Kinetic modelling of batch ethanol production from sugar beet raw juice

This study examines the kinetics of a batch fermentation process of raw juice, an intermediate product of sugar beet processing, by free Saccharomyces cerevisiae yeast cells, with the aim of producing bioethanol. Defining the kinetics and kinetic parameters of this bioprocess may be regarded as an important step towards translating it to industrial scales (scale-up). The optimal values of the kinetic parameters were determined by fitting the models into the experimental data, i.e. by minimising the discrepancy between the model predictions and corresponding experimental data. The growth of yeast cells could be expressed by a logistic function model, which describes the growth as a function of initial biomass concentration, fermentation time, specific growth rate and final biomass concentration. The modified Gompertz model, which gives the bioethanol production lag time, the maximum bioethanol production rate and the maximum bioethanol concentration, was able to describe the formation of bioethanol as the fermentation proceeded. These models thus can be employed for further development of the bioethanol production process from sugar beet raw juice.