Influence of increased dissolved oxygen concentration on productivity and selectivity in cultures of a colabomycin-producing strain ofStreptomyces griseoflavus

The influence of enhanced O2 concentration on growth and formation of secondary metabolites byStreptomyces griseoflavus (strain Tu 2880) was investigated in a stirred tank and in an air-lift fermentor. At a partial pressure of O2 po2 = 1880 mbar the growth was lowered by 50% compared to po2 = 210 mbar, whilst substrate consumption and O2 uptake rate increased markedly. Production of the colabomycin complex reached maximum values at po2 = 630 mbar. A similar increase of secondary metabolite formation was obtained when glycerol or acetate were fed at po2 = 220 mbar. The portion of the derivate colabomycin A in the product mixture rose from 43% at po2 = 210 mbar to 73% at po2 = 1260 mbar. Since dissolved O2 concentration has a significant influence on productivity and selectivity it may be used to regulate aerobic fermentation processes.