title: In silico aided metabolic engineering of Saccharomyces cerevisiae for improved bioethanol production.
abstract: In silico genome-scale cell models are promising tools for accelerating the design of cells with improved and desired properties. We demonstrated this by using a genome-scale reconstructed metabolic network of Saccharomyces cerevisiae to score a number of strategies for metabolic engineering of the redox metabolism that will lead to decreased glycerol and increased ethanol yields on glucose under anaerobic conditions. The best-scored strategies were predicted to completely eliminate formation of glycerol and increase ethanol yield with 10%. We successfully pursued one of the best strategies by expressing a non-phosphorylating, NADP(+)-dependent glyceraldehyde-3-phosphate dehydrogenase in S. cerevisiae. The resulting strain had a 40% lower glycerol yield on glucose while the ethanol yield increased with 3% without affecting the maximum specific growth rate. Similarly, expression of GAPN in a strain harbouring xylose reductase and xylitol dehydrogenase led to an improvement in ethanol yield by up to 25% on xylose/glucose mixtures.
authors.affiliation: Center for Microbial Biotechnology, BioCentrum-DTU, Building 223, Technical University of Denmark, DK-2800 Kgs, Lyngby, Denmark.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Bro
authors.forename: Birgitte
authors.initials: B
authors.lastname: Regenberg
authors.forename: Jochen
authors.initials: J
authors.lastname: Förster
authors.forename: Jens
authors.initials: J
authors.lastname: Nielsen
mesh_terms: D003198:Computer Simulation; D000431:Ethanol / Q000378:metabolism*; D005786:Gene Expression Regulation; D024861:Genetic Enhancement / Q000379:methods; D024601:Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+) / Q000235:genetics / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D008954:Models, Biological; D010084:Oxidation-Reduction; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; D024601:Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+); D005990:Glycerol