A study on isolation, taxonomy and fermentation of streptomyces isolates these have highly antimicrobial activity from North Cyprus soils

Streptomycetes are Gram-positive, filamentous soil bacteria present in almost all kinds ofenvironments. They are very common in soil, but also found in sediments, composts, fodder,aquatic habitats and buildings. Streptomycetes are known to be producers of many secondarymetabolites, which have different biological activities, such as antibacterial, antifungal, antiparasiticand antitumor.A total of 251 culturable Streptomyces strains were recovered from soil samples collectedfrom North Cyprus and its surrounding. These were then assessed for their antimicrobial activityagainst Gram-Positive, Gram-Negative bacteria, moulds and yeasts.Results indicated that of 251 streptomycete isolates, 67 were active at least one of thetested organisms. Approximately 52.23% isolates produced antibacterial substances against onlyon Gr (+) bacteria, 5.97% isolates only against Gr (-) bacteria, 12% isolates against both Gr (-) andGr (+) bacteria and 16.41% isolates only against yeasts. According to primary antimicrobialscreening, 16 isolates were selected to find out of antifungal activities and 5 of them were activeagainst tested moulds. For fermentation studies, the most active four strains selected and only oneof them, namely Streptomyces sp. KEH23 showed antifungal activity ranging from 5 to 28 mm. onPDA medium against tested moulds.According to their antibacterial activity, four of the isolates were selected and characterizedby conventional methods.For isolation of antimicrobial molecule, fermentation studies carried out with 4 differentmedium. The most active isolate; Streptomyces sp. KGG32 was subjected to further fermentationstudies with medium including sucrose as a sole carbon source, and 2 different active substance(KGG32-A and KGG32-B) were isolated and purified by column chromatography on silica gel(Sephadex LH20) and finally partially characterized.Also, in this study some physiochemical properties of KGG32-A and KGG32-B weredetermined according to UV, IR, solubility in organic solvents and color reactions (Anisaldehyde,sulphuric acid, ferric chloride and ninhydrin).Key words: Streptomyces, isolation, soil, identification, antibiotic production and antimicrobialactivity.