INVESTIGATION OF BACITRACIN FUNGICIDAL EFFECTS PRODUCED BY BACILLUS SP. ISOLATED FROM SOIL OF FOREST PARKS IN TEHRAN

Background and Aim:Bacitracins, ribosomally synthesized antimicrobial peptides, display potential applications in agriculture, medicine and industry. The aim of this study was optimization and partial characterization of a bacteriocin substance from a soil bacterium taxonomically affiliated as Bacillus sp .Methods:In this study eleven forest soil samples were collected from different regions of Tehran and for separating of Bacillus sp . After biochemical and molecular identifications, cellular metabolites of strains were extracted by centrifugation. Peptone yeast beef medium (PYB in g/L: 10 g peptone, 5g yeast extract and 3g beef extract) was used as a bacitracin core production medium. The fungicidal activity of Bacitracin against standard strains of Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger was investigated by means of Disk diffusion, Well diffusion, MIC and MFC methods.Results: The results showed that, 10 strains were collected from 11 strains of soil, belonged to Bacillus subtilis. The Minimum Inhibitory Concentration (MIC) of ethyl acetate extract against A. fumigates and A. niger , were 25.0 μg ml-1, and 12.5 μg ml-1, respectively. There are significant differences between the amount of fungal growth inhibition in the Disk diffusion, Well diffusion, MIC and MFC methods compared to the control group .Conclusion:It can be concluded that Bacillus subtilis might be a promising candidate for new pharmaceutical agents.

Keywords:

Bacillus subtilis , Bacitracin , Aspergilus , Fungicidal effect