title: Metabolic engineering of Saccharomyces cerevisiae ethanol strains PE-2 and CAT-1 for efficient lignocellulosic fermentation.
abstract: In this work, Saccharomyces cerevisiae strains PE-2 and CAT-1, commonly used in the Brazilian fuel ethanol industry, were engineered for xylose fermentation, where the first fermented xylose faster than the latter, but also produced considerable amounts of xylitol. An engineered PE-2 strain (MEC1121) efficiently consumed xylose in presence of inhibitors both in synthetic and corn-cob hydrolysates. Interestingly, the S. cerevisiae MEC1121 consumed xylose and glucose simultaneously, while a CEN.PK based strain consumed glucose and xylose sequentially. Deletion of the aldose reductase GRE3 lowered xylitol production to undetectable levels and increased xylose consumption rate which led to higher final ethanol concentrations. Fermentation of corn-cob hydrolysate using this strain, MEC1133, resulted in an ethanol yield of 0.47 g/g of total sugars which is 92% of the theoretical yield.
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal. Electronic address: aloia@ceb.uminho.pt.
authors.forename: Aloia
authors.initials: A
authors.lastname: Romaní
authors.affiliation: CBMA - Center of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal. Electronic address: filipaabpereira@gmail.com.
authors.forename: Filipa
authors.initials: F
authors.lastname: Pereira
authors.affiliation: CBMA - Center of Molecular and Environmental Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal. Electronic address: bjorn_johansson@bio.uminho.pt.
authors.forename: Björn
authors.initials: B
authors.lastname: Johansson
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal. Electronic address: luciliad@deb.uminho.pt.
authors.forename: Lucília
authors.initials: L
authors.lastname: Domingues
mesh_terms: D061249:Batch Cell Culture Techniques; D050260:Carbohydrate Metabolism / Q000187:drug effects; D003470:Culture Media; D004587:Electrophoresis, Agar Gel; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D013464:Sulfuric Acids / Q000494:pharmacology; D014993:Xylitol / Q000096:biosynthesis; D014994:Xylose / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry
chemical_list: D003470:Culture Media; D013464:Sulfuric Acids; C036909:lignocellulose; D000431:Ethanol; D008031:Lignin; D014994:Xylose; D005947:Glucose; C033158:sulfuric acid; D005990:Glycerol; D014993:Xylitol
keywords: GRE3 aldose reductase; Industrial Saccharomyces cerevisiae; Second generation bio-ethanol; Simultaneous saccharification and co-fermentation (SSCF); Xylose fermentation