Gracilibacillus bigeumensis sp. nov., a moderately halophilic bacterium from solar saltern soil

Abstract

A Gram-staining-positive, moderately halophilic bacterium, designated strain BH097(T), was isolated from solar saltern soil of Bigeum Island in south-west Korea. Cells were motile rods, producing spherical endospores at a terminal position in swollen sporangia. Strain BH097(T) was strictly aerobic, grew at pH 5.5-9.5 (optimum, pH 8.0), at 10-52 °C (optimum, 37 °C) and at salinities of 1-22% (w/v) NaCl (optimum, 7% NaCl). On the basis of 16S rRNA gene sequence analysis, strain BH097(T) was shown to belong to the genus Gracilibacillus within the phylum Firmicutes, and showed closest sequence similarity to Gracilibacillus saliphilus DSM 19802(T) (95.8%), Gracilibacillus thailandensis TP2-8(T) (95.6%), Gracilibacillus boraciitolerans DSM 17256(T) (95.5%), 'Gracilibacillus quinghaiensis' DSM 17858 (95.4%) and Gracilibacillus halophilus DSM 17856(T) (95.2%). The DNA G+C content of this novel isolate was 37.9 mol%. The major cellular fatty acids of strain BH097(T) were anteiso-C(15:0), iso-C(15:0) and C(16:0), and its polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol two unknown phospholipids and a glycolipid. The isoprenoid quinone was MK-7, and the peptidoglycan type was A1γ, with meso-diaminopimelic acid as the diagnostic diamino acid. On the basis of polyphasic evidence from this study, strain BH097(T) represents a novel species of the genus Gracilibacillus for which the name Gracilibacillus bigeumensis sp. nov. is proposed. The type strain is BH097(T) ( = KCTC 13130(T) = DSM 19028(T)).