A novel bacterium, designated R14M6T, was isolated from deep-sea sediment collected from the Ross Sea, Antarctica. Cells are Gram-stain-negative, aerobic, pale yellow, short-rod-shaped, polar-flagellated and aggregate-forming. Growth occurs at 4-36 °C, pH 6.0-8.3, and in 1-15 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain R14M6T clustered together with Aurantimonas endophytica EGI6500337T and fell within the genus Aurantimonas. The 16S rRNA gene sequence of strain R14M6T shared similarity with A. endophytica EGI6500337T (99.15 %), A. manganoxydans DSM 21871T (97.73 %), A. coralicida DSM 14790T (97.58 %) and 'A. litoralis' KCTC 12094 (97.51 %). The DNA-DNA relatedness values between strain R14M6T and A. endophytica EGI6500337T, A. coralicida DSM 14790T, A. manganoxydans DSM 21871T and 'A. litoralis' KCTC 12094 were 36.9±4.5, 27.6±2.8, 29.6±1.2 and 25.2±2.4 % respectively. The major fatty acid of strain R14M6T was C18 : 1ω7c. The major polar lipids were phosphatidylcholine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminolipid. Strain R14M6T contained Q-10 as the dominant isoprenoid quinone. The DNA G+C content of strain R14M6T was 67.4 mol%. Based on the phylogenetic, physiological and chemotaxonomic analyses, strain R14M6T represents a novel species of the genus Aurantimonas, for which the name Aurantimonas aggregata sp. nov. is proposed. The type strain is R14M6T (=GDMCC 1.1202T=KCTC 52919T).
Keywords: Antarctica; Aurantimonadaceae; Aurantimonas; Ross Sea; marine sediment; polyphasic taxonomy.