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-Y25(T), 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 degrees (optimum 35-40 degrees C). Ubiquinone 0-8 was the predominant respiratory quinone. Polar lipids were diphosphaticlylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylamine and an unidentified phospholipid. The major cellular fatty acids were C-18:1 omega 7c, iso-C-16:0, C-16:0 and C-16:1. The genomic DNA G + C content was 58.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM-Y25(T) was most closely related to the type strain of the sole recognized species of the genus Saccharospirillum, Saccharospirillum impatiens EL-105(T) (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-Y25(T) (=CCTCC AA 207033(T) =KCTC 22169(T)) as the type strain.