Halomonas sabkhae sp nov., a moderately halophilic bacterium isolated from an Algerian sabkha

A novel moderately halophilic bacterium belonging to the genus Halomonas was isolated from brine samples collected from Ezzemoul sabkha in north-eastern Algeria. The cells of strain 5-3(T) were Gram-negative, rod-shaped and non-motile. The strain was catalase- and oxidase- positive and produced an exopolysaccharide. Growth occurred at NaCl concentrations of 5-25% (optimum at 7.5%), at 30-50 degrees C (optimum at 37-40 degrees C and at pH 6.0-9.0 (optimum at pH 7.5). The major fatty acids were C-12:0 3-OH, C-16: 1 omega 7C/iSO-C-15:0 2-OH, C-16: 0, C-18: 1 omega 7c and C-19: 0 omega 8c cyclo. The G + C content of the genomic DNA was 57.0 mol% (T-m). The affiliation of strain 5-3(T) with the genus Halomonas was confirmed by 16S rRNA gene sequence comparisons. The most closely related species was Halomonas halmophila, which showed a 16S rRNA gene sequence similarity of 99.7%. However, the level of DNA-DNA relatedness between the novel isolate and the related Halomonas species was less than 31.4%. On the basis of the data from this polyphasic study, strain 5-3(T) represents a novel species of the genus Halomonas, for which the name Halomonas sabkhae sp. nov. is proposed. The type strain is 5-3(T) (= CECT 7246(T) = DSM 19122(T) = LMG 24084(T)).