title: Fermentation performance of engineered and evolved xylose-fermenting Saccharomyces cerevisiae strains.
abstract: Lignocellulose hydrolysate is an abundant substrate for bioethanol production. The ideal microorganism for such a fermentation process should combine rapid and efficient conversion of the available carbon sources to ethanol with high tolerance to ethanol and to inhibitory components in the hydrolysate. A particular biological problem are the pentoses, which are not naturally metabolized by the main industrial ethanol producer Saccharomyces cerevisiae. Several recombinant, mutated, and evolved xylose fermenting S. cerevisiae strains have been developed recently. We compare here the fermentation performance and robustness of eight recombinant strains and two evolved populations on glucose/xylose mixtures in defined and lignocellulose hydrolysate-containing medium. Generally, the polyploid industrial strains depleted xylose faster and were more resistant to the hydrolysate than the laboratory strains. The industrial strains accumulated, however, up to 30% more xylitol and therefore produced less ethanol than the haploid strains. The three most attractive strains were the mutated and selected, extremely rapid xylose consumer TMB3400, the evolved C5 strain with the highest achieved ethanol titer, and the engineered industrial F12 strain with by far the highest robustness to the lignocellulosic hydrolysate.
authors.affiliation: Institute of Biotechnology, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Sonderegger
authors.forename: Marie
authors.initials: M
authors.lastname: Jeppsson
authors.forename: Christer
authors.initials: C
authors.lastname: Larsson
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Gorwa-Grauslund
authors.forename: Eckhard
authors.initials: E
authors.lastname: Boles
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Olsson
authors.forename: Isabel
authors.initials: I
authors.lastname: Spencer-Martins
authors.forename: Bärbel
authors.initials: B
authors.lastname: Hahn-Hägerdal
authors.forename: Uwe
authors.initials: U
authors.lastname: Sauer
mesh_terms: D002482:Cellulose / Q000378:metabolism*; D004171:Diploidy; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development*; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000235:genetics / Q000378:metabolism*
chemical_list: C036909:lignocellulose; D000431:Ethanol; D002482:Cellulose; D008031:Lignin; D014994:Xylose; D014993:Xylitol