Department of Chemical, Biological and Environmental Engineering, Autonomous University of Barcelona, 08193 Cerdanyola del Vallès, Spain.
Department of Biotechnology, Farmhispania SA, Montmeló, Spain.
J Biotechnol. 2018 Dec 10;287:68-73. doi: 10.1016/j.jbiotec.2018.10.005. Epub 2018 Oct 21.
Although pH control at physiological levels is generally considered as the optimal culture condition, in some cases other strategies should be taken into account for their beneficial effects on process performance. pH and CO levels are chemical variables that have a major impact in cell growth and product titers in cell culture since their effect on key metabolic routes. HEK293 cells expressing recombinant hIFNγ showed different metabolic behavior when cultured in shake flask compared to pH-controlled bioreactors, in which a decrease in cell density and product titer were observed. This yield loss observed in bioreactor cultures could be reverted by adding 1% CO to air inlet flow in a non-controlled pH bioprocess. With this strategy, a significant outcome of 4-fold increase in terms of maximum cell density and 2-fold increase in volumetric concentration of recombinant protein (hIFNγ) when compared to the pH-controlled culture in bioreactor (standard culture conditions) has been obtained. Results evidenced the importance of pH and CO concentration in this case, in order to reproduce the behavior observed in optimization experiments performed in shake flasks. Thus, it was demonstrated that not always constant controlled variable setpoint (like pH or CO addition) becomes the best bioprocess performance strategy.
虽然将 pH 值控制在生理水平通常被认为是最佳的培养条件，但在某些情况下，为了获得对工艺性能的有益影响，应该考虑其他策略。pH 值和 CO 水平是化学变量，它们对细胞生长和细胞培养中的产物滴度有重大影响，因为它们对关键代谢途径有影响。与 pH 控制的生物反应器相比，在摇瓶中培养表达重组 hIFNγ 的 HEK293 细胞时，表现出不同的代谢行为，在生物反应器培养中观察到细胞密度和产物滴度下降。在非 pH 控制的生物过程中，向空气入口流中添加 1% CO 可以逆转生物反应器培养中观察到的这种产率损失。通过这种策略，与生物反应器中的 pH 控制培养（标准培养条件）相比，在最大细胞密度方面获得了 4 倍的显著提高，在重组蛋白（hIFNγ）的体积浓度方面获得了 2 倍的提高。结果表明在这种情况下，pH 值和 CO 浓度的重要性，以重现在摇瓶中进行的优化实验中观察到的行为。因此，证明了并非总是恒定的控制变量设定值（如 pH 值或 CO 添加）成为最佳生物过程性能策略。
