Abstract
On-line computer control for the cultivation of Saccharomyces cerevisiae was developed by using a control law based upon an adaptive model. The model parameters were identified at each control step. The feed rate was taken as the input variable and the respiratory quotient as the output variable. Two weighting factors were used to ensure that the model had good tracking properties and that the estimated parameters were convergent. Experimental results indicated that for both batch-fed and continuous cultivations, feed rates changed smoothly. A quasi-steady state occurred for batch-fed cultivation under a constant respiratory quotient of unity.