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Heterologous expression of d-xylulokinase from Pichia stipitis enables high levels of xylitol production by engineered Escherichia coli growing on xylose

Paper ID Volume ID Publish Year Pages File Format Full-Text
31848 44843 2009 8 PDF Available
Title
Heterologous expression of d-xylulokinase from Pichia stipitis enables high levels of xylitol production by engineered Escherichia coli growing on xylose
Abstract

Deletion of the Escherichia coli xylulokinase gene (xylB) is essential for achieving high xylitol titers from xylitol-producing E. coli strains growing on glucose in the presence of xylose. Our study suggests that this is due to XylB-catalyzed toxic synthesis of xylitol-phosphate. This activity prohibits the use of xylose as the sole carbon source during xylitol production by E. coli. To overcome this limitation we turned to the yeast Pichia stipitis, which naturally produces xylitol, as a source of xylulokinase (Xyl3). We examined the effects of plasmid-based expression of Xyl3 versus XylB on growth and xylitol production by engineered E. coli strains. Xylulokinase activity assays show similar levels of functional expression of both enzymes (determined as activity on xylulose), and reveal significantly more activity on xylitol by XylB compared to Xyl3. 31P NMR confirms the production of xylitol-phosphate from in vitro reactions with XylB. Lastly, the replacement of xylB with XYL3 results in drastically enhanced xylitol titers from E. coli strains co-expressing xylose reductase during growth on xylose.

Keywords
Xylitol; Xylitol-phosphate; Xylulokinase; Pichia stipitis; Escherichia coli
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Heterologous expression of d-xylulokinase from Pichia stipitis enables high levels of xylitol production by engineered Escherichia coli growing on xylose
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 11, Issue 1, January 2009, Pages 48–55
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