Saccharospirillum salsuginis sp. nov., a gammaproteobacterium from a subterranean brine

A novel Gram-negative, non-sporulating, moderately halophilic, facultatively alkaliphilic, catalase- and oxidase-positive, obligately aerobic bacterium, strain YIM-Y25T, was isolated from a subterranean brine sample collected from a salt mine in Yunnan, south-west China. Cells were spirilla, motile by monopolar flagella, with meso-diaminopimelic acid in the cell-wall peptidoglycan. Growth occurred with 1–15 % (w/v) NaCl (optimum 5 %), at pH 6.0–10.0 (optimum pH 8.0) and at 15–50 °C (optimum 35–40 °C). Ubiquinone Q-8 was the predominant respiratory quinone. Polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylamine and an unidentified phospholipid. The major cellular fatty acids were C18 : 1 ω7c, iso-C16 : 0, C16 : 0 and C16 : 1. The genomic DNA G+C content was 58.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM-Y25T was most closely related to the type strain of the sole recognized species of the genus Saccharospirillum, Saccharospirillum impatiens EL-105T (sequence similarity 97.0 %), and these two strains formed a robust lineage in the phylogenetic tree. The level of DNA–DNA relatedness between them was 12.6 %. The combination of phylogenetic analysis, phenotypic differences, chemotaxonomic properties and DNA–DNA hybridization data supported the view that this strain represents a novel species of the genus Saccharospirillum, for which the name Saccharospirillum salsuginis sp. nov. is proposed, with YIM-Y25T (=CCTCC AA 207033T =KCTC 22169T) as the type strain.