Genome-scale metabolic models reveal determinants of phenotypic differences in non-Saccharomyces yeasts

Abstract

AbstractBackgroundUse of alternative non-Saccharomycesyeasts in wine and beer brewing has gained more attention the recent years. This is both due to the desire to obtain a wider variety of flavours in the product and to reduce the final alcohol content. Given the metabolic differences between the yeast species, we wanted to account for some of the differences by usingin silicomodels.ResultsWe created and studied genome-scale metabolic models of five different non-Saccharomycesspecies using an automated processes. These were:Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora osmophilaandKluyveromyces lactis. Using the models, we predicted thatM. pulcherrima, when compared to the other species, conducts more respiration and thus produces less fermentation products, a finding which agrees with experimental data. Complex I of the electron transport chain was to be present inM. pulcherrima, but absent in the others. The predicted importance of Complex I was diminished when we incorporated constraints on the amount of enzymatic protein, as this shifts the metabolism towards fermentation.ConclusionsOur results suggest that Complex I in the electron transport chain is a key differentiator betweenMetschnikowia pulcherrimaand the other yeasts considered. Yet, more annotations and experimental data have the potential to improve model quality in order to increase fidelity and confidence in these results. Further experiments should be conducted to confirm thein vivoeffect of Complex I inM. pulcherrimaand its respiratory metabolism.