Abstract
An estimation is made of oxygen gradients in animal-cell bioreactors, using straightforward engineering calculations. Three types of bioreactor are considered: stirred vessel, bubble column and air lift, of sizes between 0.01 and 10 m3. First, the gradient is estimated in the stagnant layer surrounding a cell (15 μm), a microcarrier (185 μm) with 300 cells attached to it, a macroporous support (1.25 mm) containing 185,00 cells and one (6 mm) containing 4.25 million cells. It is assumed that oxygen consumption is 10−16 mole O2·cell−1·s−1, while mass transfer coefficients are obtained from Sherwood relations. Circulation and liquid-retention times of the bioreactors are compared with the oxygen-exhaust times of suspensions with 1012, 1013 and 1014 cells/m3 to estimate if oxygen gradients are likely to exist in the bulk-liquid phase. Finally, the gradient in the liquid film surrounding air bubbles is estimated using k l A-values obtained from empirical correlations. It is clear from all these estimations that in many situations severe gradients can be expected. The question remains, however, whether gradients should be avoided as much as possible, or may be tolerated to a certain extent or even created on purpose because of possible beneficial effects.
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References
Aunins JG & Henzler H-J (1993) Aeration in cell culture bioreactors. In: Stephanopoulos G (ed.) Biotechnology. Vol. 3. Bioprocessing (pp. 219–280) VCH, Weinheim.
Bailey JE & Ollis DF (1986) Biochemical Engineering Fundamentals. McGraw-Hill, Singapore.
Sänger P & Deckwer WD (1981) Liquid-solid mass transfer in aerated suspension. Chem Eng. J. 22: 179–186.
Sano Y, Yamaguchi N & Adachi T (1974) Mass transfer coefficients for suspended particles in agitated vessels and bubble columns. J. Chem. Eng. Japan 7: 225.
Spier RE & Griffiths B (1984) An examination of the data and concepts germane to the oxygenation of cultured animal cells. Dev. Biol. Stand. 55: 81–92.
Van't Riet K & Tramper J (1991) Basic Bioreactor Design. Marcel Dekker, New York.
Wijffels RH, De Gooijer CD, Schepers AW, Beuling EE, Mallée LR & Tramper J (1994) Growth of immobilizedNitrosomonas europaea: implementation of diffusion limitation over microcolonies (submitted).
Wijffels RH, De Gooijer CD, Kortekaas S & Tramper J (1991) Growth and substrate consumption ofNitrobacter agilis cells immobilized in carrageenan: Part 2. Model evaluation. Biotech. Bioeng. 38: 232–240.
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Tramper, J. Oxygen gradients in animal-cell bioreactors. Cytotechnology 18, 27–34 (1995). https://doi.org/10.1007/BF00744317
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DOI: https://doi.org/10.1007/BF00744317