Contribution of Enzyme Mechanism to Bioprocess Kinetic Models

2 Contribution of Enzyme Mechanism to Bioprocess Kinetic Models 

Microbial activities like growth and product formations can be regarded as a sequence of enzymatic reactions. On this basis Ferret (1960) constructed a kinetic model for a growing bacterial cell population. The main pathways for major nutrients are considered together with pathways for minor nutrients and trace elements linked to each other. This metabolic network can be simplified with the aid of the concept of the rate-determining step (rds), resulting in a master reaction or bottleneck that limits the total flux and the rate of the process. 

This picture can be used to demonstrate that enzymatic reactions are the center of kinetic considerations for microbial systems, even if it is hard to verify directly such a mechanistic approach in real fermentations. 

The differences between steady state, stationary state, and transient state may be clarified with the aid of a consecutive reaction of order n = 1  

The concentration time curve is presented in Fig. 5.9, which shows the ranges of the different states mentioned. 

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