Marivirga aurantiaca sp. nov., a halophilic nitrite-reducing bacterium, isolated from intertidal surface sediments

A novel Gram-stain-negative strain, designated S37H4^T, was isolated from an intertidal surface sediment sample collected from Zhanjiang City, Guangdong province, south PR China. Cells of the strain were aerobic, non-flagellated, long rod-shaped and motile by gliding. S37H4^T could grow at 4-40 °C, pH 7.0-8.5 and in 2.0-15.0 % NaCl, with optimal growth at 25-30 °C, pH 7.5 and 9.0 % NaCl, respectively. S37H4^T was capable of nitrite removal under high-salt conditions, and there were three denitrification genes, nirK, norB and nosZ, in its genome. The results of phylogenetic analyses based on the 16S rRNA gene and genome sequences indicated that S37H4^T represented a member of the genus Marivirga and formed a subclade with Marivirga lumbricoides JLT2000^T. S37H4^T showed the highest 16S rRNA sequence similarity to M. lumbricoides JLT2000^T (98.3 %) and less than 97.0 % similarity with other type strains of species of the genus Marivirga. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between S37H4^T and the reference type strains of species of the genus Marivirga were 70.7-74.3 % and 18.2-19.2 %, respectively. The major fatty acids of S37H4^T were iso-C_15 : 0, iso-C_15 : 1G, iso-C_17 : 0 3-OH and summed feature 3 (C_16 : 1ω6c and/or C_16 : 1ω7c). The major respiratory quinone of this novel strain was MK-7, and the predominant polar lipids were identified as phosphatidylethanolamine, an unidentified aminolipid, an unidentified phospholipid and three unidentified lipids. The results of analyses of phylogenetic, genomic, physiological and biochemical characteristics indicated that S37H4^T represented a novel species of the genus Marivirga, for which the name Marivirga aurantiaca sp. nov. is proposed. The type strain is S37H4^T (= GDMCC 1.1866^T = KACC 21922^T).