Application of the macroscopic electric charge balance in fermentation modeling

This article treats the application of the macroscopic electric charge balance in fermentation modeling. From the presented calculations it follows that the definition formula of the so‐called degree of reduction is changed due to the ionic character of the fermentation reactants. It is also shown that the macroscopic electric charge balance, together with the ionic equilibria between fermentation reactants, leads to an expression for the calculation of the pH during fermentation. Finally it is concluded that one should be very careful in the estimation of biomass production from the acid or base feed rates which are necessary for pH control.