Alkaliphilus halophilus sp. nov., a strictly anaerobic and halophilic bacterium isolated from a saline lake, and emended description of the genus Alkaliphilus.

A novel strictly anaerobic, halophilic and fermentative strain, designated E2R(T), was isolated from sediments of Xiaokule salt lake in Xinjiang Province, China. Cells were straight to slightly curved, Gram-stain-positive rods that were motile by means of flagella and formed endospores. Strain E2R(T) was moderately halophilic and grew optimally in the presence of 7.5 % NaCl, at pH 8.0 and at 32°C. Substrates used include yeast extract, Casamino acids, tryptone, fructose, sucrose, xylose, ribose, lactate and tartrate. Thiosulfate could be used as an accessory electron acceptor and stimulated growth. The main fermentation products from fructose were formate and acetate. The predominant fatty acids were iso-C(15 : 0), iso-C(15 : 1) F and iso-C(13 : 0). 16S rRNA gene sequence analyses revealed that strain E2R(T) was related most closely to members of the genus Alkaliphilus (95.5-91.1 % similarity). The G+C content of strain E2R(T) was 28.5 mol%. Strain E2R(T) could be differentiated from its closest relatives based on its halophilic nature and its lower DNA G+C content. It could also be differentiated based on its substrate utilization pattern and relatively high levels of iso-C(15 : 0). On the basis of these data, strain E2R(T) is considered to represent a novel species of the genus Alkaliphilus, for which the name Alkaliphilus halophilus sp. nov. is proposed. The type strain is E2R(T) (=CGMCC 1.5124(T) =JCM 16124(T)). An emended description of the genus Alkaliphilus is also provided.