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Johannes Tramper - One of the best experts on this subject based on the ideXlab platform.

  • Carbon Dioxide Evolution Rates in Animal Cell Culture in Bicarbonate Buffered and Bicarbonate Free Medium
    Animal Cell Technology: Developments Towards the 21st Century, 1995
    Co-Authors: H.p.j. Bonarius, Johannes Tramper, C. D. De Gooijer, Georg Schmid
    Abstract:

    The determination of the respiration quotient (RQ = CER/OUR) has so far not been used as a tool for understanding Animal Cell metabolism. This has been due to problems in measuring the carbon dioxide evolution rate (CER) rather than the oxygen uptake rate (OUR). The determination of the CER is complicated by the use of bicarbonate in the medium. Here the problems that arise due to bicarbonate are addressed briefly and a control experiment in bicarbonate free medium is shown. A detailed description of the determination of the CER in bicarbonate buffered medium will be given elsewhere.

  • Lethal events during gas sparging in Animal Cell Culture.
    Biotechnology and Bioengineering, 1991
    Co-Authors: I. Jöbses, D. Martens, Johannes Tramper
    Abstract:

    The lethal effects of gas sparging on hybridoma Cells obtained from a chemostat Culture were examined in a bubble column. Experiments were performed to identify and quantify the main hazardous event: bubble formation, bubble rising, or bubble breakup. The results indicate that bubble breakup is the main cause of Cell death. The protective activity of the surfactant Pluronic F68 against sparging seems to result from a direct interaction with the Cells rather than influencing bubble-liquid interface properties.

R. E. Spier - One of the best experts on this subject based on the ideXlab platform.

  • Oxygen transfer properties of bubbles in Animal Cell Culture media
    Biotechnology and bioengineering, 1992
    Co-Authors: S. Zhang, A. Handa-corrigan, R. E. Spier
    Abstract:

    Oxygen transfer rates were determined in a bubble aerated Animal Cell bioreactor. It was found that the oxygen transfer rates increased in the following order: large bubbles ( approximately 5 mm diameter) < intermediate bubbles ( approximately 1 mm diameter) < micron-sized bubbles ( approximately 100 microm diameter). Under certain conditions, the micron-sized bubbles were capable of achieving oxygen transfer rate up to 100 h(-1), a 10-20-fold higher transfer rate than the large bubbles. The effects of medium composition on oxygen transfer rates were different for the three ranges of bubbles studied. For the large bubbles, oxygen transfer rates decreased with increasing medium complexity. The lowest oxygen transfer rate was found in new-born calf serum (NBCS) and/or Pluronic F-68 supplemented media. For the intermediate and micron-sized bubbles, supplementation with NBCS into the Culture media resulted in decreased oxygen transfer rate. However, further supplementation with Pluronic F-68 enhanced oxygen transfer rate greatly for both types of bubbles. The highest oxygen transfer rate was found for micron-sized bubbles in Pluronic F-68 supplemented media containing antifoam agent and NBCS.

  • Oxygen transfer properties of bubbles in Animal Cell Culture media
    Biotechnology and bioengineering, 1992
    Co-Authors: S. Zhang, A. Handa-corrigan, R. E. Spier
    Abstract:

    Oxygen transfer rates were determined in a bubble aerated Animal Cell bioreactor. It was found that the oxygen transfer rates increased in the following order: large bubbles (≈5 mm diameter) < intermediate bubbles (≈1 mm diameter) < micron-sized bubbles (≈100 μm diameter). Under certain conditions, the micron-sized bubbles were capable of achieving oxygen transfer rate up to 100 h−1, a 10–20-fold higher transfer rate than the large bubbles. The effects of medium composition on oxygen transfer rates were different for the three ranges of bubbles studied. For the large bubbles, oxygen transfer rates decreased with increasing medium complexity. The lowest oxygen transfer rate was found in new-born calf serum (NBCS) and/or Pluronic F-68 supplemented media. For the intermediate and micron-sized bubbles, supplementation with NBCS into the Culture media resulted in decreased oxygen transfer rate. However, further supplementation with Pluronic F-68 enhanced oxygen transfer rate greatly for both types of bubbles. The highest oxygen transfer rate was found for micron-sized bubbles in Pluronic F-68 supplemented media containing antifoam agent and NBCS.

I. Jöbses - One of the best experts on this subject based on the ideXlab platform.

  • Lethal events during gas sparging in Animal Cell Culture.
    Biotechnology and Bioengineering, 1991
    Co-Authors: I. Jöbses, D. Martens, Johannes Tramper
    Abstract:

    The lethal effects of gas sparging on hybridoma Cells obtained from a chemostat Culture were examined in a bubble column. Experiments were performed to identify and quantify the main hazardous event: bubble formation, bubble rising, or bubble breakup. The results indicate that bubble breakup is the main cause of Cell death. The protective activity of the surfactant Pluronic F68 against sparging seems to result from a direct interaction with the Cells rather than influencing bubble-liquid interface properties.

Jianye Xia - One of the best experts on this subject based on the ideXlab platform.

  • novel scale up strategy based on three dimensional shear space for Animal Cell Culture
    Chemical Engineering Science, 2020
    Co-Authors: Xiaonuo Teng, Huadong Peng, Yingping Zhuang, Siliang Zhang, Jianye Xia
    Abstract:

    Abstract Animal Cell cultivations are widely used for producing antibodies, vaccines, and recombinant protein drugs. However, the extreme sensitivity of Animal Cells to hydrodynamic stress often hinders its scale-up in large-scale stirred tank bioreactors. This study introduced a new scale-up strategy based on three-dimensional (3D) shear space for large-scale Animal Cell Culture. First, the shear environments of bioreactors ranging from lab-scale (7.5 and 42 L) to industrial-scale (30, 90, 350, and 1000 L) were quantitatively analyzed through computational fluid dynamics (CFD) methods and successfully validated by particle image velocimetry (PIV) experiments. Moreover, the quantitative relationships between shear parameters (including shear rates in the impeller and tank zone, overall average shear rate, and maximum shear rate) and impeller tip velocity were established. In addition, a correlation analysis between shear-related parameters and viable Cell densities in Spodoptera frugiperda Sf9 cultivations indicated that shear rates in the impeller and tank zone, and the overall average shear rate were the three key shear parameters required for scale-up. Further, an optimized 3D operation space for shear rate was established according to the three key shear parameters obtained under preferable operation conditions in lab-scale bioreactors. Based on the results, agitation rates in large-scale bioreactors were determined using the proposed correlation. Ultimately, we achieved successful scale-up of Spodoptera frugiperda Sf9 in industrial bioreactors with volumes up to 1000 L using this strategy. Thus, this study introduces a highly efficient and economical scale-up strategy for shear-sensitive Cells.

John A. Frangos - One of the best experts on this subject based on the ideXlab platform.

  • Shear sensitivity in Animal Cell Culture.
    Current opinion in biotechnology, 1993
    Co-Authors: Keith J. Gooch, John A. Frangos
    Abstract:

    Over the past year, considerable progress has been made in understanding shear sensitivity in Animal Cell Culture as a result of extensive theoretical and experimental work. Here we review this progress, paying special attention to the physical and biological mechanisms by which mechanical forces act upon Cells, and the effects of such forces.