A new model of uptake of multiple sugars by S. cerevisiae

Abstract

Carrying on from our work with yeast in batch culture with mixed substrates of glucose and fructose, a model developed previously was modified to incorporate firstly the use of sucrose as substrate and secondly the ability to simulate continuous culture. Experiments using sucrose as the limiting substrate were simulated based on sugar uptake, biomass and ethanol production, carbon dioxide production and oxygen consumption. The new sugar uptake models were able to successfully simulate these experiments. On the basis of these experiments there is a strong suggestion that a proportion of the sucrose utilised is transported into the cell rather than hydrolysed prior to entry. Continuous culture experiments were also simulated by adapting the modelling program into the format of a multiple differential equation problem solver called SPEEDUP.