Reclassification of Bacillus saliphilus as Alkalicoccus saliphilus gen. nov., comb. nov., and description of Alkalicoccus halolimnae sp. nov., a moderately halophilic bacterium isolated from a salt lake.

Abstract

A Gram-stain-positive, cocci-shaped, non-spore-forming and moderately halophilic bacterium, designed BZ-SZ-XJ29T, was isolated from a salt lake of China. On the basis of 16S rRNA gene sequence similarity, the closest phylogenetic relatives were Bacillus saliphilus 6AGT (97.3 % 16S rRNA gene sequence similarity) and five other species of the genus Bacillus(95.4-96.3 %). However, strain BZ-SZ-XJ29T shared only 89.5 % 16S rRNA gene sequence similarity with Bacillus subtilis subsp. subtilis DSM 10T, indicating that this isolate might not be a member of the genus Bacillus. The genomic DNA G+C content was 40.0 mol% (Tm). The DNA-DNA relatedness value with B. saliphilus 6AGT was 45±2 %. Strain BZ-SZ-XJ29T formed yellow pigment and grew in the presence of 0.74-4.15 M Na+ [optimum 1.42-2.10 M Na+], at pH 6.0-10.5 (optimum pH 7.5), and at 5-41 °C (optimum 33 °C). The predominant (>10 %) fatty acids were anteiso-C15 : 0 and anteiso-C15 : 0. The dominant polar lipids consisted of diphosphatidylglycerol and the respiratory quinone was menaquinone-7 (MK-7). The peptidoglycan type of the cell wall was A1γ, based on meso-diaminopimelic acid as the diagnostic diamino acid. On the basis of the combined phylogenetic data, phenotypic features and chemotaxonomic properties, it is proposed that B. saliphilus and strain BZ-SZ-XJ29T should be assigned to a single novel genus as two separate species. Bacillus. saliphilus is reclassified in a new genus, Alkalicoccus gen. nov., as Alkalicoccus saliphilus comb. nov., and is the type species of the new genus; the type strain of the type species is 6AGT (=DSM 15402T=ATCC BAA-957T). Strain BZ-SZ-XJ29T (=DSM 29191T=JCM 30193T=CGMCC 1.12936T) is placed in the genus Alkalicoccus as a novel species, Alkalicoccus halolimnae sp. nov.