Dynamic metabolic networks in E. coli fermentations (FWO)

Dynamic metabolic networks to elucidate the effects induced by oscillating environmental conditions in Ecoli fermentions

When environmental conditions are oscillated in a certain way, cells will start `resonating' and will produce more fermentation product, in comparison with classic chemostat operation. As an example, the repression of the enzymes by glucose, playing a role in the Krebs cycle, is mentioned. When the fermentation is started at low glucose concentrations, high expression of the Krebs cycle enzymes is observed, but biomass production remains at a low level. Raising the glucose concentration results in an increasing biomass production, but the production of enzymes of the Krebs cycle will now be repressed by high substrate concentrations. When these enzymatic concentrations have decreased in such a way that the reaction products, resulting from glycolysis, can not be converted anymore, the glucose concentration is again decreased. Production of the enzymes of the Krebs cycle will be restarted, because this decrease cancels the glucose repression. Meanwhile, biomass production will proceed, using the accumulated glycolysis products. When these glycolysis products get exhausted, glucose concentration is increased again. By carefully choosing the moments in time when the glucose concentration is altered, the cell can be brought into a `resonance' state. In this way, biomass production can be increased and overflow metabolism will be avoided.

Project duration: 2004-01-01 - 2007-12-31

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Karl Rumbold
Department of Applied Mathematics, Biometrics and Process Control
Coupure Links 653
9000 Gent
Tel: 09/ 264 61 96
Fax: 09/ 264 62 20
Email: Karl.Rumbold@Ugent.be

Last update: 01 december 2008, webmaster@biomath.ugent.be

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