MATHEMATICAL MODELING OF FED-BATCH ETHANOL FERMENTATION: EFFECT OF THE INOCULUM SIZE

This study evaluated the influence of the initial cellular concentration or inoculum size (CX0) on the fed-batch ethanol fermentation. A kinetic hybrid model considering the inhibition by substrate, ethanol and cells was used. The results showed that the increase in the cell concentration from 51.91 to 84.53 g L-1 led to increase in the ethanol productivity from 8.83 to 10.22 g L-1 h-1, respectively. However, cell concentrations greater than 84 g L-1 do not increased the ethanol productivity. As the cell concentration increased, an increase in the value of the cell inhibition power parameter ("m") was observed, which was correlated with the inoculum size (CX0).