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    Item type:Publication, Access status: with files ,
    Gas-Liquid Flow, Oxygen Mass Transfer, and Mixing Characterization of a Transparent Single-Use Bioreactor Model (Biostat STR® 200)
    (Sartorius, 2025)
    Scheibenbogen, Karl
    ;
    Maly, Marc
    ;
    Bernemann, Vincent
    ;
    Fitschen, Jürgen
    ;
    Leupold, Marco
    In recent years, the biopharmaceutical industry has had to become more flexible and increase upstream yields, driving the uptake of process intensification strategies such as perfusion. This requires production equipment to support high cell density cell cultures requesting an oxygen uptake rate of 20 mmol O2 L-1 h-1 and above. Testing equipment capabilities typically involves characterization approaches such as determining oxygen mass transfer, energy input, and mixing performance. A broad measurement database and an appropriate mass transfer model CFD can be applied to better predict culture impact. However, cell activity sometimes deviates from expectations, and empirical validation of the used model is often lacking. In this research, a transparent version of the Biostat STR® 200, made of acrylic glass, was erected at the Institute of Multiphase Flows at Hamburg University of Technology to gain deeper insights into the two-phase flow pattern. The gas distribution and mixing behavior were investigated using high-resolution pictures and videos. In these assessments, two different stirrer combinations have been investigated for varied aeration rates and stirrer frequencies. With regards to oxygen mass transfer rate, the acrylic reactor replica behaves similarly to the industrial single-use bioreactor system, with deviations lying within the predefined ranges determined by the Sartorius Biostat STR product characterization approach. The volumetric mass transfer coefficient kLa is also comparable for both reactors. Consequently, it can be assumed that the visual recordings from the transparent model reflect dynamics from industrialized single-use cultivation chambers. Furthermore, high-resolution imaging of the acrylic replica of the Biostat STR® 200 enabled the systematic characterization of the mixing and mass transfer performance, helping us to understand the influence of stirrer speeds and gassing rates in combination with different sparger and impeller types as well as their interaction.
    Publicationtype: Learning Object
      73  301
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    Item type:Publication, Access status: with files ,
    Characterization data for the establishment of scale-up and process transfer strategies between stainless steel and single-use bioreactors
    (Multidisciplinary Digital Publishing Institute (MDPI), 2024-05-16)
    Bernemann, Vincent
    ;
    Fitschen, Jürgen
    ;
    Leupold, Marco
    ;
    Scheibenbogen, Karl-Heinz
    ;
    Maly, Marc
    The reliable transfer of bioprocesses from single-use bioreactors (SUBs) of different scales to conventional stainless steel stirred-tank bioreactors is of steadily growing interest. In this publication, a scale-up study for SUBs with volumes of 200 L and 2000 L and the transfer to an industrial-scale conventional stainless steel stirred-tank bioreactor with a volume of 15,000 L is presented. The scale-up and transfer are based on a comparison of mixing times and the modeling of volumetric mass transfer coefficients kLa, measured in all three reactors in aqueous PBS/Kolliphor solution. The mass transfer coefficients are compared with the widely used correlation of van’t Riet at constant stirrer tip speeds. It can be shown that a van’t Riet correlation enables a robust and reliable prediction of mass transfer coefficients on each scale for a wide range of stirrer tip speeds and aeration rates. The process transfer from single-use bioreactors to conventional stainless steel stirred-tank bioreactors is proven to be uncritical concerning mass transfer performance. This provides higher flexibility with respect to bioreactor equipment considered for specific processes.
    Publicationtype: Journal Article
      38  98