| Abstract: | A simple model of colony growth and product accumulation in an agar disc was developed assuming constant rate of increase of colony biomass and a maturation- decay behaviour of the specific productivity of the biomass. Experimental data obtained with three erythromycin-producing strains of Streptomyces erythreus followed the predicted behaviour of the apparent specific productivity of the colony. The latter parameter exhibited a good correlation with the specific rate of product formation observed in liquid culture. A more sensitive correlation, and higher specific productivities, were obtained with agar discs made of a fermentation-type medium than with a maintenance-type medium. Estimation of the colony biomass through its surface area proved to be satisfactory in the conditions adopted, though it represents a major potential source of error. |
