Virgibacillus kekensis sp. nov., a moderately halophilic bacterium isolated from a salt lake in China

Abstract

A Gram-positive, moderately halophilic, motile, strictly aerobic, endospore-forming, oxidase- and catalase-positive, rod-shaped bacterium, strain YIM kkny16(T), was isolated from a saline mud sample collected from the Keke salt lake in the Qaidam Basin, north-west China. This isolate grew in the presence of 0-25 % (w/v) NaCl and at pH 6.0-10.0 and 10-50 degrees C; optimum growth was observed with 10 % (w/v) NaCl and at pH 7.0 and 37 degrees C. Strain YIM kkny16(T) had meso-diaminopimelic acid as the diagnostic diamino acid, MK-7 as the predominant respiratory quinone, with a significant amount of MK-6, and anteiso-C(15 : 0), iso-C(14 : 0) and C(16 : 1)omega7c alcohol as major fatty acids. Major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The DNA G+C content was 41.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain YIM kkny16(T) was a member of the genus Virgibacillus, exhibiting sequence similarities of 94.9-97.3 % to the type strains of recognized Virgibacillus species. Strain YIM kkny16(T) could be differentiated from recognized Virgibacillus species based on phenotypic characteristics, chemotaxonomic differences, phylogenetic analysis and DNA-DNA hybridization data. On the basis of evidence from this polyphasic study, strain YIM kkny16(T) is considered to represent a novel species of the genus Virgibacillus, for which the name Virgibacillus kekensis sp. nov. is proposed. The type strain is YIM kkny16(T) (=DSM 17056(T)=CGMCC 1.6298(T)).