An investigation into the antibacterial activity of pigmented secondary metabolites isolated from streptomyces from Windhoek soil

Abstract

There is an increase in mortality from infectious diseases due to an increase in antibiotic resistance worldwide. Hence, his 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 case in agar. Biochemical and physiological tests were used to identify Streptomyces species. Case in slantagar method was used for preliminary anti-bacterial 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 tabolites.Minimum inhibitory concentration of isolated secondary metabolites was determined by the broth dilution method at concentrations ranging from 50to1.5 μg/ml. Six out of nine Streptomyces isolates showed antibacterial activity against at least one of three test bacteria. Streptomyces isolate 1exhibited potentactivityof19.5mm ± 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.