Isolation of bacillus subtilis MH-4 from soil and its potential of polypeptidic antibiotic production

The genus Bacillus produces mainly polypeptide antibiotics such as bacitracin and polymyxin. Bacillus species were isolated from soil by soil sprinkle technique. And all were screened for the production of antibiotic. Bacillus subtilis MH-4 gave the maximum antimicrobial activity so finally selected for optimization. During optimization of culture conditions for Bacillus subtilis MH-4 best antibacterial activity was obtained at 96 hours of incubation period, at pH-8 and by using glycerol as carbon and L-glutamic acid as nitrogen source. Optimum temperature for antibiotic production was 37 degrees C. The antibiotic was confirmed to be bacitracin by paper chromatography. Antibiotic was further extracted successfully with 1-Butanol, and aqueous concentrate showed activity of 0.8 mg/ml. The antibiotic so produced was found to be narrow spectrum active against only Gram-positive bacteria.