| Abstract: | The kinetics of batch fermentation during the growth of S. cerevisiae ATCC 36859 was studied in various glucose/fructose mixtures. It was found that the growth is inhibited equally by glucose and fructose even though fructose is not consumed to any large extent by the yeast under the conditions tested here. The inhibition of growth by the substrate and ethanol is represented by linear equations. These equations were combined with the MONOD expression in order to formulate equations for the biomass growth, glucose and fructose consumption and ethanol production. Parameter estimates were obtained by fitting these equations to batch fermentation data and so developing models which indicate that the growth is completely inhibited when 62 g/l ethanol is produced by the yeast, while glucose consumption and ethanol production continue up to an ethanol concentration of 152 g/l. Products containing a high concentration of fructose are best produced by using a high initial biomass concentration. |
