Bacillus natronophilus sp. nov., an alkaliphilic bacterium isolated from a soda lake

An alkaliphilic, moderately halophilic, heterotrophic, rod-shaped, spore-forming bacterium (M30(T)) was isolated from a sediment sample collected from a soda lake (Lake Magadi, Tanzania). Strain M30(T) was strictly aerobic, catalase-positive, oxidase-negative and non-motile. Growth occurred at 12-43 degrees C (optimum, 25-30 degrees C), at pH 8.0-12 (optimum, pH 9.5-10) and at salinities of 0.5-15% (w/v) NaCl (optimum 5%). It utilized various sugars and organic acids as sole carbon sources and was positive for amylase, cellulase, gelatinase, protease and xylanase activities. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified lipid and one unidentified phospholipid. The DNA G+C content was 48.9 mol%. The predominant menaquinone was MK-7 and the major fatty acids (>10%) comprised anteiso-C-15:0, iso-C-15:0, and anteiso-C-17:0. Phylogenetic analysis based on 16S rRNA gene sequence affiliated M30(T) to the genus Bacillus and showed the highest similarities to Bacillus populi FJAT-45347(T) (96.4%) and Bacillus aurantiacus K1-5(T) (96.2%). Based on the data from the current polyphasic study, M30(T) represents a novel species of the genus Bacillus, for which the name Bacillus natronophilus sp. nov. is proposed. The type strain is M30(T) (=JCM 32118(T)=CGMCC 1.16739(T)=MCC 3010(T)).