Haloferax sulfurifontis sp. nov., a halophilic archaeon isolated from a sulfide- and sulfur-rich spring

Abstract

A pleomorphic, extremely halophilic archaeon (strain M6T) was isolated from a sulfide- and sulfur-rich spring in south-western Oklahoma (USA). It formed small (0·8–1·0 mm), salmon pink, elevated colonies on agar medium. The strain grew in a wide range of NaCl concentrations (6 % to saturation) and required at least 1 mM Mg2+ for growth. Strain M6T was able to reduce sulfur to sulfide anaerobically. 16S rRNA gene sequence analysis indicated that strain M6T belongs to the family Halobacteriaceae, genus Haloferax; it showed 96·7–98·0 % similarity to other members of the genus with validly published names and 89 % similarity to Halogeometricum borinquense, its closest relative outside the genus Haloferax. Polar lipid analysis and DNA G+C content further supported placement of strain M6T in the genus Haloferax. DNA–DNA hybridization values, as well as biochemical and physiological characterization, allowed strain M6T to be differentiated from other members of the genus Haloferax. A novel species, Haloferax sulfurifontis sp. nov., is therefore proposed to accommodate the strain. The type strain is M6T (=JCM 12327T=CCM 7217T=DSM 16227T=CIP 108334T).