Heat-shock Technique for Isolation of Soil Bacillus Species with Potential of Antibiotics Secretion in Saudi Arabia

Abstract

The present research aimed to isolate soil Bacillus spp. from Al-Ahsa Province, Kingdom of Saudi Arabia, and test their potential of antibiotics production. Out of 21 soil samples, 34 bacterial isolates were obtained and following identification tests, 26 bacterial isolates in an isolation rate of 76.5% were identified as Bacillus spp by conventional methods and commercial automated identification system.  Identified species were Bacillus subtilis (7 strains), B. polymyxa (4 strains), B. licheniformis (4 strains), B. cereus (3 strains), B. mycoides (3 strains), B. pumilus (1 strains), and Bacillus spp. (4 strains). Disk diffusion test was employed to test the metabolites in sterilized cell free supernatant of isolates against some selected pathogenic bacterial species. The test indicated that B. polymyxa, B. licheniformis, B. cereus, B. mycoides and to a lesser degreeB. subtilis produced promising anti-microbial effects on tested bacterial species comparable to standard antibiotic disk. The study suggests that some of Bacillus spp from the study area have potential to produce antibiotics that may be used to control microbial growth.