Methylophaga lonarensis sp. nov., a moderately haloalkaliphilic methylotroph isolated from the soda lake sediments of a meteorite impact crater

A moderately haloalkaliphilic methylotrophic bacterium possessing the ribulose monophosphate pathway for carbon assimilation, designated MPL^T, was isolated from Lonar Lake sediment microcosms that were oxidizing methane for two weeks. The isolate utilized methanol and was an aerobic, Gram-negative, asporogenous, motile, short rod that multiplied by binary fission. The isolate required NaHCO₃ or NaCl for growth and, although not auxotrophic for vitamin B₁₂, had enhanced growth with vitamin B₁₂. Optimal growth occurred with 0.5-2% (w/v) NaCl, at 28- 30 °C and at pH 9.0-10.0. The cellular fatty acid profile consisted primarily of straight-chain saturated C_{16: 0} and unsaturated C_{16: 1}ω7c and C_{18: 1}ω7c. The major ubiquinone was Q-8. The dominant phospholipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Cells accumulated ectoine as the main compatible solute. The DNA G+C content was 50.0 mol%. The isolate exhibited 94.0-95.4% 16S rRNA gene sequence similarity with the type strains of methylotrophs belonging to the genus Methylophaga and 31% DNA-DNA relatedness with the reference strain, Methylophaga alcalica VKM B-2251^T. It is proposed that strain MPL^T represents a novel species, Methylophaga lonarensis sp. nov. (type strain MPL^T=VKM B-2684^T=MCC 1002^T).