Print Email Facebook Twitter Evolutionary engineering in chemostat cultures for improved maltotriose fermentation kinetics in saccharomyces pastorianus lager brewing yeast Title Evolutionary engineering in chemostat cultures for improved maltotriose fermentation kinetics in saccharomyces pastorianus lager brewing yeast Author Brickwedde, A. (TU Delft BT/Industriele Microbiologie) van den Broek, M.A. (TU Delft BT/Industriele Microbiologie) Geertman, Jan Maarten A. (Heineken Supply Chain) Magalhães, Frederico (VTT Technical Research Center of Finland) Kuijpers, Niels G.A. (Heineken Supply Chain) Gibson, Brian (VTT Technical Research Center of Finland) Pronk, J.T. (TU Delft BT/Industriele Microbiologie) Daran, J.G. (TU Delft BT/Industriele Microbiologie) Date 2017 Abstract The lager brewing yeast Saccharomyces pastorianus, an interspecies hybrid of S. eubayanus and S. cerevisiae, ferments maltotriose, maltose, sucrose, glucose and fructose in wort to ethanol and carbon dioxide. Complete and timely conversion ("attenuation") of maltotriose by industrial S. pastorianus strains is a key requirement for process intensification. This study explores a new evolutionary engineering strategy for improving maltotriose fermentation kinetics. Prolonged carbon-limited, anaerobic chemostat cultivation of the reference strain S. pastorianus CBS1483 on a maltotriose-enriched sugar mixture was used to select for spontaneous mutants with improved affinity for maltotriose. Evolved populations exhibited an up to 5-fold lower residual maltotriose concentration and a higher ethanol concentration than the parental strain. Uptake studies with 14C-labeled sugars revealed an up to 4.75-fold higher transport capacity for maltotriose in evolved strains. In laboratory batch cultures on wort, evolved strains showed improved attenuation and higher ethanol concentrations. These improvements were also observed in pilot fermentations at 1,000-L scale with high-gravity wort. Although the evolved strain exhibited multiple chromosomal copy number changes, analysis of beer made from pilot fermentations showed no negative effects on flavor compound profiles. These results demonstrate the potential of evolutionary engineering for strain improvement of hybrid, alloploid brewing strains. Subject BrewingChemostatEvolutionary engineeringMaltoseMaltotriose consumption rateSacchromyces pastorianusTransportOA-Fund TU Delft To reference this document use: http://resolver.tudelft.nl/uuid:6feb309b-c3a3-4495-99c2-1dd4468efb84 DOI https://doi.org/10.3389/fmicb.2017.01690 ISSN 1664-302X Source Frontiers in Microbiology, 8 Part of collection Institutional Repository Document type journal article Rights © 2017 A. Brickwedde, M.A. van den Broek, Jan Maarten A. Geertman, Frederico Magalhães, Niels G.A. Kuijpers, Brian Gibson, J.T. Pronk, J.G. Daran Files PDF fmicb_08_01690.pdf 1.88 MB Close viewer /islandora/object/uuid:6feb309b-c3a3-4495-99c2-1dd4468efb84/datastream/OBJ/view