Gracilimonas sediminicola sp. nov., a moderately halotolerant bacterium isolated from seaweed sediment collected in the East Sea, Republic of Korea

Abstract

A Gram-stain-negative, aerobic, rod-shaped bacterium, designated as strain CAU 1638T, was isolated from seaweed sediment collected in the Republic of Korea. The cells of strain CAU 1638T grew at 25-37 °C (optimum, 30 °C), at pH 6.0-7.0 (optimum, pH 6.5) and in the presence of 0-10% NaCl (optimum, 2 %). The cells were positive for catalase and oxidase and did not hydrolyse starch and casein. Strain CAU 1638T was most closely related to Gracilimonas amylolytica KCTC 52885T (97.7 %), followed by Gracilimonas halophila KCTC 52042T (97.4 %), Gracilimonas rosea KCCM 90206T (97.2 %), Gracilimonas tropica KCCM 90063T and Gracilimonas mengyeensis DSM 21985T (97.1 %), as revealed by 16S rRNA gene sequencing. MK-7 was the major isoprenoid quinone, and iso-C15 : 0 and C15 : 1 ω6c were the major fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, two unidentified lipids, two unidentified glycolipids and three unidentified phospholipids. The G+C content of the genome was 44.2 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain CAU 1638T and the reference strains were 73.1-73.9 % and 18.9-21.5 %, respectively. Based on its phylogenetic, phenotypic and chemotaxonomic features, strain CAU 1638T represents a novel species of the genus Gracilimonas, for which the name Gracilimonas sediminicola sp. nov. is proposed. The type strain is CAU 1638T (=KCTC 82454T=MCCC 1K06087T).