Determination of in vivo oxygen uptake and carbon dioxide evolution rates from off-gas measurements under highly dynamic conditions

• Published in: Biotechnology and bioengineering 2003-02, Vol.81 (4), p.448-458
• Main Authors: Wu, L., Lange, H. C., van Gulik, W. M., Heijnen, J. J.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Bioreactors; Biotechnology; Carbon Dioxide - analysis; Carbon Dioxide - metabolism; carbon dioxide evolution rate; Cell Culture Techniques - methods; Computer Simulation; Culture Media - pharmacology; Equipment Design; Ethanol - administration & dosage; Fundamental and applied biological sciences. Psychology; Glucose - administration & dosage; in vivo kinetics; Linear Models; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Models, Biological; Oxygen - analysis; Oxygen - metabolism; Oxygen Consumption; oxygen uptake rate; pulse experiment; Saccharomyces cerevisiae; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - metabolism; system identification
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.10480

In vivo kinetics of Saccharomyces cerevisiae are studied, in a time window of 150 s, by analyzing the response of O2 and CO2 in the fermentor off‐gas after perturbation of chemostat cultures by metabolite pulses. Here, a new mathematical method is presented for the estimation of the in vivo oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER) directly from the off‐gas data in such perturbation experiments. The mathematical construction allows effective elimination of delay and distortion in the off‐gas measurement signal under highly dynamic conditions. A black box model for the fermentor off‐gas system is first obtained by system identification, followed by the construction of an optimal linear filter, based on the identified off‐gas model. The method is applied to glucose and ethanol pulses performed on chemostat cultures of S. cerevisiae. The estimated OUR is shown to be consistent with the independent dissolved oxygen measurement. The estimated in vivo OUR and CER provide valuable insights into the complex dynamic behavior of yeast and are essential for the establishment and validation of in vivo kinetic models of primary metabolism. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 448–458, 2003.