Biosynthesis and optimization of bacitracin by mutant <em>Bacillus licheniformis </em>using submerged fermentation

251-260The bacitracin is an important antibiotic, which is being used in various biomedical fields. The bacitracin with zinc salt is used in poultry feed to promote growth and to minimize disease incidences. The present study was concerned with the low-cost production of bacitracin using mutant Bacillus licheniformis employing submerged fermentation. Mutant strain was developed from parent culture of B. licheniformis by UV irradiations for different time periods (5 to 40 min). The maximum bacitracin (235 IU/mL) produced by 25 min exposure culture was selected and designated as B. licheniformis PCSIR-410-(5). Culture and fermentation conditions of mutant strain were investigated to improve the yield. Maximum antibiotic (301 IU/mL) production was observed in a soybean meal containing a medium. The highest antibiotic yield was achieved using 24 h old 10% inoculums with 20% dissolved oxygen. While optimizing the conditions it was found that higher levels of antibiotic i.e. 168, 112, 208 and 208 IU/mL were measured at 400 rpm agitation with pH 7.0 at 35oC after 48 h. The result suggested that by using these optimizing conditions for production process by a mutant, B. licheniformis PCSIR-410-(5) and simple techniques for the recovery process, the cost of antibiotic can be decreased to a significant level. The mutated strain could be applied to produce antibiotic at industrial scale to obtain maximum yield