Process Analytical Technologies (PAT)

Monitoring methods are of increasing importance for process development and production in the meaning of Quality by design.

Beside traditional fields of the application of process analytical tools like biopharma, anaerobic processes like brewing and biogas production are in the focus of the development and application of novel sensors. The latter process is still a black box, while the ongoing transmission of energy supply demands a maximum of efficiency and flexibility of biogas processes in terms of substrate utilization and energy provision. The goal is a better integration of processes into closed supply chains and smart grids with enhanced monitoring strategies and process control.

In order to increase the knowledge about gradients and their impact on the process performance in large-scale processes, multiposition sensors for real time in situ monitoring in different zones in the liquid core of bioreactors are developed. Applying this (micro-) sensor technique, the temperature, pH, dissolved oxygen and carbon dioxide, redox potential, and conductivity is measured simultaneously. The obtained data from the large scale is suitable for the design of experiments in a scale-down experiments, and for the identification of critical zones.

• Improved monitoring of biogas processes


• Modelling of a flexible operation of biogas plants


• Multiposition sensor application in brewing fermenters

Process characterization should directly include the monitoring of population heterogeneity, the optical features of the cell and other surface and morphological characteristics. Of special interest is the replacement of ex situ methods like flow cytometry by in situ methods. Tools like the electrooptical measurement of the cell polarizability or laser-based reflection sensors provide valuable information of the cell viability. The sensor probes are applied as process analytical tools for process evaluation and control.

• Improved observation of biogas processes with electrooptical monitoring

• Monitoring cell population heterogeneity of yeast and bacterial cultivations under an oscillatory environment

• Monitoring of the cell size for on line prediction of the fatty acid synthesis in microalgae