Antifungal Activity of Producing Biosurfactant by Rhodotorula Species in Vitro

Objectives: Biosurfactants are amphiphilic surface-active compounds that are produced by several microorganisms such as bacteria and fungi. Recent studies shows that some of the biosurfactants produced by microorganisms have antibacterial, antifungal and antiviral activities. The main aim of the present study was to determine antifungal activity of producing biosurfactant by the strains of Rhodotorula in vitro. Methods: In the present study, the anti-fungal activity of the crude biosurfactant produced by Rhodotorula against several fungi was determined by direct spotting method in plates. A standard suspension of fungal elements was prepared and inoculated on the surface of culture media as lawn. Different serial dilutions of biosurfactant in DMSO was prepared. Several methods including spotting, disk diffusion and well diffusion were used for the detection of MIC. All plates were incubated at appropriate temperature and the lowest concentration which inhibited the visible fungal growth was considered as the MIC value. Results: In the present study, MIC for several species of Candida albicans, Aspergillus niger, A. flavus, Alternaria, Rhizopus and Syncephalastrum were detected. Our results showed that biosurfactant produced by Rhodotorula glutinis has the best effect against tested organisms at the range of 10-40 μl. Conclusion: In conclusion, in this study we have demonstrated the anti-fungal properties of the crude biosurfactant produced by Rhodotorula against several pathogenic and nonpathogenic yeasts and filamentous fungi. Our results suggest the possible use of this biosurfactant as an alternative antifungal agent in the medical field.

Biosurfactant