Int J Syst Evol Microbiol. (2019) 69: 732-738

Haloarcula sebkhae sp. nov., an extremely halophilic archaeon from Algerian hypersaline environment

Barreteau, H.; Vandervennet, M.; Guédon, L.; Point, V.; Canaan, S.; Rebuffat, S.; Peduzzi, J.; Carré-Mlouka, A.

One halophilic organism, SWO25 was isolated from salted water sampled in Algeria in the salt lake (sebkha) of Ouargla. The novel strain stained Gram-negative, and cells were pleomorphic with a red pigmentation. Strain SWO25 grew optimally at 35-45°C, at pH 6.0-8.0 and 0.05-0.25 M MgCl2 concentrations. Cells were extremely halophilic, with an optimal growth at 4.3-5.1 M NaCl. The predominant membrane polar lipids were C20C20 glycerol diether derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate, phosphatidylglycerol sulfate, and triglycosyl diether and diglycosyl diether. The major respiratory menaquinone component was MK-8. Cells were highly tolerant to the presence of decane and isooctane in the growth medium. Chemotaxonomic properties supported the assignment of strain SWO25 to the genus Haloarcula. The DNA G+C content was 61.1 mol%. DNA-DNA hybridization and phylogenetic analyses of the 16S rRNA and rpoB’ genes showed that strain SWO25 is distinct from known Haloarcula species. Based on phenotypic, chemotaxonomic, genotypic and phylogenetic data, we describe a novel species of the genus Haloarcula for which the name Haloarcula sebkhae sp. nov. is proposed. The type strain is SWO25T (=CIP 110583T=JCM 19018T).