Damage mechanisms of suspended animal cells in agitated bioreactors with and without bubble entrainment

Authors

  • Kurt T. Kunas,

    1. Department of Chemical Engineering, Rice University, P.O. Box 1892, Houston, Texas 77251-1892
    Search for more papers by this author
  • Eleftherios T. Papoutsakis

    Corresponding author
    1. Department of Chemical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3120
    • Department of Chemical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3120
    Search for more papers by this author

Abstract

We show that when freely suspended hybridoma cells are cultured in an agitated bioreactor, two fluid-mechanical mechanisms can cause cell damage and growth retardation. The first is present only when there is a gas phase, and is associated with vortex formation accompanied by bubble entrainment and breakup. In the absence of a vortex and bubble entrainment, cells can be damaged only at very high agitation rates, above approximately 700 rpm, by stresses in the bulk turbulent liquid. Cell damage then correlates with Kolmogorov eddy sizes similar to or smaller than the cell size. In the absence of a vortex, the entrainment and motion of very fine bubbles cause no growth retardation even at agitation rates as high as 600 rpm.

Ancillary