where α and β are kinetic constants.
For sucrose-based media, the Equations (7.1) through (7.6) were also applied
using not only glucose as a substrate, but also fructose. In this case, it was considered
that the cell growth rate is equal to the sum of the growth rates from both
substrates. For starch-based media, the same kinetic expressions for glucose content
were used considering the content of this sugar in the saccharified starch.
The stoichiometric approach can be useful as an approximation method to
describe the ethanologenic fermentation from media containing glucose, fructose,
or sucrose. In this case, the overall biological transformations are considered
through specific key chemical reactions including the global reaction for biomass
cell biosynthesis. Thus, the fermentation employing sucrose-based media may be
described by the following reactions: