Isolation and Characterization of a Streptomyces Strain Endowed with Antifungal Activity

An actinomycete strain, named H3, was recovered from a deteriorated wood sample of an old house located in the Medina of Fez, Morocco. Molecular identification via 16S rDNA amplification and sequencing showed that it belongs to the genus Streptomyces. Screening of this strain for its antimicrobial activity against different Gram positive and negative bacteria, yeasts and fungi showed that it was active against yeasts and fungi and had no activity against bacteria. The antifungal activity of the organic extract of strain H3 wasn't eliminated upon treatment by Proteinase K and heat, revealing its non-protein nature. Moreover, this organic extract was able to release nucleic acids of Candida tropicalis indicating that it acts probably on the yeast envelope. In addition, the study of the production kinetics of strain H3 in ISP2 broth showed that the maximum of production was obtained at the 9th day of fermentation:. Otherwise, thin layer chromatography followed by bioautography using C. tropicalis as test organism, allowed localizing the active substance of strain H3. Furthermore, the phytochemical tests carried out showed the presence of flavonoids and polyphenols in the organic extract of strain H3.