Simulation and Model Validation of Batch PHB Production Process Using Ralstonia eutropha

Mathematical modeling and simulation of microbial Polyhydroxybutyrate (PHB) production process is beneficial for optimization, design, and control purposes. In this study a batch model developed by Mulchandani et al., [1] was used to simulate the process in MATLAB environment. It was revealed that the kinetic model parameters were estimated off the optimal or at a local optimal point. Therefore, an optimization program was written using MATLAB codes to estimate those parameters again. It resulted in a significant improvement in the accuracy of Mulchandani’s kinetic model. The batch model was evaluated using two batch experiments performed in this work and also Mulchandani’s batch data when kinetic model parameter values estimated in this work were used. Visual comparisons between the model profiles and experimental data indicate that the model represents the process reasonably. A goodness of fit criterion used in this work and some similar researches proved higher accuracy of Mulchandani’s model using this work’s kinetic parameter values compared to other models. Theoretical model verification was also performed that lead to identification of the possible limitations of the model.