Experimental and Modelling Studies of the Bioconversion of Glycerol to Succinic Acid by Actinobacillus Succinogenes

An unstructured kinetic model for the growth of Actinobacillus succinogenes on glycerol as the only carbon source is proposed in this study. The model describes cell growth considering both substrate and product inhibition. and its parameters are estimated by fitting the model predictions to experimental data. Substrate consumption and product formation rates are described by the Luedeking-Piret model. The main product of the process is succinic acid while by-products like acetate, formate and ethanol have very low concentrations. The main environmental factors that affect the bioprocess were examined and optimum conditions in terms of yield, final succinic acid concentration and productivity were evaluated by a factorial experimental procedure. The examined parameters were the supply of CO2, the pH level and the redox balance. Experiments using different initial glycerol concentrations at the “optimum” environmental conditions were carried out and simulation studies were performed using the proposed model.