Bioprocess and Biosystems Engineering

, Volume 41, Issue 12, pp 1731–1741 | Cite as

pH excursions impact CHO cell culture performance and antibody N-linked glycosylation

  • Rubin Jiang
  • Hao Chen
  • Sen XuEmail author
Research Paper


pH excursions exist due to frequent base addition and environmental heterogeneity in large-scale bioreactors. Such excursions could lead to suboptimal culture performance. Here we investigated the impact of pH excursions on cell culture performance and N-linked glycosylation for three MAb-producing Chinese hamster ovary cell lines. Frequent pH excursions were introduced by bolus base addition (in total 2–6% of initial volume, fixed bolus addition distributed from day 2 to 8) into small-scale bioreactors. Base addition led to increase in osmolality, pCO2, and lactate production. Lactate production increase was mainly caused by increased culture pH due to base addition, and bolus addition led to higher glucose and lactate metabolic rates than continuous addition. For the three cell lines studied, antibody galactosylation increased with the increase in cultivating pH, correlating to the decrease in cell-specific productivity. Interestingly, pH excursions led to significantly higher galactosylation for one cell line, which also had a higher response to different cultivating pHs. On the other hand, there was no such substantial impact of pH excursions on galactosylation for the other two cell lines, both of which also had minimal response to cultivating pH. This suggests that the impact of pH excursions on antibody N-linked glycosylation is cell line specific and is closely related to cell line response to cultivating pH.


Heterogeneity Lactate Mixing Quality attributes Scale-up/scale-down 



We thank the Bioprocess Technical Operations group for inoculum and media preparation, Elizabeth Valente, Illysa Hom, Justin Miller, and Michael Rauscher for in-process purification and analytics support, Sonja Battle and Jaymim Patel for N-glycan analysis. We would also like to thank Gregg Nyberg and John Bowers for their constructive feedback.

Supplementary material

449_2018_1996_MOESM1_ESM.doc (348 kb)
Supplementary material 1 (DOC 348 KB)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Biologics Process Research and Development, Process Research and DevelopmentMerck & Co., Inc.KenilworthUSA
  2. 2.Cell & Viral Drug Substance, Global Vaccines Technical Research & Development, GlaxoSmithKline VaccinesRixensartBelgium

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