Bacillus canaveralius sp. nov., an alkali-tolerant bacterium isolated from a spacecraft assembly facility

Two Gram-positive, rod-shaped, alkali-tolerant (pH 10.5), endospore-forming bacteria (strains KSC SF8bT and KSC SF10a) were isolated from surfaces within the Payload Hazardous Servicing Facility, where robotic spacecraft are assembled and tested before launch, at the Kennedy Space Center at Cape Canaveral. Based on 16S rRNA gene sequence similarities, these strains were shown to belong to the family Bacillaceae and the genus Bacillus. The highest 16S rRNA gene sequence similarity was approximately 97.5%, observed between the novel strains and Bacillus selenatarsenatis SF-1T. Several phenotypic characteristics, such as growth with 10% NaCl and assimilation of melibiose and lactose, were useful in the discrimination of this novel species from the closely related alkali-tolerant species Bacillus firmus and B. selenatarsenatis. DNA-DNA hybridization studies revealed reassociation values of less than 45% between strain KSC SF8bT and its closest genotypic neighbours. The combination of unique phenotypic and genotypic characteristics allowed the differentiation of these alkali- and halotolerant spore-forming strains from related Bacillus species, and a novel species, Bacillus canaveralius sp. nov., is proposed. The type strain is KSC SF8bT (=ATCC BAA-1493T=MTCC 8908T).