Enhanced sinefungin production by medium improvement, mutagenesis and protoplast regeneration of Streptomyces incarnatus NRRL 8089.

Increased production of sinefungin, a very potent antifungal and antiparasitic nucleoside antibiotic was achieved by medium and strain improvement. When soybean-meal, dextrin and yeast extract were added as carbon and nitrogen sources to the fermentation medium, instead of corn steep liquor, soya-oil and glucose; the antibiotic yield increased from 40 micrograms/ml to 126 micrograms/ml with low biomass production. Strain improvement was attempted by two methods. The mean antibiotic yield of the variants after multistep mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine and ethyleneimine was 466 micrograms/ml. Protoplasts of the parental strain were prepared by lysozyme digestion from mycelia grown in a medium containing 0.7% glycine. The mean activity of the regenerated protoplasts was 664 micrograms/ml. Thus, the overall sinefungin production could be increased 16-fold.