Improved Bioreaction Kinetics for the Simulation of Continuous Ethanol Fermentation by Saccharomyces cerevisiae

A kinetic model for the production of ethanol by Saccharomyces cerevisiae has been developed from semiempirical analysis. The values for the parameters in this model were then determined by nonlinear multiple regression using the data of Bazua and Wilke ( 1977). The final equations were μ=0.427s(1‐(p/101.6)1.95)/(0.245+s), YX/p=0.291, and YX/s=0.152(1‐p/302.3). This model was then used to simulate a continuous stirred tank fermentor (CSTF) and compared to other models using the same experimental data but different kinetics. The equations required to use these kinetics in a CSTF with recycle were then developed. From this simulation, it was found that, for a CSTF with recycle, the best configuration to operate is an external recycle, with a low bleed and recycle ratio.