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

Abstract

A Gram-staining-positive, moderately halophilic bacterium, designated strain BH097T, 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 BH097T 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 BH097T was shown to belong to the genus Gracilibacillus within the phylum Firmicutes , and showed closest sequence similarity to Gracilibacillus saliphilus DSM 19802T (95.8 %), Gracilibacillus thailandensis TP2-8T (95.6 %), Gracilibacillus boraciitolerans DSM 17256T (95.5 %), ‘Gracilibacillus quinghaiensis’ DSM 17858 (95.4 %) and Gracilibacillus halophilus DSM 17856T (95.2 %). The DNA G+C content of this novel isolate was 37.9 mol%. The major cellular fatty acids of strain BH097T were anteiso-C15 : 0, iso-C15 : 0 and C16 : 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 BH097T represents a novel species of the genus Gracilibacillus for which the name Gracilibacillus bigeumensis sp. nov. is proposed. The type strain is BH097T ( = KCTC 13130T = DSM 19028T).