Streptomyces rimosus produces antibiotic oxytetracycline (OTC) and is one of the most intensively studied streptomyces species. High yields of oxytetracycline makes S. rimosus an attractive host for potential heterologous production of polyketide based secondary metabolites. The objective of this thesis was to obtain an S. rimosus strain with the deletion of otc gene cluster. The deletion was carried out with the method of homologous recombination. In order to complete deletion, we constructed a temperature sensitive plasmid vector with all the necessary elements to carry out homologous recombination experiment. Homologous sequences of different lengths were designed to anneal on both sides of otc gene cluster. To obtain potential mutants we used a method of subcultivation and patching on agar plates with and without added selection marker (erythromycin). Colonies which did not show any OTC production were tested with polymerase chain reaction (PCR), sequencing, thin layer chromatography (TLC) and high-pressure liquid chromatography (HPLC).
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