Halomonas nanhaiensis sp. nov., a halophilic bacterium isolated from a sediment sample from the South China Sea

Abstract

A novel Gram-negative, aerobic, slightly halophilic, yellow-pigmented, oxidase-negative, Voges-Proskauer positive, non-spore-forming bacterium, designated YIM M 13059(T), was isolated from a sediment sample collected from the South China Sea at a depth of 310 m. Optimal growth was found to occur at 28-30 °C, pH 7.0 and in the presence of 3-4 % (w/v) NaCl. Cells were observed to be rod-shaped and motile by peritrichous flagella. The polar lipids of strain YIM M 13059(T) were found to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, a ninhydrin-positive phospholipid, one glycolipid and two unknown phospholipids. The predominant respiratory quinone was determined to be Q-9. The major fatty acids were identified as C18:1 ω7c, C16:1 ω6c/C16:1 ω7c, C16:0 and C12:0 3-OH. The genomic DNA G+C content was determined to be 54.4 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the isolate belongs to the genus Halomonas in the family Halomonadaceae. The 16S rRNA gene sequence similarities between strain YIM M 13059 (T) and the type strains of members of the genus Halomonas were in the range 93.3-98.3 %. However, the levels of DNA-DNA relatedness values between YIM M 13059 and the type strains of the most closely related species, Halomonas zhangjiangensis, Halomonas variabilis, Halomonas neptunia, Halomonas boliviensis and Halomonas sulfadieris were 50.2 ± 0.68 %, 46.8 ± 1.9 %, 28.5 ± 0.74 %, 42.9 ± 0.55 % and 37.1 ± 0.68 %, respectively. Based on phylogenetic, chemotaxonomic and phenotypic data, the strain YIM M 13059(T) is proposed to represent a novel member of the genus Halomonas, with the name Halomonas nanhaiensis sp. nov. The type strain is YIM M 13059(T) (=JCM 18142(T) =CCTCC AB 2012911(T)).