Gracilibacillus kekensis sp. nov., a moderate halophile isolated from Keke Salt Lake

Abstract

A novel moderately halophilic bacterium, designated strain K170T, was isolated from Keke Salt Lake in Qinghai, China. The strain grew with 0–22 % (w/v) NaCl, at 4–50 °C and at pH 6–11, with optimum growth in 3 % (w/v) NaCl, at 40 °C and at pH 8. The predominant respiratory quinone was menaquinone 7 (MK-7). The polar lipids included diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids, aminolipids and glycolipids. The major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 0. The DNA G+C content was 35.8 mol%. Phylogenetic analysis based on the full-length 16S rRNA gene sequence revealed that strain K170T was a member of the genus Gracilibacillus . High levels of 16S rRNA gene sequence similarity were found between strain K170T and Gracilibacillus boraciitolerans DSM 17256T (97.3 %) and Gracilibacillus thailandensis JCM 15569T (97.1 %). 16S rRNA gene sequence similarities between strain K170T and the type strains of other recognized members of the genus Gracilibacillus were below 97 %. The DNA–DNA hybridization values of strain K170T with G. boraciitolerans DSM 17256T and G. thailandensis JCM 15569T were 21.9 % and 34.3 %, respectively. On the basis of these results, strain K170T is considered to represent a novel species of the genus Gracilibacillus , for which the name Gracilibacillus kekensis sp. nov. is proposed; the type strain is K170T ( = CGMCC 1.10681T = DSM 23178T).