Phenotypic and Genotypic Characterization of facultative and obligate Alkalophilic Bacillus sp. isolated from Saudi Arabia alkaline soils

Isolation and identification of new alkalophilic Bacillus strains have been increasing interest due to their possessing valuable and commercially interesting enzymes. In the present study, a total six obligate and facultative alkalophilic isolates were isolated from desert soil around the Al-qunfotha city, Saudi Arabia. All isolates were phenotypically and genotypically characterized. Among these isolates; AS3, AS4, AS5 and AS6 could grow at pH 9, 10, 11 and 12, but could not grow at pH 7, indicates that these isolates are obligate alkalophiles. While, isolates AS1 and AS2 grew at pH ranged from 7 to 10, but could not grow at pH 11 and 12, suggesting that they could be facultative alkalophiles. All isolates could hydrolyze casein and starch, indicating that they possess interesting amylase and protease enzymes. Based on 16S rDNA data, the phylogenetic analysis of these strains showed that all six alkalophilic Bacillus belonged to Bacillus cohnii with 99% similarity. The nucleotide sequences of 16S rRNA gene for the six isolates were deposited in a Gene-bank under accession numbers; KP053301, KP053302, KP053303, KP053304, KP053305 and KP053306, respectively.