advanced mixing technology

Magnetic Mixing Technology for XXL Fermenter

Scaling up mixing processes from laboratory to industry scale is a big challenge because of the conflicting demands on the mixing time, shear forces and hygienic design.

The demand from the biotech industry for bigger and bigger vessels for cell cultures, without any quality loss due to inadequate mixing, is huge.

To meet these requirements, the ZETA bottom-mounted agitator has been put through a program of testing for its use in XXL fermenters in a collaborative project with Boehringer Ingelheim and the Institute of Multiphase Flows at Hamburg-Harburg University of Technology.

ZETA’s prototype of the bottom-mounted magnetic agitator was tested extensively in a 15,000 L fermenter over a period of four months.

The collected results confirmed that the prototype is applicable to vessel sizes up to 30.000 L.


The tests were successful and the agitator achieved everything that was demanded of it:

  • Magnetic drive with excellent power coupling
  • Long shaft free from problematic oscillations
  • Optimized rotor blades (geometry and arrangement)
  • Vessel sizes up to 30,000 L possible
  • Mixing pattern reproducible for different vessel sizes
  • Meets hygienic design standards and is sterilisable
  • Exclusion of microbiological contamination risks
  • Cost-efficient thanks to lower operating costs and easy maintenance
  • Easy conversion from shaft-driven agitators to magnetic drive forms

For the tests the agitator was installed in a 15,000 L acrylic glass reactor and underwent a series of trials using different impeller configurations (1–3 stage impellers) to gather the data required for a full understanding of the mixing process and the parameters needed to achieve aseptic operation.

The results obtained from the experiments show that the new agitator model for bioreactors is suitable for use in reactors up to 30,000 L.

If you are interested in more details, don´t hesitate to request the full test report under the following link >>

 „The need for optimized large-scale industrial fermenters has grown enormously and will continue to rise steadily. Firstly, because biocatalytic processes play a major role in the shift towards using renewable raw materials to produce basic chemicals and substances. And secondly, because the efficiency of microorganisms and cells for the production of substances has increased considerably in the last years. In order to meet the requirements of these accelerated metabolic processes a better supply of e.g. oxygen has to be guaranteed. For the execution of trials to enable further development of Boehringer’s fermentation processes of tomorrow a transparent 15.000 L test facility was installed at Hamburg-Harburg University of Technology.”

Prof. Michael Schlüter (Institute of Multiphase Flows, Hamburg-Harburg University of Technology on the trend towards production processes in large bioreactors.



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