Ramlibacter algicola sp. Nov., isolated from a freshwater alga cryptomonas obovoidea

Abstract

A Gram-stain-negative, strictly aerobic, catalase-negative, oxidase-positive and non-motile rod-shaped bacterium, designated strain CrO1T, was isolated from a freshwater alga Cryptomonas obovoidea in the Nakdong river of South Korea. Colonies of CrO1T were white, convex and circular and growth was observed at 25–40 °C (optimum, 37 °C) and pH 6.0–9.0 (optimum, pH 7) and in the presence of 0–0.5% (w/v) NaCl (optimum, 0%). CrO1T contained C16:0, summed feature 5 (comprising C18:0 ante and/ or C18:2 ω6,9c), C18:0, summed feature 3 (comprising C16:1 ω7c and/or C16:1 ω6c) and summed feature 8 (comprising C18:1 ω7c and/ or C18:1 ω6c) as the major cellular fatty acids (>5%) and ubiquinone-8 as the sole respiratory quinone. Phosphatidylethanola-mine was detected as the major polar lipid. The DNA G+C content of CrO1T, calculated from the whole genome sequence was 69.6 mol%. CrO1T was most closely related to Ramlibacter humi 18x22-1T with a 97.6% 16S rRNA sequence similarity and shared less than 97.4% 16S rRNA sequence similarities with other type strains. Phylogenetic analyses based on the 16S rRNA gene and whole genome sequences revealed that CrO1T formed a distinct phyletic lineage within the genus Ramlibacter. On the basis of the results of phenotypic, chemotaxonomic and molecular analysis, CrO1T clearly represents a novel species of the genus Ramlibacter, for which the name Ramlibacter algicola sp. nov. is proposed. The type strain is CrO1T (=KACC 19926T=JCM 33302T). © 2021 The Authors.