On-line fermentation gas analysis: Error analysis and application of mass spectrometry

Heinzle, Elmar; Oeggerli, A.; Dettwiler, B.

doi:10.1016/s0003-2670(00)80528-0

Cited by 62 publications

(35 citation statements)

References 7 publications

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“…• Mass balances, including calculations for water stripping (Heinzle et al, 1990), ethanol stripping (Duboc and von Stockar, 1998), base addition, and sample withdrawal of cell free permeate.…”

Section: Methods Implementationmentioning

confidence: 99%

On‐line stoichiometry and identification of metabolic state under dynamic process conditions

Herwig

Marison

Stockar

2001

Biotech & Bioengineering

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A method for the on-line calculation of conversion rates and yield coefficients under dynamic process conditions was developed. The method is based on cumulated mass balances using a moving average method. Elemental balances were used to test the measured cumulated quantities for gross errors and inappropriate stoichiometry definition followed by data reconciliation and estimation of non-measured conversion rates, using a bioprocess set-up including multiple on-line analysis techniques. The quantitative potential of the proposed method is demonstrated by executing transient experiments in aerobic cultures of Saccharomyces cerevisiae on glucose. Rates and yield coefficients could be consistently quantified in shift-up, shift-down, and accelerostat experiments. The method shows the capability to describe quantitatively transient changes in metabolism including uncoupling of catabolism and anabolism, also for the case when multiple components of metabolism are not measured. The validity of the experiment can be evaluated on-line. Additionally, the method detects with high sensitivity inappropriate stoichiometry definition, such as a change in state of metabolism. It was shown that concentration values can be misleading for the identification of the metabolic state. In contrast, the proposed method provides a clear picture of the metabolic state and new physiological regulations could be revealed. Hence, the novelty of the proposed method is the on-line availability of consistent stoichiometric coefficients allowing a significant speed up in strain characterization and bioprocess development using minimal knowledge of the metabolism. Additionally, it opens up the use of transient experiments for physiological studies.

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Section: Methods Implementationmentioning

confidence: 99%

On‐line stoichiometry and identification of metabolic state under dynamic process conditions

Herwig

Marison

Stockar

2001

Biotech & Bioengineering

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“…The number of these bioreactor-related applications has been increasing steadily (Lloyd et al, 1985;Heinzle et al, 1990;. The usual procedure is to monitor the production (or consumption) of gaseous (Arcangeli et al, 1996) or dissolved organic compounds (Schou et al, 1997), which can include various organic acids and other semivolatiles .…”

Section: A Bioreactorsmentioning

confidence: 99%

Membrane introduction Mass Spectrometry: Trends and applications

Johnson

Cooks

Allen

et al. 2000

Mass Spectrom. Rev.

238

182

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“…Carbon dioxide in the exhaust gas was determined using an infra-red CO 2 analyzer (Servomex). The gas analyzers were calibrated automatically every 24 h by means of a two-point calibration using gases of known composition, and the oxygen uptake and carbon dioxide evolution rates were determined and corrected for residual water content (Heinzle et al, 1990).…”

Section: Bioreactor Culturesmentioning

confidence: 99%

Quantitative analysis of the regulation scheme of invertase expression in Saccharomyces cerevisiae

Herwig

Doerries

Marison

et al. 2001

Biotech & Bioengineering

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In Saccharomyces cerevisiae, the expression of invertase, which is the hydrolyzing enzyme of sucrose, is controlled by the presence of monosaccharides, such as glucose and fructose, and referred to as carbon catabolite repression. To date, efforts have been made to identify the mechanism by which cells sense extracellular monosaccharide concentrations and trigger the genes involved in the repression pathway. The aim of the present work was to quantitatively investigate the cellular regulation of invertase expression in the wild-type strain S. cerevisiae CEN.PK113-7D during batch growth containing mixed sugar substrates under different initial conditions. Because of the high frequency and accurate online analysis of multiple components, a tight control of invertase expression could be observed, and threshold concentrations of the monosaccharides for derepression could be determined to 0.5 gl(-1) for glucose and 2 gl(-1) for fructose. Also, the existence of a hitherto undescribed regulatory state, in which cells regulate invertase expression very precisely and operate over long periods at monosaccharide concentrations lower than the above thresholds, could be demonstrated. All experimental observations could be summarized in a formulation of the cellular regulation scheme of invertase expression. A simple kinetic model could show that the regulation scheme explains the observed behavior very well. Additionally, the model was able to explain consequences of the regulation on the global metabolism.

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On-line fermentation gas analysis: Error analysis and application of mass spectrometry

Cited by 62 publications

References 7 publications

On‐line stoichiometry and identification of metabolic state under dynamic process conditions

On‐line stoichiometry and identification of metabolic state under dynamic process conditions

Membrane introduction Mass Spectrometry: Trends and applications

Quantitative analysis of the regulation scheme of invertase expression in Saccharomyces cerevisiae

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