Glucose repression of anthracycline formation in Streptomyces peucetius var. caesius

The effect of glucose on growth and anthracycline production by Streptomyce s peucetius var. caesius was examined in a chemically defined medium. Gluco se concentrations above 100 mM inhibited anthracycline synthesis in the ori ginal strain without causing significant change in growth and final pH valu es. This effect was observed when the carbohydrate was added initially or a fter 24 h fermentation, but not when added during the stationary growth pha se. When the microorganism was pregrown in 100 mM glucose and then transfer red to a resting cell system with 444 mM glucose, no significant difference s in antibiotic production were observed compared to the control without gl ucose. The negative effect of glucose on antibiotic synthesis was not obser ved in a mutant (2-dog(R)-21) resistant to growth inhibition by 2-deoxygluc ose. Glucose consumption by this mutant was approximately 30% of that utili zed by the original strain. Compared to the original strain, the mutant 2-d ogR-21 exhibited a reduction of 50% in glucose transport and an 85% decreas e in glucose kinase activity. The experimental evidence obtained suggests t hat glucose represses anthracycline formation in a transitory manner and th at this effect is related to glucose transport and phosphorylation.