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Feeding lactate for CHO cell culture processes: Impact on culture metabolism and performance
Author(s) -
Li Jincai,
Wong Chun Loong,
Vijayasankaran Natarajan,
Hudson Terry,
Amanullah Ashraf
Publication year - 2012
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.24389
Subject(s) - lactic acid , biochemistry , catabolism , metabolism , biology , pyruvic acid , lactate dehydrogenase , sodium lactate , glycolysis , chemistry , bacteria , enzyme , genetics , organic chemistry , sodium
Lactate has long been regarded as one of the key metabolites of mammalian cell cultures. High levels of lactate have clear negative impacts on cell culture processes, and therefore, a great amount of efforts have been made to reduce lactate accumulation and/or to induce lactate consumption in the later stage of cultures. However, there is virtually no report on the impact of lactate depletion after initial accumulation. In this work, we observed that glucose uptake rate dropped over 50% at the onset of lactate consumption, and that catabolism of alanine due to lactate depletion led to ammonium accumulation. We explored the impact of feeding lactate as well as pyruvate to the cultures. In particular, a strategy was employed where CO 2 was replaced by lactic acid for culture pH control, which enabled automatic lactate feeding. The results demonstrated that lactate or pyruvate can serve as an alternative or even preferred carbon source during certain stage of the culture in the presence of glucose, and that by feeding lactate or pyruvate, very low levels of ammonia can be achieved throughout the culture. In addition, low levels of pCO 2 were also maintained in these cultures. This was in strong contrast to the control cultures where lactate was depleted during the culture, and ammonia and pCO 2 build‐up were significant. Culture growth and productivity were similar between the control and lactate‐fed cultures, as well as various product quality attributes. To our knowledge, this work represents the first comprehensive study on lactate depletion and offers a simple yet effective strategy to overcome ammonia and pCO 2 accumulation that could arise in certain cultures due to early depletion of lactate. Biotechnol. Bioeng. 2012; 109:1173–1186. © 2011 Wiley Periodicals, Inc.