Estimation of the kinetic constants and elucidation of trends in growth and erythromycin production in batch and continuous cultures of Saccharopolyspora erythraea using curve-fitting techniques.

The kinetics of erythromycin production were dependent on the identity of the growth rate-limiting nutrient during batch cultures of Saccharopolyspora erythraea. Semilogarithmic linear regression provided a single estimate of growth rate during the exponential phase, but partial cubic spline curve fit derivatives provided time-dependent specific growth and production rate profile. Non-growth-linked product formation was observed when the medium was glucose- or phosphate-limited. However, growth-linked product formation was observed in a nitrate-limited medium. The kinetics observed in nitrate-limited chemostat culture provided evidence that Saccharopolyspora erythraea may be subject to noncompetitive inhibition by a growth-linked product under these conditions. A mathematical model was used to test this theory. The model simulation fitted the observed data very closely and was used to calculate estimates of the kinetic parameters involved: [formula; see text]