Protein Pressure Stability Impact (Prot P.S.I.)

Contact Persons: PD Dr. Monika Johannsen, M.Sc. Daniel Niehaus

Financing:  Federal Ministry of Education and Research (BMBF), 

grant number 031B0405A


1st project phase: 01/17 - 03/21

2nd project phase: 06/21 - 06/24

Project Website:

Partners Subproject B1:

Prof. Andreas Liese, Institute of Technical Biocatalysis (ITB);

Prof. Michael Schlüter, Institute of Multiphase Flows (IMS);

Dr. Gregor Liebsch, PreSens Precision Sensing GmbH, Regensburg


Schematic flow chart of the laboratory prototype


The use of enzymes for synthesis, especially of fine chemicals, has increased significantly in recent decades. A potential to increase their efficiency is the application in pressurized reactor systems. Studies have shown the increase in stability, activity as well as in selectivity, when high pressure is applied. Besides these effects gas consuming reactions can profit from higher gas solubility in aqueous systems under elevated pressure. In order to measure process parameters such as dissolved oxygen under these conditions, and thus to monitor the progress of the reaction and set up process control, there is a need for the development of new technologies for high-pressure reactor systems.


At the Institute of Multiphase Flows a aeriation solution for pressure reactors is being developed, which realizes an optimal gas input and mass transfer with minimized shear stress at the same time. For this purpose, the shear-intensive aeration is separated from the reaction chamber with shear-sensitive enzymes.

The oxidation of L-tyrosine to L-DOPA as a pharmaceutically interesting molecule will be investigated as a model reaction system for the newly developed technology. The biocatalysts to be used will be characterised comparatively under normal and high pressure conditions with regard to their activity, selectivity and stability. Laboratory samples and prototypes will be designed for the application of the new aeration and sensor units in the presence of the biocatalysts.The biocatalysts are immobilised on 3D printed structured packings optimised for application under pressure.

Within the scope of the project, the circulation reactor in combination with the spatially separated gassing unit and the carrier structures will be characterized in detail in terms of reaction technology. Fluorescence-optical sensors will be used to monitor the progress of the reaction via the dissolved oxygen concentration. The newly developed sensors will be adapted to the conditions in the prototypes with regard to pressure resistance and pressure change resistance.

Aeration at 5 and 40 bar operating pressure