Glucose-stimulated acidogenesis by Streptomyces peucetius

Cultures of Streptomyces peucetius often were observed to divert spontaneously from the production of anthracycline antibiotics to the excretion of acidic metabolites, whether grown in a defined medium or a nutrient-rich medium. The predominant excreted acidic metabolites were determined by high-performance liquid chromatography to be pyruvate and 2-oxoglutarate. The acidification occurred at high frequencies when glucose was the primary carbon source in a defined medium, at intermediate frequencies when fructose was the primary carbon source, and did not occur when either maltose, starch, or dextrin were used as primary carbon sources.