Actinomycetes are well- known for their ability to produce antibiotics. The known antibiotics produced by Actinomycetes range in complexity from very simple compounds to very complex proteins. Among Actinomycetes, Streptomyces produce over two thirds of the clinically useful antibiotics of natural origin found predominantly in soil and decaying vegetation. The aims of this study are isolation of Actinomycetes which suggested being as antifungal- producers, studying their antifungal activities and characterizing their secondary metabolites. Twenty five Actinomycetes species were isolated from thirty samples of soil collected from Tuti Island farms and Blue Nile river bank using Starch Casein agar medium. Three genera were isolated, nineteen different species were belonging to Streptomyces, five species belong to Actinomyces and one species belongs to Arachnia formerly Actinomyces. They were screened and evaluated for their antifungal activity against Aspergillus fumigates and Candida albicans. The results showed that Aspergillus fumigates was affected by all isolated Actinomycetes, while Candida albicans has a resistance to the antifungal activity of most isolated Actinomycetes, and it has an ability to destruct the secondary metabolites. The crude extracts of fermented actinomycetal broth were analyzed by thin layer chromatography (TLC) technique and seventeen different antibiotics were characterized. We concluded that the Sudan soils consists a very diverse, useful antifungal-producer Actinomycetes which have ability to inhibit the growth of phytopathogenic and human and animal causes fungi.
Key words: Actinomycetes, Aspergillus fumigatus, Candida albicans, TLC, Antifungal activity, Streptomyces