Abstract
An aerobic and heterotrophic isolate, designated IFAM EL-30(T), was obtained from hypersaline Ekho Lake (Vestfold Hills, East Antarctica). The isolate consisted of Gram-positive cocci or short rods which occasionally exhibited branching. The organism was moderately halotolerant, required thiamin.HCl and was stimulated by biotin and nicotinic acid. It grew well with glucose, acetate, pyruvate, succinate, malate or glutamate, and hydrolysed DNA but not gelatin, starch or Tween 80. Nitrate was aerobically reduced to nitrite. Chemical analysis revealed diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and an unidentified glycolipid as the major polar lipids. The cellular fatty acids were predominantly of the anteiso and iso methyl-branched types, and the major menaquinones were MK-7 and MK-8. The peptidoglycan type was A4alpha, L-Lys-L-Glu. The DNA base ratio was 66.1 mol% G+C. Comparisons of 16S rRNA gene sequences showed that the unidentified organism was phylogenetically closely related to Nesterenkonia halobia, although a sequence divergence value of >3% demonstrated that the organism represents a different species. On the basis of phenotypic and genotypic evidence, it is proposed that the unknown bacterium be designated as a new species of the genus Nesterenkonia, namely Nesterenkonia lacusekhoensis sp. nov., the type strain being IFAM EL-30(T) (=DSM 12544(T)=CIP 107030(T)). An emended description of the genus Nesterenkonia is given.