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Construction of a Candida utilis strain with ratio-optimized expression of xylose-metabolizing enzyme genes by cocktail multicopy integration method

Paper ID Volume ID Publish Year Pages File Format Full-Text
20873 43195 2013 8 PDF Available
Title
Construction of a Candida utilis strain with ratio-optimized expression of xylose-metabolizing enzyme genes by cocktail multicopy integration method
Abstract

We previously reported the construction of a recombinant Candida utilis strain expressing mXYL1, XYL2 and XYL3, which encode mutated Candida shehatae xylose reductase K275R/N277D, C. shehatae xylitol dehydrogenase and Pichia stipitis xylulokinase to produce ethanol from xylose. However, its productivity was low. In this study, to breed a strain with higher productivity of ethanol from xylose, we used a cocktail multicopy integration method to attain optimized gene dosage of the three enzymes. Gene expression cassettes of the xylose-metabolizing enzymes were simultaneously integrated into C. utilis chromosomes in one step. Measurement of integrated gene copy number and xylose fermentability in all of the resulting integrant strains revealed that the copy number ratio of XYL2/mXYL1 in strains with higher ethanol yield was higher than that in strains with lower ethanol yield, whereas the copy number ratio of mXYL1/XYL3 was lower in strains with higher ethanol yield. The resultant strain CIS35, which was found to be the best producer of ethanol from xylose produced 29.2 g/L of ethanol, yielding 0.402 g ethanol/g xylose. This result provides that C. utilis may be a good candidate as a host for ethanol production from xylose.

Keywords
Candida utilis; Xylose; Ethanol fermentation; Cocktail multicopy integration; Xylose reductase; Xylitol dehydrogenase; Xylulokinase
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Construction of a Candida utilis strain with ratio-optimized expression of xylose-metabolizing enzyme genes by cocktail multicopy integration method
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 115, Issue 5, May 2013, Pages 532–539
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