CO2 in large-scale and high-density CHO cell perfusion culture
CO2 in large-scale and high-density CHO cell perfusion culture
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DOI：
10.1007/bf00353925
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发表时间：
1996-01-01
期刊：
影响因子：
2.2
通讯作者：
Maiorella, BL
中科院分区：
文献类型：
--
作者：
Gray, DR;Chen, S;Maiorella, BL
当pCO（2）保持在30-76 mm Hg范围内时，CHO灌注培养反应器中的生产率最大化。较高水平的pCO（2）（>105 mm Hg）导致CHO细胞生长抑制和生产率显著降低。我们测量了灌注培养中CHO细胞的氧利用率和CO2产生率，分别为5.55 × 10（-17）mol cell（-1）sec（-1）和5.36 × 10（-17）mol cell（-1）sec（-1）。同时还建立了一种直接测定氧气和二氧化碳传质系数的简单方法。对于使用来自微孔玻璃料喷射器的0.002 VVM的纯氧喷射的500 L生物反应器，氧气和二氧化碳的总表观转移速率（k（L）a+k（A）A）分别为0.07264 min（-1）和0.002962 min（-1）。因此，虽然纯氧微泡的非常低的流速足以满足高达2.1 × 10（7）个细胞/mL的氧气供应要求，但低CO2去除效率将限制培养密度仅为2.4 × 10（6）个细胞/mL。开发了一个额外的模型来预测气泡尺寸对氧气和CO2传输速率的影响。如果在顶部空间和喷射中均使用纯氧，则可通过使用2-3 mm尺寸范围内的气泡来最小化喷射速率。对于该尺寸范围内的气泡，氧气供应与二氧化碳去除速率的比率与代谢氧利用率和二氧化碳产生速率的比率相匹配。在500 L反应器中使用该策略，我们预测溶解氧和CO2水平可以保持在支持10（7）个细胞/mL培养物的最大生产率（40% DO，76 mm Hg pCO（2））的范围内，最小喷射速率为0.006容器体积/分钟。
Productivity in a CHO perfusion culture reactor was maximized when pCO(2) was maintained in the range of 30-76 mm Hg. Higher levels of pCO(2) (>105 mm Hg) resulted in CHO cell growth inhibition and dramatic reduction in productivity. We measured the oxygen utilization and CO2 production rates for CHO cells in perfusion culture at 5.55 x 10(-17) mol cell(-1) sec(-1) and 5.36 x 10(-17) mel cell(-1) sec(-1) respectively. A simple method to directly measure the mass transfer coefficients for oxygen and carbon dioxide was also developed. For a 500 L bioreactor using pure oxygen sparge at 0.002 VVM from a microporous frit sparger, the overall apparent transfer rates (k(L)a+k(A)A) for oxygen and carbon dioxide were 0.07264 min(-1) and 0.002962 min(-1) respectively. Thus, while a very low flow rate of pure oxygen microbubbles would be adequate to meet oxygen supply requirements for up to 2.1 x 10(7) cells/mL, the low CO2 removal efficiency would limit culture density to only 2.4 x 10(6) cells/mL. An additional model was developed to predict the effect of bubble size on oxygen and CO2 transfer rates. If pure oxygen is used in both the headspace and sparge, then the sparging rate can be minimized by the use of bubbles in the size range of 2-3 mm. For bubbles in this size range, the ratio of oxygen supply to carbon dioxide removal rates is matched to the ratio of metabolic oxygen utilization and carbon dioxide generation rates. Using this strategy in the 500 L reactor, we predict that dissolved oxygen and CO2 levels can be maintained in the range to support maximum productivity (40% DO, 76 mm Hg pCO(2)) for a culture at 10(7) cells/mL, and with a minimum sparge rate of 0.006 vessel volumes per minute.