Food and Bioprocess Engineering Group, Wageningen Agricultural University, P.O. Box 8129, 6700 EV, Wageningen, the Netherlands.
Cytotechnology. 1996 Jan;20(1-3):231-8. doi: 10.1007/BF00350403.
It should be clear from the above that the calculations described here are at best rough estimations yielding order-of-magnitude values. Even though, the following general conclusions can be drawn. The gradients in stagnant layers surrounding the particles which are characteristic for animal-cell bioreactors are relatively small as compared to the gradients which can be expected in the bulk-liquid phases of the three bioreactors considered, in particular to the gradients in the stagnant layer surrounding the air bubbles. It can be concluded that under almost all circumstances gradients are likely to exist and can be very steep in larger vessels and in particular at high cell densities. The effects of gradients, however, are largely unknown; therefore research on the effects of gradients on specific and volumetric productivities and product quality seems to be an interesting area.
从上面可以清楚地看出，这里描述的计算充其量只是粗略的估计，只能得到数量级的值。即便如此，还是可以得出以下一般性结论。与在三种所考虑的生物反应器的主体液相中预期的梯度相比，在围绕颗粒的停滞层中的梯度在动物细胞生物反应器中是相对较小的，特别是与围绕气泡的停滞层中的梯度相比。可以得出结论，在几乎所有情况下，在较大的容器中，特别是在高细胞密度下，梯度很可能存在并且可能非常陡峭。然而，梯度的影响在很大程度上是未知的；因此，研究梯度对比生产率和总体生产率以及产品质量的影响似乎是一个有趣的领域。
