Dynamic modeling of the pH in lactic acid fermentation processes

For the present paper there was proposed a global dynamic model for the lactic acid fermentation process able to describe the main variables of the biological system and to enable the prediction of the pH in the culture broth. The model, based on mass balance considerations, consists in the coupling of two sub-models, namely a biological model and a chemical speciation model. The biological model allows the prediction of biomass, substrate and product concentrations, while the chemical speciation model is a computational package that quantitatively describes each molecular and ionic species of the system. There were investigated the sensitivities of the biomass, substrate and lactic acid equations to parameters, thus the most influential parameters being identified.