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Metab Eng. 2014 Jul;24:150-9. doi: 10.1016/j.ymben.2014.05.001. Epub 2014 May 21.

Two-stage transcriptional reprogramming in Saccharomyces cerevisiae for optimizing ethanol production from xylose.

Author information

1
College of Life Sciences, Capital Normal University, Beijing 100048, China; Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada. Electronic address: caolimin@cnu.edu.cn.
2
College of Life Sciences, Capital Normal University, Beijing 100048, China.
3
Department of Biochemical Engineering, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China.
4
Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minneapolis, MN, USA.
5
College of Life Sciences, Capital Normal University, Beijing 100048, China; Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada. Electronic address: weixiao@cnu.edu.cn.

Abstract

Conversion of lignocellulosic material to ethanol is a major challenge in second generation bio-fuel production by yeast Saccharomyces cerevisiae. This report describes a novel strategy named "two-stage transcriptional reprogramming (TSTR)" in which key gene expression at both glucose and xylose fermentation phases is optimized in engineered S. cerevisiae. Through a combined genome-wide screening of stage-specific promoters and the balancing of the metabolic flux, ethanol yields and productivity from mixed sugars were significantly improved. In a medium containing 50g/L glucose and 50g/L xylose, the top-performing strain WXY12 rapidly consumed glucose within 12h and within 84h it consistently achieved an ethanol yield of 0.48g/g total sugar, which was 94% of the theoretical yield. WXY12 utilizes a KGD1 inducible promoter to drive xylose metabolism, resulting in much higher ethanol yield than a reference strain using a strong constitutive PGK1 promoter. These promising results validate the TSTR strategy by synthetically regulating the xylose assimilation pathway towards efficient xylose fermentation.

KEYWORDS:

Ethanol; Saccharomyces cerevisiae; Two-stage transcription reprogramming; Xylose; Xylose reductase

PMID:
24858789
DOI:
10.1016/j.ymben.2014.05.001
[Indexed for MEDLINE]

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