Isolation and identification of antimicrobial Actinomycetes strains from Saudi environment

Actinomycetes are highly economic and biotechnologically valuable prokaryotes able to produce wide range of bioactive secondary metabolites such as antibiotics, antitumor agents, immunosuppressive agents and enzymes. Almost 80% of the world’s antibiotics are known to come from Actinomycetes, mostly from the genera Streptomyces and Micromonospora. Around 100 antibiotics have been commercially used to treat human, animal and plant diseases. The genus, Streptomyces is responsible for the formation of more than 60% of known antibiotics. Actinomycetes from different environments of Jeddah and Al-Madinah Al-Munawwrah have been isolated and screened against some pathogenic bacteria and fungi. Factors affecting growth and antimicrobial production by the selected Actinomycetes isolates were studied and the effect of the culture filtrate on morphology of the cell, and cell growth and cell wall composition of the tested microbes were also studied. Results showed that the most active antimicrobial isolate was D8 from Madinah location. This isolate was molecularly identified using 16srRNA as Streptomyces flavogriseus (KF235416).