Gracilibacillusmarinus sp. nov., isolated from the northern South China Sea

Two gram-positive, aerobic, spore-forming, rod-shaped bacteria, designated HB09003T and HB12160, were isolated from seawater and sediment in the northern South China Sea, respectively. Cells were found to be motile by means of peritrichous flagella. The strains were found to grow with 0–15 % (w/v) NaCl, at 10–45 °C and pH 5.0–10.7, with an optimum of 3 % NaCl, 28 °C and pH 8.5, respectively. The predominant isoprenoid quinone of strain HB09003T, selected as the representative strain, was identified as MK-7. This strain was found to possess anteiso-C15:0, iso-C15:0, anteiso-C17:0 and C16:0 as the major fatty acids. The G+C contents of strain HB09003T and HB12160 were determined to be 34.1 and 34.3 mol%, respectively. Analysis of the 16S rRNA gene sequences of the two strains showed an affiliation with the genus Gracilibacillus, with Gracilibacilluskekensis CGMCC 1.10681T (similarity of 97.4, 98.0 %, respectively) and Gracilibacillusureilyticus CGMCC 1.7727T (similarity of 97.1, 97.8 %, respectively) as their closest relatives. The DNA–DNA hybridization values between strain HB09003T and the two type strains were 42.2 and 54.1 %, respectively. On the basis of phenotypic and genotypic data, strain HB09003T and HB12160 are proposed to represent a novel species of the genus Gracilibacillus, for which the name Gracilibacillusmarinus sp. nov. is proposed. The type strain is HB09003T (=CGMCC 1.10343T = DSM 23372T).