Antibacterial and cytotoxic activity of Bacillus methylotrophicus-SCS2012 isolated from soil.

Abstract

The strain Bacillus methylotrophycus-SCS2012 (Bacillus sp. SCS2012) identified by 16S rRNA gene sequencing was isolated from soil. Ethyl acetate extract of B. methylotrophycus-SCS2012 showed antibacterial activity against both Gram positive and Gram negative bacteria. The crude metabolite extracted from B. methylotrophycus-SCS2012 exhibited strong antibacterial activity against Streptococcus agalactae, Bacillus cereus, Escherichia coli, Shigella sonnei and Shigella dysenteriae with the zone of inhibition range 28.33 to 32.16 mm at 100μg/disc. Minimum inhibitory concentration (MIC) of the extract against Streptococcus agalactae, Bacillus cereus, Escherichia coli, Shigella sonnei and Shigella dysenteriae was found to be 156, 156, 312, 312 and 625µg/ml respectively. The ethyl acetate extract also exhibited cytotoxic effects on brine shrimp lethality bioassay with LC50 value of 10.78 g/ml. Thus the ethyl acetate extract of Bacillus methylotrophycus-SCS2012 has broad spectrum activity with moderate cytotoxicity.