Production of potent bioactive compounds by certain streptomyces species / Fatima Hemaia Mohammed Motawe ; Supervised Ferial Mohamed Rashad , Ensaf Imam Dawoud , Nadia Hasan Tawfiek Abdelnasser

Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Microbiology

Screening, isolation and characterization are still the powerful strategies for searching about potent bioactive compounds of biotechnological importance. Accordingly, from twenty different soil samples collected from different area, 500 actinomycete isolates were recovered and screened for their ability to produce antimicrobial metabolite(s). Only 56 exhibited antimicrobial activities against the tested microorganisms. On the basis of antimicrobial activity, 10 promising isolates that exhibited antagonistic activity against at least one of each of gram negative, Gram positive and/or filamentous fungi in addition to candida were selected for further studies. Based on the morphological, cultural, physiological, biochemical and chemotaxonomical characteristics, the numerical identification using the UPGMA program, confirmed that the 10 active strains of streptomyces were assigned to three hierarchical clusters: first cluster consists of 7 strains, 2nd cluster consists of one strain and the 3rd cluster consists of two strains. The most potent strains FHM275 and FHM572 exhibited strong inhibitory effects against the tested multi drug resistant nosocomial strains ethyl acetate: chloroform (1:1) proved to be the best solvent system for extracting their bioactive compound(s) from the cultural filtrates

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