Abstract

Strain 16F1ET was isolated from a 3-kGy-irradiated sediment sample collected at Han River in Seoul, Republic of Korea. Cells of this strain were observed to be Gram-positive, pililike structure, and short rod shape, and colonies were red in color. The strain showed the highest degree of 16S rRNA gene sequence similarity to Deinococcus aquaticus PB314T (98.8%), Deinococcus depolymerans TDMA-24T (98.1%), Deinococcus caeni Ho-08T (98.0%), and Deinococcus grandis DSM 3963T (97.0%). 16S rRNA gene sequence analysis identified this strain as a member of the genus Deinococcus (Family: Deinococcaceae). The genomic DNA G+C content of strain 16F1ET was 66.9 mol%. The low levels of DNA-DNA hybridization (< 56.2%) with the species mentioned above identified strain 16F1ET as a novel Deinococcus species. Its oxidase and catalase activities as well as the production of acid from glucose were positive. Growth of the strain was observed at 10–37°C (optimum: 20–30°C) and pH 4–10 (optimum: pH 7–8). The cells tolerated less than 5% NaCl and had low resistance to gamma radiation (D10 < 4 kGy). Strain 16F1ET possessed the following chemotaxonomic characteristics: C16:0, C15:1 ω6c, and C16:1 ω7c as the major fatty acids; phosphoglycolipid as the predominant polar lipid; and menaquinone-8 as the predominant respiratory isoprenoid quinone. Based on the polyphasic evidence, as well as the phylogenetic, genotypic, phenotypic, and chemotaxonomic characterization results, strain 16F1ET (=KCTC 33793T =JCM 31404T) is proposed to represent the type strain of a novel species, Deinococcus seoulensis sp. nov.

• Keywords: Deinococcus; polyphasic taxonomy; gamma-radiation resistance