda lakes of the Kulunda Steppe with elemental sulfur as electron acceptor and formate as electron donor at pH 10 and moderate salinity inoculated with sediments from soda lakes in Kulunda Steppe (Altai, Russia) resulted in the domination of a Gram-positive, spore-forming bacterium strain AHT28. The isolate is an obligate anaerobe capable of respiratory growth using elemental sulfur, thiosulfate (incomplete reduction) and arsenate as electron acceptor with H2, formate, pyruvate and lactate as electron donor. Growth was possible within a pH range from 9 to 10.5 (optimum at pH 10) and a salt concentration at pH 10 from 0.2 to 2 M total Na+ (optimum at 0.6 M). According to the phylogenetic analysis, strain AHT28 represents a deep independent lineage within the order Bacillales with a maximum of 90 % 16S rRNA gene similarity to its closest cultured representatives. On the basis of its distinct phenotype and phylogeny, the novel haloalkaliphilic anaerobe is suggested as a new genus and species, Desulfuribacillus alkaliarsenatis (type strain AHT28T = DSM24608T = UNIQEM U855T)