For formulation of the double substrate model, the
microbial growth on each sugar is represented by
the specific growth rates of recombinant Z. mobilis
ZM4(pZB5) on glucose and xylose as single carbon
sources. The basis for these equations was taken from
a previous model development for Z. mobilis ZM4 for
growth and fermentation of glucose (Lee & Rogers
1983). The equations assume Monod kinetics for substrate
limitation and ethanol inhibition, with both a threshold level and a maximum inhibitory concentration,
as well as a typical substrate inhibition term.
These relationships are represented by Equations (2)
and (3).
For glucose: