Spirosoma fluminis sp. nov., a Gamma–Radiation Resistant Bacterium Isolated from Sediment of the Han River in South Korea

Abstract

A Gram-negative, long rod-shaped, and yellowish bacterium, designated as strain 15J17T^T, was isolated from sediment of the Han River in South Korea after exposure to 3 kGy of gamma radiation. The strain was catalase- and oxidase-positive and showed resistance to gamma radiation—D₁₀ value (i.e., the dose required to reduce the bacterial population by 10-fold) of >4 kGy. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the strain belonged to the genus Spirosoma and showed moderate degrees of sequence similarity with related species (90.6–93.5 %). Chemotaxonomic data revealed that the strain contained summed feature 3 (C_16:1ω7c/C_16:1ω6c), C_16:1ω5c, C_16:0, C_18:0, and C_15:0 iso as the major fatty acids; phosphatidylethanolamine, an unidentified aminophospholipid, and an unidentified polar lipid as the major polar lipids; and menaquinone-7 (MK-7) as the major quinone. The genomic DNA G+C content of the new strain was 48.3 mol%. Based on these data, type strain 15J17T^T (=KCTC 52198^T = JCM 31409^T) should be classified as representing a new species, for which we propose the name Spirosoma fluminis sp. nov.

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