Modeling of batch experimental kinetics and application to fed-batch fermentation of Clostridium tyrobutyricum for enhanced butyric acid production

There has been a growing interest in the fermentative production of butyric acid because of its wide applications to chemical, food, pharmaceutical, and fuel industries. In this study, we constructed unstructured mathematical models to describe the kinetics of cell growth, product formation, and substrate consumption in the batch fermentation of Clostridium tyrobutyricum. All the parameters in the models were estimated by minimizing mean-squared errors between the predictions of the models and the experimental data obtained from a series of batch fermentations with different initial glucose concentrations ranging from 0 to 150g L-1. A Monod model supplemented with terms describing substrate inhibition and product inhibition, a Luedeking-Piret model and a carbon mass balance were employed to describe cell growth, butyric acid formation, and glucose consumption, respectively. The predictions of the models were in good agreement with the fermentation results. In addition, a model-based fed-batch fermentation showed increases in the production of butyric acid as well as the growth of C. tyrobutyricum. (C) 2010 Elsevier B.V. All rights reserved.