Haloterrigena longa sp. nov. and Haloterrigena limicola sp. nov., extremely halophilic archaea isolated from a salt lake

Abstract

Halophilic archaeal strains ABH32T and AX-7T were isolated from Aibi salt lake in Xin-Jiang, China, and were subjected to taxonomic studies. The cells of both strains were rod-shaped, and growth required at least 10 % (w/v) NaCl. The cellular polar lipids were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and mannose-2,6-disulfate (1→2)-glucose glycerol diether (S2-DGD). The isolates were different in that strain ABH32T did not require magnesium and had strong ability to assimilate sugars for growth, whereas strain AX-7T required magnesium and did not assimilate glucose, sucrose or maltose for growth. Both strain ABH32T and strain AX-7T were most closely related to members of the genera Haloterrigena and Natrinema. On the basis of phenotypic and genotypic characteristics, especially their cellular polar lipids, the two isolates were assigned to the genus Haloterrigena. Moreover, the DNA relatedness values for strains ABH32T and AX-7T with respect to members of the genus Haloterrigena were found to be well below 70 %. Thus, strains ABH32T and AX-7T represent two novel species within the genus Haloterrigena, for which the names Haloterrigena longa sp. nov. (type strain ABH32T=CGMCC 1.5334T=JCM 13562T) and Haloterrigena limicola sp. nov. (type strain AX-7T=CGMCC 1.5333T=JCM 13563T) are proposed.