Abstract
The product spectrum of a soil bacterium Corynebacterium glutamicum was extended to include a functional sugar xylitol. The recombinant C. glutamicum, engineered to express the xylose reductase gene XYL1of Pichia stipitis, produced xylose reductase with a specific activity of ca. 0.6. U/mg protein. Due to the absence of xylose isomerase and xylitol dehydrogenase genes, loose catabolite repression, high NADPH regeneration capacity, and tolerance against sugar-induced osmotic stress, the recombinant biocatalyst was able to efficiently produce xylitol from d-xylose using glucose as source of reducing equivalents. A fed-batch culture-based biotransformation allowed xylitol to accumulate to a concentration of 34.4. g/L (226. mM) in the medium with the specific productivity and product yield of xylose of 0.092. g/g dry cells/h and over 97%, respectively. The molar yield of xylitol to energy source during the biotransformation reached approximately 1.6. mol of xylose/mol of glucose.
Original language | English |
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Pages (from-to) | 366-371 |
Number of pages | 6 |
Journal | Enzyme and Microbial Technology |
Volume | 46 |
Issue number | 5 |
DOIs | |
State | Published - Apr 2010 |
Bibliographical note
Funding Information:This work was supported by the Seoul Development Institute (No. KU080657).
Keywords
- Biotransformation
- Corynebacterium glutamicum
- Fed-batch cultivation
- Xylitol