Monitoring the process values during biotechnological fermentations is of high importance for maintaining a high efficiency and quality of a bioprocess. For some variables, such as pH-value or the concentration of dissolved oxygen, commercial sensor systems for real time monitoring are available.
Optimizing and ensuring a high efficiency of a bioprocess also requires monitoring and controlling of other variables like a glucose consumption and the production of lactate. This can be achieved by different offline analyses. In this case one has to accept that the offline analysis has a long reaction time and for this reason only offers a limited process control. Much better suited technologies can be used directly in the fermenter. They will give a direct real-time feedback of the process variables which will lead to a full process control and ease the process understanding.
The use of process trajectories allows the control of a batch by comparing it to a golden batch. This enables real-time information out of the running process. Therefore process analyzers are indispensable tools within the PAT framework for monitoring critical process parameters. NIR spectroscopy enables multiparametric, non-invasive measurements of substrates, metabolites and products.
NIR spectra contain a large variety of information of different process characteristics. Batch trajectories combine all those pieces of information to a fingerprint of the process. A perfect process or “golden batch” trajectory can be defined which allows an easy quality estimation of future batches in real time. This powerful tool allows a guided sampling and helps to save batches by automatic alarm modes.