Construction of efficient xylose-fermenting Saccharomyces cerevisiae through a synthetic isozyme system of xylose reductase from Scheffersomyces stipitis

• Published in: Bioresource technology 2017-10, Vol.241, p.88-94
• Main Authors: Jo, Jung-Hyun, Park, Yong-Cheol, Jin, Yong-Su, Seo, Jin-Ho
• Format: Article
• Language: English
• Subjects: Aldehyde Reductase; Cellulosic ethanol; Ethanol; Fermentation; Isoenzymes; Saccharomyces cerevisiae; Synthetic isozyme system; Xylose; Xylose reductase
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2017.05.091

•The engineered S. cerevisiae strain having both wild XR and mutant XR was constructed.•The XR based isozyme was used to extend cofactor availability.•Coexpressing of wild XR and mutant XR improved the bioethanol productivity and yield.•The ethanol productivity of 1.85g/L·h and yield of 0.427g/g were obtained. Engineered Saccharomyces cerevisiae has been used for ethanol production from xylose, the abundant sugar in lignocellulosic hydrolyzates. Development of engineered S. cerevisiae able to utilize xylose effectively is crucial for economical and sustainable production of fuels. To this end, the xylose-metabolic genes (XYL1, XYL2 and XYL3) from Scheffersomyces stipitis have been introduced into S. cerevisiae. The resulting engineered S. cerevisiae strains, however, often exhibit undesirable phenotypes such as slow xylose assimilation and xylitol accumulation. This work was undertaken to construct an improved xylose-fermenting strain by developing a synthetic isozyme system of xylose reductase (XR). The DXS strain having both wild XR and mutant XR showed low xylitol accumulation and fast xylose consumption compared to the engineered strains expressing only one type of XRs, resulting in improved ethanol yield and productivity. These results suggest that the introduction of the XR-based synthetic isozyme system is a promising strategy to develop efficient xylose-fermenting strains.