Generation of mutant strains of Streptomyces violaceusniger yced-9 by the use of uv mutagenesis.

Streptomyces violaceusniger YCED-9 was discovered as a biocontrol agent of fungal plant diseases, and was described to produce several compounds with antimicrobial potential. The strain produces nigericin, guanidylfungin A and Geldanamycin. Geldanamycin is a well-known benzoquinone which is nowadays commercialized as an antitumoral for the treatment of primary tumors in different tissues and organs. A study was conducted to improve a culture medium for the spore production, and to detect sporulation mutants. By the use of UV mutagenesis, several stable hypersporulating mutants (HS) which produced spores either more abundantly, earlier during plate incubation, or both, were obtained. A chemical screening of those mutants allowed the selection of 2 stable mutant strains which produced high geldanamycin in two different culture media during submerged fermentations. The global cost of geldanamycin production is being substantially reduced. Studies regarding the production of other antimicrobials in the selected mutants are on their way.