Hymenobacter aquaticus sp nov., a radiation-resistant bacterium isolated from a river

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterial strain, designated 16F3P(T), was isolated from the Han River, South Korea, and characterized taxonomically using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed 16F3P(T) to be within the genus Hymenobacter, and most closely related to Hymenobacter chitinivorans Txc1(T) (98.62 %) and Hymenobacter elongatus VUG-A112(T) (98.46 %). The phylogenetic distance from other species of the genus Hymenobacter with validly published names was greater than 4% (i.e. sequence similarity was less than 96.0 %). Chemotaxonomic data also supported the classification of strain 16F3P(T) within the genus Hymenobacter. C-16:0 (19.8 %), summed feature 3( C-16:1 omega 7c/C-16:1 omega 6c; 15.4 %) and iso-C-15:0 (13.0 %) were the major fatty acids, MK-7 was the predominant respiratory quinone, and phosphatidylethanolamine was the major polar lipid. The G+C content of the genomic DNA of strain 16F3P(T) was 61.9 mol%. DNA-DNA hybridization experiments showed that the values for DNA-DNA relatedness between strain 16F3P(T) and the phylogenetically closest neighbours were below 19 %. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain 16F3P(T) represents a novel species of the genus Hymenobacter, for which the name Hymenobacter aquaticus sp. nov. is proposed. The type strain is 16F3P(T) (= KCTC 52194(T) = JCM 31653(T)).