Halomonas ramblicola sp. nov., a moderately halophilic bacterium from Rambla Salada, a Mediterranean hypersaline rambla

Abstract

A moderately halophilic bacterium (strain RS-16(T)) was isolated from saline soil in Rambla Salada, a Mediterranean hypersaline rambla in Murcia, south-east Spain. Cells of strain RS-16(T) were Gram-negative rods, oxidase-negative and motile by peritrichous flagella. Strain RS-16(T) required NaCl for growth, and grew between 1% and 30% (w/v) NaCl (optimum, 5-7.5%), at temperatures of between 4 °C and 41 °C (optimum, 32-37 °C), and at pH values of between 5 and 10 (optimum, pH 7). Strain RS-16(T) was chemo-organotrophic and its metabolism was respiratory with oxygen and nitrate as terminal electron acceptors. It produced acids from d-glucose and myo-inositol, accumulated poly-β-hydroxyalkanoate granules and produced cream colonies on MY 7.5% (w/v). The DNA G+C content of strain RS-16(T) was 56.2 mol%. A comparison of 16S rRNA gene sequences confirmed the relationship of strain RS-16(T) to species of the genus Halomonas. The most phylogenetically related species was Halomonas cerina SP4(T) (97.4%16S rRNA gene sequence similarity). In DNA-DNA hybridization assays strain RS-16(T) showed DNA-DNA relatedness values of 62.7 ± 3.09%, 64.5 ± 1.97% and 64.7 ± 1.74% to Halomonas cerina CECT 7282(T), Halomonas cerina CECT 7284 and Halomonas cerina CECT 7283, respectively. The major fatty acids of strain RS-16(T) were C(18:1)ω7c and C(16:0), and the predominant respiratory lipoquinone was ubiquinone, with nine isoprene units (Q-9). On the basis of these data, strain RS-16(T) is considered to represent a novel species of the genus Halomonas, for which the name Halomonas ramblicola sp. nov. is proposed. The type strain is RS-16(T) ( = CECT 7896(T) = LMG 26647(T)).