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}ω7c/C_{16: 1}ω6c; 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).