Large‐scale bioreactors for the production of monoclonal antibodies reach volumes of up to 25 000 L. With increasing bioreactor size, mixing is however affected negatively, resulting in the formation of gradients throughout the reactor. These gradients can adversely affect process performance at large scale. Since mammalian cells are sensitive to changes in pH, this study investigated the effects of pH gradients on process performance. A 2‐Compartment System was established for this purpose to expose only a fraction of the cell population to pH excursions and thereby mimicking a large‐scale bioreactor. Cells were exposed to repeated pH amplitudes of 0.4 units (pH 7.3), which resulted in decreased viable cell counts, as well as the inhibition of the lactate metabolic shift. These effects were furthermore accompanied by increased absolute lactate levels. Continuous assessment of molecular attributes of the expressed target protein revealed that subunit assembly or N‐glycosylation patterns were only slightly influenced by the pH excursions. The exposure of more cells to the same pH amplitudes further impaired process performance, indicating this is an important factor, which influences the impact of pH inhomogeneity. This knowledge can aid in the design of pH control strategies to minimize the effects of pH inhomogeneity in large‐scale bioreactors.

中文翻译：

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开发、表征和应用 2 室系统来研究大规模 CHO 工艺中 pH 不均匀性的影响


用于生产单克隆抗体的大型生物反应器的体积高达 25000 L。然而，随着生物反应器尺寸的增加，混合会受到负面影响，导致整个反应器中形成梯度。这些梯度会对大规模的过程性能产生不利影响。由于哺乳动物细胞对 pH 值的变化很敏感，因此本研究调查了 pH 梯度对工艺性能的影响。为此目的建立了一个 2 室系统，仅将一小部分细胞群暴露于 pH 波动中，从而模拟大型生物反应器。细胞反复暴露于 0.4 个单位 (pH 7.3) 的 pH 值，导致活细胞计数减少，并抑制乳酸代谢变化。此外，这些效应还伴随着绝对乳酸水平的增加。对表达的靶蛋白的分子属性的连续评估表明，亚基组装或 N-糖基化模式仅受 pH 偏移的轻微影响。更多细胞暴露于相同的 pH 值会进一步损害工艺性能，表明这是影响 pH 不均匀性的一个重要因素。这些知识可以帮助设计 pH 控制策略，以尽量减少大型生物反应器中 pH 不均匀性的影响。