Unstructured modelling growth of Lactobacillus acidophilus as a function of the temperature

We present modelling software developed under MATLAB in which parameter estimations are obtained by using non-linear regression techniques. The different parameters appear in a set of non-linear algebraic and differential equations representing the model of the process. From experimental data obtained in discontinuous cultures a representative mathematical model (unstructured kinetic model) of the macroscopic behaviour of Lactobacillus acidophilus has been developed. An unstructured model expressed the specific rates of cell growth, lactic acid production and glucose consumption for batch fermentation. The model is formulated by considering the inhibition of growth under sub-optimal culture conditions during Lactobacillus acidophilus fermentation, which is accompanied by an increase of the maintenance energy. This study permits to predict the cellular behaviour at low growth temperatures and enables to define the response of the strain to sub-optimal temperature stress.