Characterization of Deinococcus sahariens sp. nov., a radiation-resistant bacterium isolated from a Saharan hot spring
ABSTRACT An ultraviolet-radiation-resistant, Gram-positive, orange-pigmented, thermophilic and strictly aerobic cocci was isolated
from Saharan water hot spring in Tunisia. The newly isolated bacterium, designated HAN-23T, was identified based on polyphasic taxonomy including genotypic, phenotypic and chemotaxonomic characterization. Phylogenetic
analysis based on 16S rRNA gene sequences placed this strain within Deinococcus genus. However, strain HAN-23T is different from recognized species of the genus Deinococcus, showing less than 94.0% similarity values to its closest relatives. The predominant cellular fatty acids determined by gas
chromatography were iso-C15:0, iso-C17:0 and iso C17:1 ω9c. The major respiratory quinone was MK-8. The DNA G+C content was 66.9mol%. DNA–DNA hybridization measurements revealed
low DNA relatedness (6%) between the novel isolate and its closest neighbor, the type strain Deinococcus geothermalis DSM 11300. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain HAN-23T represents a novel species of the genus Deinococcus, for which the name Deinococcus sahariens sp. nov. is proposed, the type strain being HAN-23T (=DSM 18496T; LMG 23756T).
KeywordsTaxonomy–New species–Sahara–Hot spring–Deinococcus–UV resistance