Background: Biosurfactants are amphiphilic biological compounds produced extracellularly by a variety of microorganisms. Because their use in various industries are of a particular importance. The aim of this study was to identify a strain of bacteria of the genus Bacillus Cereus biosurfactant producers and investigate the antibacterial effects of biosurfactant produced.

Materials and Methods: In this study, different samples of oil, water and soil contaminated with oil were prepared. Hemolytic activities, emulsification and measurement of surface tension were used and selected strains were identified by biochemical tests. The nature and effect of antibacterial biosurfactant were evaluated for strain selection.

Results: In this study, eighty eight bacterial strains were isolated. Among them, 24 strains were hemolytic activity. Among them, 14 strains have emulsification activity more than 70% and finally from among them four strains were able to convey to the surface tension of less than 40 mN/m. On the basis of biochemical tests, a strain selective in this study as B. cereus 43 strain, were identification and selection. The results of investigating the nature biosurfactant determined that the type of lipopeptide. Also, the produced biosurfactant has antibacterial activity against six bacterial infectious. The most sensitive and the most resistant bacteria than the impact of biosurfactant extract, of S. aureus PTCC1112 and of the Proteus mirabilis ATCC 2601 respectively. Also, the results of MIC, MBC showed that MIC extract were effective in a dilution of 63 mg/ml on S. aureus PTCC1112 and S.epidermidis ATCC 2405 and the MBC extract had the greatest effect in a dilution of 125mg/ml on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa PTCC 1074 respectively.

Conclusion: Bacillus Cereus 43 had high potential in reducing the surface tension and biosurfactant extracted had high antibacterial effects. Therefore, Frequency of potential has for applications of biotechnology and the environment.