Methylophaga alcalica sp nov., a novel alkaliphilic and moderately halophilic, obligately methylotrophic bacterium from an East Mongolian saline soda lake

A moderately haloalkaliphilic and obligately methylotrophic bacterium (strain M39(T)) with the ribulose monophosphate pathway of carbon assimilation is described. Cells of this methanol and methylamine utilizer are aerobic, Gram-negative, asporogenous, motile short rods, multiplying by binary fission. It is auxotrophic for vitamin B-12 and requires NaHCO3 or NaCl for growth in alkaline medium. Its cellular fatty acid profile consists primarily of straight-chain saturated C-16:0 and unsaturated C-16:1 and C-18:1 acids. The major ubiquinone is O-8. The dominant phospholipids are phosphatidylethanolamine and phosphatidylglycerol. Diphosphatidylglycerol is also present. Optimal growth conditions are 25-29 degreesC, pH 9.0-9.5 and 3-4 % (w/v) NaCl. Cells accumulate the cyclic amino acid ectoine as the main compatible solute. The DNA G + C content is 48.3 mol%. Based on 16S rDNA sequence analysis and DNA-DNA relatedness (25-30%) with the type strains of marine methylotrophs belonging to the genus Methylophaga, the novel isolate M39(T) (=VKM B-2251(T) =ATCC BAA-297(T)) was classified as the type strain of Methylophaga alcalica sp. nov.