Bacillus caseinilyticus sp. nov., an alkali- and thermotolerant bacterium isolated from a soda lake

A novel Gram-stain-positive, rod-shaped, motile, endospore-forming and proteolytic bacterial strain, SPT, was isolated from Lonar soda lake, in India. On the basis of 16S rRNA gene sequence analysis it was identified as belonging to the class Firmibacteria and was most closely related to Bacillus cellulosilyticus DSM 2522T (96.7 %) and other members of the genus Bacillus ( < 95.9 %). Strain SPT was catalase- and oxidase-positive. The cell-wall peptidoglycan of strain SPT contained meso-diaminopimelic acid. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three phospholipids, two aminolipids and two unknown lipids. The predominant isoprenoid quinone was MK-7. Anteiso-C15 : 0 (26.8 %) was the predominant fatty acid and significant proportions (>5 %) of iso-C15 : 0 (20.9 %), C16 : 1ω7c alcohol (6.3 %), iso-C16 : 0 (6.3 %) and anteiso-C17 : 0 (5.3 %) were also detected in strain SPT. The DNA G+C content of strain SPT was 38.9 mol%. The results of phylogenetic, chemotaxonomic and biochemical tests allowed a clear differentiation of strain SPT from all other members of the genus Bacillus. Strain SPT represents a novel member of the genus Bacillus, for which the name Bacillus caseinilyticus sp. nov. is proposed. The type strain is SPT ( = MCC 2612T = JCM 30246T).