Salipaludibacillus daqingensis sp. nov., a moderately halophilic bacterium isolated from an oilfield

Abstract

A novel alkaliphilic, Gram-stain-positive, moderately halophilic, rod-shaped, endospore-forming, motile, facultatively anaerobic bacterium (DQ-9T) was isolated from a sediment sample collected from Daqing oilfield in China, and characterized by a polyphasic taxonomic approach. Strain DQ-9T formed yellow pigment and grew occurred at salinities of 1–12 % (w/v) NaCl (optimum, 8 %) and at 10–40 °C (optimum, 30–35 °C), at pH 7.5–10.5 (optimum, pH 9.0–9.5). It was catalase-positive, but oxidase-negative. Based on the analysis of 16S rRNA gene sequences, DQ-9T was classified into the genus Salipaludibacillus and exhibited the highest similarities (98.37 %) to Salipaludibacillus neizhouensis JSM 071004T. Digital DNA–DNA hybridization and average nucleotide identity values between strain DQ-9T and the most closely related strain, S. neizhouensis DSM 19794T, were determined to be 72.0 and 21.6 %, respectively. The polar lipids were constituted by diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids (>5 %) comprised anteiso-C15: 0, anteiso-C17: 0, iso-C17: 0, iso-C15: 0 and C16: 0 . The cell-wall peptidoglycan contained meso-diaminopimelic acid, and menaquinone-7 was identified as the primary respiratory quinone. The DNA G+C content was 37.5 mol%. Through chemotaxonomic, physiological, and biochemical characterization, strain DQ-9T could be clearly distinguished from the closest Salipaludibacillus species. Based on provided data, strain DQ-9T is proposed to represent a novel species, Salipaludibacillus daqingensis sp. nov., within the genus Salipaludibacillus. The type strain is DQ-9T (=ACCC 60415T=KCTC 33936T).