In order to keep the ethanol concentration in R2 at approximately
80 g L1, a third reactor was used to produce fresh yeast
cells, and the fresh yeast cells were continuously fed into R2 to
replenish viable cells and enhance the activity. In our previous
study, it had been proven that the sugar concentration between
80 g L1 and 100 g L1 resulted in the highest cells activity at 30 C