Stoichiometric analysis of animal cell growth and its application in medium design

Abstract

Animal cell cultivation in vitro has been studied for more than 40 years. However, the culture medium composition has not been designed on the basis of the stoichiometric nutritional demands for animal cell growth. In this article, a model was developed to study the stoichiometric demands for nutrients (including glucose, 20 amino acids, and 10 vitamins)for the synthesis of cell mass and product. The coefficients for these nutrients in the stoichiometric equation governing animal cell growth were determined based on cell composition. In addition, a detailed analysis of the nutrients' roles in the synthesis of cell mass and product was also performed. Applications of the stoichiometric analysis in animal cell cultivation, such as culture medium design, supplemental medium formulation, and feeding strategy will also be discussed. The stoichiometric analysis can be potentially employed to analyze results from animal cell cultures, to improve the performance of culture processes, and to design new process rationally. It can also help to provide a better understanding of animal cell metabolism. Simplifications on the cellular energy metabolism were made in order to simplify the model and to provide the preliminary bases to test the process performance. However, this could introduce inaccuracies for the model and results in errors in the calculations of glucose and glutamine concentrations when employed in medium design. (c) 1994 John Wiley & Sons, Inc.

Improved extracellular transferase enzyme production by Aspergillus foetidus for synthesis of isooligosaccharides

“…Earlier reports of Zhu et al [23] using stoichiometric analysis optimization method developed by Xie and Wang [24] had indicated that certain amino acids were required for enhanced production of transglutaminase enzyme. As it would not be possible to add these amino acids in pure form in a practical system, ®nding a supplementary nitrogen source rich in amino acids composition will be more economic.…”

Specific heat flow rate: An on-line monitor and potential control variable of specific metabolic rate in animal cell culture that combines microcalorimetry with dielectric spectroscopy

“…In the second phase, from 40 to 75 h, the specific heat flow rate showed a continuous decline coincident with the fact that the concentrations of glucose and glutamine in the medium decreased to such an extent that the amounts of them were minimal at 75 h. When considering this, it is important to know that the K m for glutamine in cell growth is between 0.09 and 0.53 mM, depending on cell type (Jeong and Wang, 1995;Xie and Wang, 1994) and that of glucose, 0.5 to 1.5 mM (Xie and Wang, 1994). For Monod-type substrate effects, this implies that for at least the majority of the growth phase of the CHO 320 cells, changes in the reaction stoichiometry were due to alterations in cellular metabolism rather than to the kinetics of substrate uptake.…”

High cell density and high monoclonal antibody production through medium design and rational control in a bioreactor

“…To meet the requirement of essential nutrients for growth and to prevent their depletion, the stoichiometric demands of glucose, amino acids, and vitamins were studied (Xie and Wang, 1994b). Reduction of ammonia and lactate formation was achieved by feeding the supplemental medium according to the needs for cell growth and product formation (Xie and Wang, 1994a,c).…”