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Xylose isomerase overexpression along with engineering of the pentose phosphate pathway and evolutionary engineering enable rapid xylose utilization and ethanol production by Saccharomyces cerevisiae

Paper ID Volume ID Publish Year Pages File Format Full-Text
31712 44832 2012 12 PDF Available
Title
Xylose isomerase overexpression along with engineering of the pentose phosphate pathway and evolutionary engineering enable rapid xylose utilization and ethanol production by Saccharomyces cerevisiae
Abstract

Xylose is the main pentose and second most abundant sugar in lignocellulosic feedstocks. To improve xylose utilization, necessary for the cost-effective bioconversion of lignocellulose, several metabolic engineering approaches have been employed in the yeast Saccharomyces cerevisiae. In this study, we describe the rational metabolic engineering of a S. cerevisiae strain, including overexpression of the Piromyces xylose isomerase gene (XYLA), Pichia stipitis xylulose kinase (XYL3) and genes of the non-oxidative pentose phosphate pathway (PPP). This engineered strain (H131-A3) was used to initialize a three-stage process of evolutionary engineering, through first aerobic and anaerobic sequential batch cultivation followed by growth in a xylose-limited chemostat. The evolved strain H131-A3-ALCS displayed significantly increased anaerobic growth rate (0.203±0.006 h−1) and xylose consumption rate (1.866 g g−1 h−1) along with high ethanol conversion yield (0.41 g/g). These figures exceed by a significant margin any other performance metrics on xylose utilization and ethanol production by S. cerevisiae reported to-date. Further inverse metabolic engineering based on functional complementation suggested that efficient xylose assimilation is attributed, in part, to the elevated expression level of xylose isomerase, which was accomplished through the multiple-copy integration of XYLA in the chromosome of the evolved strain.

► Rational and evolutionary metabolic engineering were carried out in S. cerevisiae. ► Xylose fermentation performance of the evolved strain is the best reported to-date. ► High expression level of xylose isomerase is necessary for rapid xylose assimilation.

Keywords
Xylose isomerase; Saccharomyces cerevisiae; Evolutionary engineering; Inverse metabolic engineering; Xylose utilization; Ethanol production
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Xylose isomerase overexpression along with engineering of the pentose phosphate pathway and evolutionary engineering enable rapid xylose utilization and ethanol production by Saccharomyces cerevisiae
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 14, Issue 6, November 2012, Pages 611–622
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us