A biochemically structured model for Saccharomyces cerevisiae

• Published in: Journal of biotechnology Vol. 88; no. 3; pp. 205 - 221
• Main Authors: Lei, Frede, Rotbøll, Morten, Jørgensen, Sten Bay
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 12.07.2001; Amsterdam Elsevier; New York, NY
• Subjects: Aerobiosis; Biological and medical sciences; Biological Transport, Active; Biotechnology; Ethanol - metabolism; Fermentation; Fundamental and applied biological sciences. Psychology; Glucose - metabolism; Kinetics; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Models, Biological; Multiple steady-states; Oxidation-Reduction; Saccharomyces cerevisiae; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Structured modelling; Saccharomyces cerevisiae; Multiple steady-states; Structured modelling; Microorganism growth; Yeast; Ethanol; Aerobe; Glucose; Metabolism; Steady state; Fungi; Kinetic model; Structured model; Microorganism culture; Ascomycetes; Thallophyta
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/S0168-1656(01)00269-3

A biochemically structured model for the aerobic growth of Saccharomyces cerevisiae on glucose and ethanol is presented. The model focuses on the pyruvate and acetaldehyde branch points where overflow metabolism occurs when the growth changes from oxidative to oxido-reductive. The model is designed to describe the onset of aerobic alcoholic fermentation during steady-state as well as under dynamical conditions, by triggering an increase in the glycolytic flux using a key signalling component which is assumed to be closely related to acetaldehyde. An investigation of the modelled process dynamics in a continuous cultivation revealed multiple steady states in a region of dilution rates around the transition between oxidative and oxido-reductive growth. A bifurcation analysis using the two external variables, the dilution rate, D, and the inlet concentration of glucose, S f, as parameters, showed that a fold bifurcation occurs close to the critical dilution rate resulting in multiple steady-states. The region of dilution rates within which multiple steady states may occur depends strongly on the substrate feed concentration. Consequently a single steady state may prevail at low feed concentrations, whereas multiple steady states may occur over a relatively wide range of dilution rates at higher feed concentrations.