Strain 16F3HT, a Gram-negative, aerobic, non-motile, and oval-shaped bacterium, was isolated from river water collected from the Han River in South Korea. Growth of strain 16F3HT was observed at 10-42 °C (optimum at 25-30 °C), but no growth occurred at 4 °C. The strain is able to grow at pH 4-10 (optimum at pH 7-8) and tolerates up to 4% NaCl (w/v), with optimum growth at 0.5% NaCl. The isolate was found to be resistant to UV irradiation. Based on 16S rRNA gene sequence analysis, it is closely related to 'Deinococcus seoulensis' 16F1E (98.8%), Deinococcus aquaticus PB314T (98.1%) and Deinococcus caeni Ho-08T (98.0%). The level of DNA-DNA homology between the novel strain and the three related strains was 57.4, 41.2, and 35.8%, respectively. Chemotaxonomic data revealed that strain 16F3HT possesses MK-8 as the predominant respiratory quinone, an unidentified phosphoglycolipid as the major polar lipid, and C15:1 ω6c and C16:1 ω7c as the major fatty acids. The DNA G + C content was determined to be 65.7 mol%. Based on polyphasic evidence, strain 16F3HT (=KCTC 33794T = JCM 31406T) should be classified as the type strain of a novel Deinococcus species, for which the name Deinococcus knuensis sp. nov. is proposed.
Keywords: 16S rRNA gene; Deinococcus; Polyphasic taxonomy; River water; UV resistance.