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 T ) 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 T belonged to the genus Nesterenkonia, sharing the closest similarities to Nesterenkoniahalobia DSM 20541 T , Nesterenkoniahalophila YIM 70179 T and Nesterenkoniaaethiopica DSM 17733 T (97.5, 97.5 and 97.1 %, respectively). The characteristic diamino acid of strain M8 T 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 T is considered to represent a novel species, for which the name Nesterenkonianatronophila sp. nov. is proposed. The type strain is M8 T (=JCM 32100 T =CGMCC 1.16706 T =MCC 3367 T ).