OSCILLATORY PENICILLIN FORMATION IN CARBON-LIMITED BATCH FERMENTATIONS OF PENICILLIUM-CHRYSOGENUM

Circadian oscillations of penicillin productivity with a period of 22 +/- 2 h have been observed in carbon-limited batch fermentations of Pe nicillium chrysogenum. The specific penicillin production rate oscilla ted with an amplitude of 20 to 100% of its mean value, depending on th e growth rate of the active (respiring and producting) biomass. In spi te of this, the penicillin concentration increased almost linearly if the optimum growth rate of the active biomass for maximum penicillin p roductivity was maintained using microprocessor control. This apparent ly inconsistent behaviour of the fungus is discussed on the basis of c haos theory.