An Investigation into the Antibacterial Activity of Pigmented Secondary Metabolites Isolated from Streptomyces from Windhoek Soil Antibacterial Activity of Pigmented Secondary Metabolites

A Iikasha, H Eiman, D Mumbengegwi
Int. Sci. Technol. J. Namibia   unpublished
There is an increase in mortality from infectious diseases due to an increase in antibiotic resistance worldwide. Hence, this study aimed at investigating the antibacterial activity of Streptomyces that produces pigmented secondary metabolites. The soil samples were collected from 3 different sites in Windhoek. Streptomyces were isolated on starch casein agar. Biochemical and physiological tests were used to identify Strepto-myces species. Casein slant agar method was used for preliminary
more » ... cterial test. Chloroform and n-Hexane were used to extract secondary metabolites by solvent-liquid extraction method. Thin layer chromatography plates were used for antibacterial activity of the isolated secondary metabolites. Minimum inhibitory concentration of isolated secondary metabolites was determined by the broth dilution method at concentrations ranging from 50 to 1.5 µg/ml. Six out of nine Streptomyces isolates showed antibacte-rial activity against at least one of three test bacteria. Streptomyces isolate 1 exhibited potent activity of 19.5 mm ± 0.056 against M. avium. Different pigmented secondary metabolites were produced and showed antibacterial activity against at least against one of three test organism. Streptomyces isolate 4 and 6 showed the lowest minimum inhibitory concentration of 6.25 µg/ml against M. avium and E. faecialis. The results showed that Windhoek soil contain antibiotic producing Streptomyces.