Modeling of typical microbial cell growth in batch culture

Abstract

A mathematical model was developed, based on the time dependent changes of the specific growth rate, for prediction of the typical microbial cell growth in batch cultures. This model could predict both the lag growth phase and the stationary growth phase of batch cultures, and it was tested with the batch growth of Trichoderma reesei and Lactobacillus delbrueckii. Modeling and simulation of microbial cell growth is important both theoretically and practically. Although the Monod model (1) has been the most widely used for the prediction of cell growth, it only fits the exponen- tial growth phase of the growth, without any inhibi- tion. The lag growth phase, decreased growth phase and the stationary growth phase of a typical microbial batch culture growth curve can not be predicted using the Monod model. The typical growth curve of batch culture is the result of continuous changes of the spe- cific growth rate, µ, with culture time. Although many efforts have been made to expand the Monod model in order to predict the typical microbial growth curve of batch culture, the time dependent changes of µ were often neglected in prediction of the lag growth phase. Efforts made to predict the lag growth phase simply defined the lag time in terms of cell growth, t L (2,3). The lag growth phase was related with the changes of µ and defined in the following way (3):