COMPARATIVE STUDY OF TWO BACTERIOCINS PRODUCED BY REPRESENTATIVE INDIGENOUS SOIL BACTERIA

The aim of this research work was to identify and characterized the bacteriocins produced by soil-associated bacteria. bacillocin from bacillus brevis bb and pyocin from pseudomonas aeruginosa pa were found bioactive only against gram-positive bacteria tested. maximum production of both the bacteriocins was observed at 32°c in bhi medium. production of both the bacteriocins started in the early exponential growth phase while the maximum production was observed during the stationary phase. bacillocin bb remained stable during 1-9 ph while pyocin pa remained stable at ph 1-11. both of the bacterocins were found resistant to high temperature (100°c for 30 min), detergents (1% solutions of edta, tween 20, tween 80 and sds) and organic solvents (1% solutions of ethanol, butanol, methanol, propanol, chloroform, and acetone). activity of both was completely lost after proteinase k treatment suggesting their protein nature. titre of bacillocin bb was estimated to be 5280 au/ml while the titre for pyocin pa was calculated as 640 au/ml. both of the bacteriocins showed bacteriolytic mode of action against the indicator bacillus strain bc31 and were found <10 kda in their molecular mass.