Natrialba swarupiae sp. nov., a halophilic archaeon isolated from a hypersaline lake in India

A haloarchaeal strain (ESP3B_9(T)) was isolated from the salt pan of Sambhar salt lake, Rajasthan, India. Cells were coccoid, non-motile, Gram-stain-negative and formed reddish-pink pigmented colonies. The strain was aerobic, able to grow at 35-55 degrees C (optimum, 40 degrees C), in 20-35% (25%) NaCl and pH 8-10 (pH 9). Mg2+ not required for growth. The cells were lysed in distilled water and the minimum NaCl concentration that prevented cell lysis was 5% w/v. The 165 rRNA gene sequence similarities between strain ESP3B_9(T) and Natrialba hulunbeirensis JCM 10989(T) and Natrialba magadii ATCC 43099(T) were 96.53 and 96.25 % respectively. The similarities of the RNA polymerase subunit B gene between strain ESP3B_9(T) and N. hulunbeirensis JCM 10989(T) and N. magadii ATCC 43099(T) were 84.47 and 84.9 % respectively. Genome sequencing revealed a genome size of 4.20 Mbp with DNA G+C content of 62.5 mol%. The major polar lipids were phosphotidylglycerol and phosphatidylglycerol phosphate methyl esters with minor amounts of unidentified lipids. The results of polyphasic analysis determined that strain ESP3B_9(T) represents a novel species of the genus Natrialba, for which the name Natrialba swarupiae sp. nov. is proposed. The type strain is ESP3I3_9(T) (MCC 3419(T )=JCM 33002(T) =KCTC 4279(T) =CGMCC 1.16737(T)).