Nesterenkonia suensis sp. nov., a haloalkaliphilic actinobacterium isolated from a salt pan.

A Gram-positive, non-motile, non-spore-forming actinobacterium designated strain Sua-BAC020(T) was isolated from brine from Sua salt pan in Botswana. The strain was alkaliphilic and moderately halophilic, displaying optimal growth at 35-37 °C, pH 9 and 2.5 % (w/v) NaCl. Comparative 16S rRNA gene sequence analysis showed that strain Sua-BAC020(T) belonged to the genus Nesterenkonia, sharing 96.2-99.0 % sequence similarity with the type strains of recognized species within this genus. DNA-DNA hybridization with the type strains of species that showed the closest phylogenetic affiliation, Nesterenkonia xinjiangensis (16S rRNA gene sequence similarity, 98.9 %), Nesterenkonia aethiopica (99.0 %), Nesterenkonia halophila (97.5 %), Nesterenkonia flava (97.4 %) and Nesterenkonia halobia (97.2 %), gave relatedness values of 10-45 %. The peptidoglycan type of strain Sua-BAC020(T) was A4α, L-Lys-Gly-D-Asp. Cells of the isolate contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and unidentified glycolipids as major polar lipids, MK-8, MK-9 and MK-7 were the predominant menaquinones, and the major fatty acids (>10 %) were anteiso-C(15:0) and anteiso-C(17 : 0). The DNA G+C content of strain Sua-BAC020(T) was 64.8 mol%. Based on DNA-DNA hybridization, and physiological and biochemical tests, strain Sua-BAC020(T) is distinct from all recognized Nesterenkonia species, suggesting that this strain represents a novel species, for which the name Nesterenkonia suensis sp. nov. is proposed. The type strain is Sua-BAC020(T) (= DSM 22748(T)=NCCB 100309(T)).