Pontibacillus halophilus sp nov., a moderately halophilic bacterium isolated from a sea urchin

Abstract

A Gram-positive-staining, moderately halophilic, strictly aerobic, catalase- and oxidase-positive, rod-shaped bacterium, designated strain JSM 076056(T), was isolated from a sea urchin collected from the South China Sea. Cells were motile by means of peritrichous flagella and formed ellipsoidal endospores lying in subterminal swollen sporangia. Strain JSM 076056(T) was able to grow at salinities of 2-25% (w/v) total salts and at pH 6.0-10.0 and 15-40 degrees C; optimum growth was observed with 5-10% (w/v) total salts and at pH 7.0-8.0 and 25-30 degrees C. It was incapable of growing with NaCl as the sole salt. meso-Diaminopimelic acid was present in the cell-wall peptidoglycan. The major cellular fatty acids were iso-C-15:0, iso-C-16:0, iso-C-14:0, anteiso-C-15:0 and C-16:1 omega 7c alcohol. The predominant respiratory quinone was MK-7 and the genomic DNA G+C content was 45.5 mol%. A phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 076056(T) belonged to the family Bacillaceae and was related most closely to the type strains of the two recognized species of the genus Pontibacillus, namely Pontibacillus chungwhensis BH030062(T) (96.4% sequence similarity) and Pontibacillus marinus BH030004(T) (96.2%); these three strains formed a robust cluster in the phylogenetic tree. In combination, the phylogenetic, phenotypic and chemotaxonomic data indicate that strain JSM 076056(T) represents a novel species of the genus Pontibacillus, for which the name Pontibacillus halophilus sp. nov. is proposed. The type strain is JSM 076056(T) (=CCTCC AA 207029(T) =DSM 19796(T) =KCTC 13190(T))