ENHANCED SINEFUNGIN PRODUCTION BY MEDIUM IMPROVEMENT, MUTAGENESIS, AND PROTOPLAST REGENERATION OF STREPTOMYCES INCARNATUS NRRL 8089

Abstract

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 μg/ml to 126 μg/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 μg/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 μg/ml. Thus, the overall sinefungin production could be increased 16-fold.