A gamma radiation-resistant, Gram-stain-negative, rod-shaped bacterial strain, designated SJW1-2T, was isolated from freshwater samples collected from the Seomjin River, Republic of Korea. The 16S rRNA gene sequence analyses showed that strain SJW1-2T was most closely related to Deinococcus metalli 1PNM-19T (94.3 % sequence similarity) and formed a robust phylogenetic clade with other species of the genus Deinococcus. The optimum growth pH and temperature for the isolate were pH 7.0-7.5 and 25 °C, respectively. Strain SJW1-2T exhibited high resistance to gamma radiation. The predominant respiratory quinone was MK-8. The polar lipid profile consisted of different unidentified glycolipids, two unidentified lipids, two unidentified phospholipids and an unidentified phosphoglycolipid. The major peptidoglycan amino acids were alanine, d-glutamic acid, glycine and l-ornithine. The predominant fatty acids (>10 %) were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) (25.2 %) and C16 : 0 (21.2 %), and the DNA G+C content was 69.5 mol%. On the basis of phenotypic, genotypic and phylogenetic analyses, strain SJW1-2T (=KACC 19332T=NBRC 112908T) represents a novel species of the genus Deinococcus, for which the name Deinococcus koreensis sp. nov. is proposed.
Keywords: Deinococcus; Deinococcus koreensis; polyphasic taxonomy; radiation-resistant.