Co-utilization of L-arabinose and D-xylose by laboratory and industrial <it>Saccharomyces cerevisiae </it>strains

• Main Authors: Boles Eckhard, Hahn-Hägerdal Bärbel, Wiedemann Beate, Karhumaa Kaisa, Gorwa-Grauslund Marie-F
• Format: Article
• Language: English
• Published: BMC 2006-04-01
• Series: Microbial Cell Factories
• Online Access: http://www.microbialcellfactories.com/content/5/1/18

<p>Abstract</p> <p>Background</p> <p>Fermentation of lignocellulosic biomass is an attractive alternative for the production of bioethanol. Traditionally, the yeast <it>Saccharomyces cerevisiae </it>is used in industrial ethanol fermentations. However, <it>S. cerevisiae </it>is naturally not able to ferment the pentose sugars D-xylose and L-arabinose, which are present in high amounts in lignocellulosic raw materials.</p> <p>Results</p> <p>We describe the engineering of laboratory and industrial <it>S. cerevisiae </it>strains to co-ferment the pentose sugars D-xylose and L-arabinose. Introduction of a fungal xylose and a bacterial arabinose pathway resulted in strains able to grow on both pentose sugars. Introduction of a xylose pathway into an arabinose-fermenting laboratory strain resulted in nearly complete conversion of arabinose into arabitol due to the L-arabinose reductase activity of the xylose reductase. The industrial strain displayed lower arabitol yield and increased ethanol yield from xylose and arabinose.</p> <p>Conclusion</p> <p>Our work demonstrates simultaneous co-utilization of xylose and arabinose in recombinant strains of <it>S. cerevisiae</it>. In addition, the co-utilization of arabinose together with xylose significantly reduced formation of the by-product xylitol, which contributed to improved ethanol production.</p>