EC Number   |
Application |
Reference |
|---|
   1.1.1.307 | synthesis |
D-xylose is the second most abundant renewable sugar in nature, and its fermentation to ethanol has great economical potential. Unfortunately, Saccharomyces cerevisiae, which has been optimized for ethanol production, cannot utilize xylose efficiently, while D-xylulose, an isomerization product of D-xylose, can be assimilated. A major strategy for constructing xylose-fermenting Saccharomyces cerevisiae is to introduce genes involved in xylose metabolism from other organisms. Xylose reductase and xylitol dehydrogenase (EC 1.1.1.9) from the xylose-fermenting yeast Pichia stipitis are cloned into Saccharomyces cerevisiae to allow xylose fermentation to ethanol. In this case, xylose is converted into xylulose by the sequential actions of two oxidoreductases. First, Pichia stipitis xylose reductase catalyses the reduction of xylose into xylitol with NAD(P)H as co-substrate. Xylitol is then oxidized by PsXDH (Pichia stipitis xylitol dehydrogenase) which uses NAD+ exclusively as co-substrate to yield xylulose. The different coenzyme specificity of the two enzymes xylose reductase and xylitol dehydrogenase, however, creates an intracellular redox imbalance, which results in low ethanol yields and considerable xylitol by-product formation. A mutant is constructed that shows an altered active site that is more unfavorable for NADPH than NADH in terms of both Km and kcat. There are potentials for application of the mutant (K270S/N272P/S271G/R276F) in constructing a more balanced xylose reductase/xylitol dehydrogenase pathway in recombinant xylose-fermenting Saccharomyces cerevisiae strains |
700009 |
| 1.1.1.307 | synthesis |
Escherichia coli expressing XylA synthesizes 13.3 g/l of xylitol during 20 h of cultivation, when D-xylose (50 g/l) and D-glucose (5 g/l) are added to IPTG-induced cells |
765123 |
| 1.1.1.307 | synthesis |
expression in Candida glycerinogenes WL2002-5, the recombinant strain produces xylitol from D-xylose using glycerol as a cosubstrate for cell growth and NAD (P) H regeneration. 100 g/L D-xylose is completely converted into xylitol when at least 20 g/l glycerol is used as a co-substrate. The strain accumulates 2.1fold increased xylitol concentration over those cells grown on glucose as co-substrate, with a volumetric productivity of 0.83 g/l/h, and a xylitol yield of 98% xylose |
739882 |
| 1.1.1.307 | synthesis |
production of bio-xylitol from D-xylose by an engineered Pichia pastoris expressing a recombinant xylose reductase |
-, 761838 |
| 1.1.1.307 | synthesis |
production of xylitol |
-, 696522 |
| 1.1.1.307 | synthesis |
the cofactor preference of Pichia stipitis xylose reductase is altered by site-directed mutagenesis. When the K270R xylose reductase is combined with a metabolic engineering strategy that ensures high xylose utilization capabilities, a recombinant Saccharomyces cerevisiae strain is created that provides a unique combination of high xylose consumption rate, high ethanol yield and low xylitol yield during ethanolic xylose fermentation |
696885 |
| 1.1.1.307 | synthesis |
the enzyme can be used for industrial production of xylitol from waste xylose mother liquor. Production of xylitol from xylose mother liquor by immobilized Escherichia coli cells containing xylose reductase and glucose dehydrogenase, overview. The immobilization of Escherichia coli strain BL21(DE3)/ pCDFDuet-1-XR-GDH cells results in an increase of storage stability which can expand its potential applications in industries |
760722 |
| 1.1.1.307 | synthesis |
the microalga Chlorella sorokiniana and provide a target for genetic engineering to improve D-xylose utilization for microalgal lipid production |
-, 740206 |
| 1.1.1.307 | synthesis |
this enzyme is one of the most active xylose reductases and may be used for the in vitro production of xylitol |
695733 |
