Halomonas songnenensis sp. nov., a moderately halophilic bacterium isolated from saline and alkaline soils

Abstract

A moderately halophilic bacterium (strain NEAU-ST10-39T) was isolated from saline and alkaline soils in the oilfield of Daqing City, Heilongjiang Province, China. The strain was strictly aerobic, Gram-stain-negative, rod-shaped and motile by peritrichous flagella. Its colonies were yellow. It grew at NaCl concentrations of 0.2-15% (w/v) (optimum 4%, w/v), at temperatures of 4-40 °C (optimum 35 °C) and at pH 5-10 (optimum pH 7). It did not produce acids from sugars or alcohols. Its DNA G+C content was 57.4 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and concatenated 16S rRNA, gyrB and rpoD gene sequences indicated that it belonged to the genus Halomonas in the class Gammaproteobacteria. The most phylogenetically related species were Halomonas axialensis, Halomonas meridiana and Halomonas aquamarina, whose types shared 98.3% (16S rRNA), 82.7% (gyrB) and 83.9-84.5% (rpoD) sequence similarity with strain NEAU-ST10-39T. The results of DNA-DNA hybridization assays showed 20±2%-50±1 % relatedness between strain NEAU-ST10-39T and the most closely related species including Halomonas axialensis DSM 15723T, Halomonas meridiana DSM 5425T, Halomonas aquamarina DSM 30161(T), Halomonas johnsoniae DSM 21197T, Halomonas stevensii DSM 21198T, Halomonas nanhaiensis CCTCC AB 2012911(T), Halomonas hamiltonii DSM 21196T and Halomonas arcis CGMCC 1.6494T. The major fatty acids were C18 : 1ω7c (47.2%), C16:1ω7c and/or C16:1ω6c (18.9%) and C16:0 (16.3%), the only respiratory quinone detected was ubiquinone 9 and polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unknown phospholipids and three unknown lipids. The new isolate is proposed to represent a novel species with the name Halomonas songnenensis sp. nov., NEAU-ST10-39T (=CGMCC 1.12152T=DSM 25870T) being the type strain.