Mongoliibacter ruber gen. nov., sp. nov., a haloalkalitolerant bacterium of the family Cyclobacteriaceae isolated from a haloalkaline lake.

Abstract

A novel haloalkalitolerant, rod-shaped bacterium, designated strain YIM 4-4T, was isolated from the surface water of the Dugerno lake, a haloalkaline lake in Inner Mongolia. The taxonomy of strain YIM 4-4T was investigated by a polyphasic approach. Strain YIM 4-4T was Gram-stain-negative, strictly aerobic, non-motile and formed red colonies. Optimal growth conditions were 28 °C, pH 8.0-11.0 and 0.5-2 % NaCl. The major respiratory quinone was menaquinone-7 (MK-7). The polar lipid profile was composed predominantly of phosphatidylethanolamine, six unidentified polar lipids, one phospholipid and one aminolipid. The predominant cellular fatty acids (>5 %) were iso-C15 : 0, iso-C17 : 1I/anteiso-C17 : 1B, iso-C16 : 1G, iso-C17 : 0 3-OH, C16 : 1ω7c/C16 : 1ω6c and iso-C16 : 1. The genomic DNA G+C content was 43.0 mol%. 16S rRNA gene sequence analysis indicated that the members of the genera Cecembia, Fontibacter, Aquiflexum and Indibacter of the family Cyclobacteriaceae (phylum Bacteroidetes) were the most closely related, with 16S rRNA gene sequence similarities ranging from 93.6 to 94.2 %. Other members of the family Cyclobacteriaceae showed sequence similarities < 93.0 %. On the basis of phenotypic, chemotaxonomic and phylogenetic properties, strain YIM 4-4T represents a novel species of a new genus, for which the name Mongoliibacter ruber gen. nov., sp. nov. is proposed. The type strain is YIM 4-4T ( = CCTCC AB 2012966T = DSM 27929T).