Nesterenkonia natronophila sp. nov., an alkaliphilic actinobacterium isolated from a soda lake, and emended description of the genus Nesterenkonia.

A Gram-stain-positive, alkaliphilic, moderately halophilic, cocci-shaped actinobacterium (strain M8) was isolated from a sample of soda lake sediment (Lake Magadi, Tanzania). The isolate was heterotrophic, strictly aerobic, catalase-positive, oxidase-negative and formed orange-pigmented colonies in solid media. It utilized various sugars and organic acids as sole carbon sources. The organism grew at 10-38 °C, at pH 7.5-12.0 and in the presence of 1-12 % (w/v) NaCl, with optimal growth occurring at 30 °C, at pH 10 and in the presence of 5 % (w/v) NaCl. Comparative 16S rRNA gene sequence analysis showed that strain M8 belonged to the genus Nesterenkonia, sharing the closest similarities to Nesterenkoniahalobia DSM 20541, Nesterenkoniahalophila YIM 70179 and Nesterenkoniaaethiopica DSM 17733 (97.5, 97.5 and 97.1 %, respectively). The characteristic diamino acid of strain M8 was found to be lysine and the polar lipids detected were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unidentified glycolipids and two unidentified phospholipids. The DNA G+C content was 61.8 mol% (genome). The strain contained MK-7, MK-9 and MK-10 as the respiratory quinones, and the major fatty acids (>10 %) comprised anteiso-C17 : 0 and anteiso-C15 : 0. On the basis of phylogenetic analyses and phenotypic data, strain M8 is considered to represent a novel species, for which the name Nesterenkonianatronophila sp. nov. is proposed. The type strain is M8 (=JCM 32100=CGMCC 1.16706=MCC 3367).