کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
31848 44843 2009 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Heterologous expression of d-xylulokinase from Pichia stipitis enables high levels of xylitol production by engineered Escherichia coli growing on xylose
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
Heterologous expression of d-xylulokinase from Pichia stipitis enables high levels of xylitol production by engineered Escherichia coli growing on xylose
چکیده انگلیسی

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.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Metabolic Engineering - Volume 11, Issue 1, January 2009, Pages 48–55
نویسندگان
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