1.1.1.9: D-xylulose reductase
This is an abbreviated version!
For detailed information about D-xylulose reductase, go to the full flat file.
Word Map on EC 1.1.1.9
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1.1.1.9
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xanthine
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xylose
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stipitis
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pichia
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xylulokinase
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uric
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lignocellulosic
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pentose
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candida
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molybdenum
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xylose-fermenting
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allopurinol
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hypoxanthine
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xanthinuria
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xylose-utilizing
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hydrolysate
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l-arabitol
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guilliermondii
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bagasse
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bioethanol
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l-arabinose
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hemicellulosic
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marxianus
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scheffersomyces
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rosy
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d-sorbitol
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oxygen-limited
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l-xylulose
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mocos
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tannophilus
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oxydans
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ribitol
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molecular biology
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gluconobacter
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pachysolen
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pseudoobscura
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sulfurase
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shehatae
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synthesis
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biotechnology
- 1.1.1.9
- xanthine
- xylose
- stipitis
- pichia
- xylulokinase
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uric
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lignocellulosic
- pentose
- candida
- molybdenum
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xylose-fermenting
- allopurinol
- hypoxanthine
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xanthinuria
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xylose-utilizing
- hydrolysate
- l-arabitol
- guilliermondii
- bagasse
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bioethanol
- l-arabinose
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hemicellulosic
- marxianus
- scheffersomyces
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rosy
- d-sorbitol
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oxygen-limited
- l-xylulose
- mocos
- tannophilus
- oxydans
- ribitol
- molecular biology
- gluconobacter
- pachysolen
- pseudoobscura
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sulfurase
- shehatae
- synthesis
- biotechnology
Reaction
Synonyms
2,3-cis-polyol(DPN) dehydrogenase (C3-5), D-xylulose reductase A, erythritol dehydrogenase, GmXDH, IoXyl2p, McXDH, More, NAD+-dependent XDH, NAD+-dependent xylitol dehydrogenase, NAD+-linked xylitol dehydrogenase, NAD-dependent xylitol dehydrogenase, NADH-dependent XDH, NADH-dependent xylitol dehydrogenase, nicotinamide adenine dinucleotide-dependent xylitol dehydrogenase 2, pentitol-DPN dehydrogenase, Ps-XDH, PsXDH, reductase, D-xylulose, RpXDH, slSDH, SpXYL2.2, SsXyl2p, TdXyl2p, XDH, XDH-Y25, xdhA, XL2, XYL2, XYL2.1, XYL2.2, xylitol dehydrogenase, xylitol dehydrogenase 2, xylitol-2-dehydrogenase
ECTree
1.1.1.9 D-xylulose reductaseAdvanced search results
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results (Engineering
Engineering on EC 1.1.1.9 - D-xylulose reductase
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PROTEIN VARIANTS 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
D202A/L203R/V204S/E205P/S206R
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site-directed mutagenesis, introduction of multiple site-directed mutations in the coenzyme-binding pocket of Galactocandida mastotermitis XDH to enable activity with NADP+, which is lacking in the wild-type enzyme, genetic metabolic engineering for improvement of xylose metabolism and fermentation in wild-type Saccharomyces cerevisiae strains, which are not able to naturally metabolize D-xylulose, overview
E154C
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mutant bearing a disrupted Zn2+ binding site: purified preparations show a variable Zn2+ (0.10-0.40 atom/subunit), mutant exhibits a constant catalytic Zn2+ centre activity and does not require exogenous Zn2+ for activity or stability. E154C retains 0.019% and 0.74% of wild-type catalytic efficiency (kcat/Km (sorbitol): 7800/Msec and kcat:161/sec) for NAD+-dependent oxidation of sorbitol at 25°C respectively. The pH profile of kcat/Ksorbitol for E154C decreases below an apparent pK of 9.1, reflecting a shift in pK by about +1.7-1.9 pH units compared with the corresponding pH profiles for wild-type. IC50 (ZnSO4): 0.005 mM
synthesis
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use of enzyme in a process for producing xylitol from D-glucose
D38S/M39R
the mutant enzyme is able to exclusively use NADP+, with no loss of activity
D205A
site-directed mutagenesis, coenzyme preference of the mutant RpXDH is partially reversed from NAD+ to NADP+
D205A/I206R
D205A
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site-directed mutagenesis, coenzyme preference of the mutant RpXDH is partially reversed from NAD+ to NADP+
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D205A/I206R
D207A
kcat/Km for NAD+ is 3.6fold lower than wild-type value, kcat/Km for NADP+ is 4.3fold higher than wild-type value
D207A/F209S
kcat/Km for NAD+ is 2.2fold lower than wild-type value, kcat/Km for NADP+ is 745fold higher than wild-type value
D207A/I208R
kcat/Km for NAD+ is 2.5fold lower than wild-type value, kcat/Km for NADP+ is 229fold higher than wild-type value
D207A/I208R/F209S
D207A/I208R/F209S/N211R
kcat/Km for NAD+ is 32.9fold lower than wild-type value, kcat/Km for NADP+ is 4292fold higher than wild-type value, increased thermostability
D207A/I208R/F209T
kcat/Km for NAD+ is 2.4fold lower than wild-type value, kcat/Km for NADP+ is 4754fold higher than wild-type value
D207A/I208R/F209Y
kcat/Km for NAD+ is 6.9fold lowerthan wild-type value, kcat/Km for NADP+ is 788fold higher than wild-type value
F209S
kcat/Km for NAD+ is 1.9fold lower than wild-type value, kcat/Km for NADP+ is 31.4fold higher than wild-type value
I208R
kcat/Km for NAD+ is nearly identical to wild-type value, kcat/Km for NADP+ is 44fold higher than wild-type value
I208R/F209S
kcat/Km for NAD+ is 30.7fold lower than wild-type value, kcat/Km for NADP+ is 1.5fold higher than wild-type value
N211R
kcat/Km for NAD+ is 1.1fold lower than wild-type value, kcat/Km for NADP+ is 7.6fold higher than wild-type value
S96C/S99C/Y102C
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specific activity (U/min): 1440, half denaturation temperature T1/2 (°C): 46.1, thermal transition temperature Tcd (°C): 47.5
S96C/S99C/Y102C/D207A/I208R/F209S
S96C/S99C/Y102C/D207A/I208R/F209S/N211R
kcat/Km for NAD+ is 26.5fold lower than wild-type value, kcat/Km for NADP+ is 16154fold higher than wild-type value
S96C/S99C/Y102C/E101F
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specific activity (U/min): 1550, half denaturation temperature T1/2 (°C): 50.9, thermal transition temperature Tcd (°C): 50.5
S96C/S99C/Y102C/F98R
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specific activity (U/min): 1510, half denaturation temperature T1/2 (°C): 53.1, thermal transition temperature Tcd (°C): 51.7
S96C/S99C/Y102C/F98R/E101F
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specific activity (U/min): 1620, half denaturation temperature T1/2 (°C): 56.0, thermal transition temperature Tcd (°C): 53.8
S96C/S99C/Y102C/H112D
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specific activity (U/min): 1360, half denaturation temperature T1/2 (°C): 44.0, thermal transition temperature Tcd (°C): 47.0
S96C/S99C/Y102C/P95S
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specific activity (U/min): 1220, half denaturation temperature T1/2 (°C): 37.4, thermal transition temperature Tcd (°C): 43.5
S96C/S99CY102C
kcat/Km for NAD+ is 1.1fold lower than wild-type value, kcat/Km for NADP+ is 8.8fold higher than wild-type value
additional information
D205A/I206R
site-directed mutagenesis, coenzyme preference of the mutant RpXDH is reversed from NAD+ to NADP+
D205A/I206R
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site-directed mutagenesis, coenzyme preference of the mutant RpXDH is reversed from NAD+ to NADP+
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D207A/I208R/F209S
kcat/Km for NAD+ is 15.2fold lower than wild-type value, kcat/Km for NADP+ is 4292fold higher than wild-type value, increased thermostability
D207A/I208R/F209S
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mutant bearing a reversal of coenzyme specificity from NAD+ to NADP+ is introduced into Saccharomyces cerevisiae. kcat/Km (NAD+): 181 l/min/mmol, kcat/Km (NADP+): 2790 l/min/mmol, Km (xylitol in the presence of NAD+): 31.1 mM, NADP+-dependent activity: 0.782 U/mg, NAD+-dependent activity: 0.271 U/mg. In xylose fermentation a large decrease in xylitol and glycerol yield is shown, while the xylose consumption and ethanol yield are decreased
S96C/S99C/Y102C/D207A/I208R/F209S
kcat/Km for NAD+ is 36.7fold lower than wild-type value, kcat/Km for NADP+ 16462is fold higher than wild-type value
S96C/S99C/Y102C/D207A/I208R/F209S
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mutant bearing a reversal of coenzyme specificity from NAD+ to NADP+ and additional zinc-binding site for thermostability, is introduced into Saccharomyces cerevisiae. kcat/Km (NADP+): 10700 l/min/mmol, Km (xylitol in the presence of NAD+): 111 mM , NADP+-dependent activity: 0.689 U/mg, NAD+-dependent activity: 0.136 U/mg. The xylose consumption and ethanol yield are decreased, and the xylitol yield is increased, because of low XDH activity
additional information
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generation of xdhA and ladA deletion mutants and double-deletion mutant, that show decreased dehydrogenase activities and increased xylitol production from D-xylose compared to the KBN616 wild-type strain, overview
additional information
generation of xdhA and ladA deletion mutants and double-deletion mutant, that show decreased dehydrogenase activities and increased xylitol production from D-xylose compared to the KBN616 wild-type strain, overview
additional information
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construction of deletion mutants of xdhA and ladA-xdhA, to generate mutants with decreased dehydrogenase activities and increased xylitol production. Genomic DNA from Aspergillus oryzae strain KBN616 is used as the template for amplification of the three xdhA and ladA inserts. Activities of xylitol dehydrogenase and xylose reductase in the mutant strains, phenotype, overview
additional information
construction of deletion mutants of xdhA and ladA-xdhA, to generate mutants with decreased dehydrogenase activities and increased xylitol production. Genomic DNA from Aspergillus oryzae strain KBN616 is used as the template for amplification of the three xdhA and ladA inserts. Activities of xylitol dehydrogenase and xylose reductase in the mutant strains, phenotype, overview
additional information
construction of deletion mutants of xdhA by homologous transformation, to generate mutants with decreased dehydrogenase activities and increased xylitol production. Gene pyrG is used as a selectable marker. Consumption of D-xylose for xdhA2-1 and ladA2-1 is similar to that of KBN616. Mutant xdhA2-1 displays the highest xylitol productivity. XdhA-disrupted mutant xdhA2-1 exhibits the highest xylitol productivity from D-xylose and is selected for further production of xylitol from oat spelt xylan
additional information
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construction of deletion mutants of xdhA by homologous transformation, to generate mutants with decreased dehydrogenase activities and increased xylitol production. Gene pyrG is used as a selectable marker. Consumption of D-xylose for xdhA2-1 and ladA2-1 is similar to that of KBN616. Mutant xdhA2-1 displays the highest xylitol productivity. XdhA-disrupted mutant xdhA2-1 exhibits the highest xylitol productivity from D-xylose and is selected for further production of xylitol from oat spelt xylan
additional information
construction of xdhA gene disruption mutant xdhA2-1 by homologous transformation into Aspergillus oryzae strain P5 (DELTApyrG), and pyrG is used as a selectable marker, phenotype, overview
additional information
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construction of xdhA gene disruption mutant xdhA2-1 by homologous transformation into Aspergillus oryzae strain P5 (DELTApyrG), and pyrG is used as a selectable marker, phenotype, overview
additional information
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generation of xdhA and ladA deletion mutants and double-deletion mutant, that show decreased dehydrogenase activities and increased xylitol production from D-xylose compared to the KBN616 wild-type strain, overview
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additional information
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construction of deletion mutants of xdhA and ladA-xdhA, to generate mutants with decreased dehydrogenase activities and increased xylitol production. Genomic DNA from Aspergillus oryzae strain KBN616 is used as the template for amplification of the three xdhA and ladA inserts. Activities of xylitol dehydrogenase and xylose reductase in the mutant strains, phenotype, overview
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additional information
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construction of xdhA gene disruption mutant xdhA2-1 by homologous transformation into Aspergillus oryzae strain P5 (DELTApyrG), and pyrG is used as a selectable marker, phenotype, overview
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additional information
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construction of deletion mutants of xdhA by homologous transformation, to generate mutants with decreased dehydrogenase activities and increased xylitol production. Gene pyrG is used as a selectable marker. Consumption of D-xylose for xdhA2-1 and ladA2-1 is similar to that of KBN616. Mutant xdhA2-1 displays the highest xylitol productivity. XdhA-disrupted mutant xdhA2-1 exhibits the highest xylitol productivity from D-xylose and is selected for further production of xylitol from oat spelt xylan
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additional information
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strain overexpressing enzyme has improved xylitol productivity, production of up to 57g/l xylitol from 225 g/l D-arabitol, via D-xylulose
additional information
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to improve characteristics of xylose fermentation, the recombinant strain Delta xyl1 Delta xyl2-ADelta xyl2-B, with deletions of genes encoding first enzymes of xylose utilization (NAD(P)H-dependent xylose reductase and NAD-dependent xylitol dehydrogenases, respectively), is constructed and used as a recipient for co-overexpression of the Escherichia coli xylA gene coding for xylose isomerase and endogenous XYL3 gene coding for xylulokinase. Recombinant strains display improved ethanol production during the fermentation of xylose
additional information
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recombinant Saccharomyces cerevisiae strain TMB3057 with high activity of both xylose reductase and xylitol dehydrogenase show increased ethanol formation from xylose at the expense of xylitol formation
additional information
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coenzyme specificities of the NADPH-preferring xylose reductase, EC 1.1.1.307, and the NAD+-dependent xylitol dehydrogenase are targeted in previous studies by protein design or evolution with the aim of improving the recycling of NADH or NADPH in their two-step pathway, converting xylose to xylulose. Yeast strains expressing variant pairs of both enzymes that according to in vitro kinetic data are suggested to be much better matched in coenzyme usage than the corresponding pair of wild-type enzymes, exhibit widely varying capabilities for xylose fermentation, bi-substrate kinetic analysis, and statistical analysis, overview. Engineered strains of Saccharomyces cerevisiae have engineered forms of xylose reductase or xylose dehydrogenase and imporved performance in xylose fermentation
additional information
Saccharomyces cerevisiae, the preferred microorganism for large-scale ethanol production, does not naturally consume xylose. Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways are introduced into two robust industrial Saccharomyces cerevisiae strains, PE-2DELTAGRE3 and CA11, evaluated in synthetic media and corn cob hemicellulosic hydrolysate (non-detoxified corn cob hydrolysate) and the results are correlated with the differential enzyme activities found in the xylose-pathway engineered strains, evaluation of xylose fermentation capacity in oxygen-deprived conditions at 30°C and 40°C. Regarding the CA11-derived strains, the XR activity is higher in the strain with both pathways than in the one solely expressing XR/XDH, while the XDH activity at 30°C is higher in the CA11-XR/XDH strain. The sole expression of XI increases the fermentative capacity of both strains in synthetic media at 30°C and 40°C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results are observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect results from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%. Advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose, and the simultaneous utilization of XR/XDH and XI pathways compared to the single expression of XR/XDH or XI improves ethanol production from non-detoxified hemicellulosic hydrolysates
additional information
-
Saccharomyces cerevisiae, the preferred microorganism for large-scale ethanol production, does not naturally consume xylose. Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways are introduced into two robust industrial Saccharomyces cerevisiae strains, PE-2DELTAGRE3 and CA11, evaluated in synthetic media and corn cob hemicellulosic hydrolysate (non-detoxified corn cob hydrolysate) and the results are correlated with the differential enzyme activities found in the xylose-pathway engineered strains, evaluation of xylose fermentation capacity in oxygen-deprived conditions at 30°C and 40°C. Regarding the CA11-derived strains, the XR activity is higher in the strain with both pathways than in the one solely expressing XR/XDH, while the XDH activity at 30°C is higher in the CA11-XR/XDH strain. The sole expression of XI increases the fermentative capacity of both strains in synthetic media at 30°C and 40°C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results are observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect results from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%. Advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose, and the simultaneous utilization of XR/XDH and XI pathways compared to the single expression of XR/XDH or XI improves ethanol production from non-detoxified hemicellulosic hydrolysates
additional information
-
Saccharomyces cerevisiae, the preferred microorganism for large-scale ethanol production, does not naturally consume xylose. Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways are introduced into two robust industrial Saccharomyces cerevisiae strains, PE-2DELTAGRE3 and CA11, evaluated in synthetic media and corn cob hemicellulosic hydrolysate (non-detoxified corn cob hydrolysate) and the results are correlated with the differential enzyme activities found in the xylose-pathway engineered strains, evaluation of xylose fermentation capacity in oxygen-deprived conditions at 30°C and 40°C. Regarding the CA11-derived strains, the XR activity is higher in the strain with both pathways than in the one solely expressing XR/XDH, while the XDH activity at 30°C is higher in the CA11-XR/XDH strain. The sole expression of XI increases the fermentative capacity of both strains in synthetic media at 30°C and 40°C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results are observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect results from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%. Advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose, and the simultaneous utilization of XR/XDH and XI pathways compared to the single expression of XR/XDH or XI improves ethanol production from non-detoxified hemicellulosic hydrolysates
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additional information
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expression of the xylitol dehydrogenase-encoding gene XYL2 of Pichia stipitis in the transketolase-deficient Saccharomyces cerevisiae strain results in an 8.5fold enhancement of the total amount of the excreted sugar alcohols ribitol and xylitol. The additional introduction of the 2-deoxy-glucose 6-phosphate phosphatase-encoding gene DOG1 into the transketolase-deficient strain expressing the XYL2 gene resulted in a further 1.6fold increase in ribitol production
additional information
engineered Saccharomyces cerevisiae strain DGX23 overexpressing aldose reductase GRE3, xylitol dehydrogenase XYL2, and xylulokinase XYL3 can ferment xylose as well as a mixture of glucose and xylose with higher ethanol yields and productivities than those of an isogenic strain overexpressing xylose reductase XYL1, xylitol dehydrogenase XYL2, and xylulokinase XYL3 under oxygen-limited conditions. Optimized expression levels of GRE3, XYL2, and XYL3 can overcome redox imbalance during xylose fermentation by engineered Saccharomyces cerevisiae under oxygen-limited conditions, anaerobic xylose fermentation
additional information
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engineered Saccharomyces cerevisiae strain DGX23 overexpressing aldose reductase GRE3, xylitol dehydrogenase XYL2, and xylulokinase XYL3 can ferment xylose as well as a mixture of glucose and xylose with higher ethanol yields and productivities than those of an isogenic strain overexpressing xylose reductase XYL1, xylitol dehydrogenase XYL2, and xylulokinase XYL3 under oxygen-limited conditions. Optimized expression levels of GRE3, XYL2, and XYL3 can overcome redox imbalance during xylose fermentation by engineered Saccharomyces cerevisiae under oxygen-limited conditions, anaerobic xylose fermentation
additional information
enzyme XDH is changed from NAD+-dependent to NADP+-dependent, xylitol accumulation is reduced and ethanol production improved using protein engineering for reversing the dependency of XDH from NAD+ to NADP+. Construction of a set of recombinant Saccharomyces cerevisiae carrying a mutated strictly NADPH-dependent XR and NADP+-dependent XDH genes with overexpression of endogenous xylulokinase (XK), effects of complete NADPH/NADP+ recycling on ethanol fermentation and xylitol accumulation, overview. The mutated strains demonstrate 0% and 10% improvement in ethanol production, and reduced xylitol accumulation, ranging 34.4-54.7% compared with the control strain
additional information
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enzyme XDH is changed from NAD+-dependent to NADP+-dependent, xylitol accumulation is reduced and ethanol production improved using protein engineering for reversing the dependency of XDH from NAD+ to NADP+. Construction of a set of recombinant Saccharomyces cerevisiae carrying a mutated strictly NADPH-dependent XR and NADP+-dependent XDH genes with overexpression of endogenous xylulokinase (XK), effects of complete NADPH/NADP+ recycling on ethanol fermentation and xylitol accumulation, overview. The mutated strains demonstrate 0% and 10% improvement in ethanol production, and reduced xylitol accumulation, ranging 34.4-54.7% compared with the control strain
additional information
engineered Sacchyromyces cerevisiae expressing NADPH-linked xylose reductase (XR) and NAD+-linked xylitol dehydrogenase (XDH) produces substantial amounts of the reduced byproducts under anaerobic conditions due to the cofactor difference of XR and XDH. While the additional expression of a water-forming NADH oxidase (NoxE) from Lactococcus lactis in engineered Saccharomyces cerevisiae with the XR/XDH pathway leads to reduced glycerol and xylitol production and increased ethanol yields from xylose, volumetric ethanol productivities by the engineered yeast decrease because of growth defects from the overexpression of noxE. High cell density inoculum for xylose fermentation by strain SR8 expressing noxE, resulting in strain SR8N, shows a higher ethanol yield and lower byproduct yields, and also exhibits a high ethanol productivity during xylose fermentation. Growth defects from noxE overexpression can be overcome in the case of fermenting lignocellulose-derived sugars such as glucose and xylosen
additional information
construction of efficient xylose-fermenting Saccharomyces cerevisiae strain DXS through a synthetic isozyme system of xylose reductase from Scheffersomyces stipitis. The xylose-metabolic genes XYL1 (EC 1.1.1.307), XYL2, and XYL3 (EC 2.7.1.17) from Scheffersomyces stipitis are introduced into Saccharomyces cerevisiae. Construction of control strains SR6 and MM through random integration of the XR (NADPH) or mXR (NADH) expression cassette, respectively, at the multipled elements of the genome of Saccharomyces cerevisiae strain D452-2. Fermentation parameters of engineered Saccharomyces cerevisiae strains in mixed sugar fermentations (glucose and xylose), overview
additional information
efficient uptake and reduction of xylose photoautotrophically in Synechococcus elongatus strain PCC7942 are demonstrated upon introduction of an effective xylose transporter from Escherichia coli (Ec-XylE) and the NADPH-dependent xylose reductase from Candida boidinii (Cb-XR). Simultaneous activation of xylose uptake and matching of cofactor specificity enables an average xylitol yield of 0.9 g/g xylose and a maximum productivity of about 0.15 g/l/day/OD with increased level of xylose supply. High-density conversion of xylose to xylitol using concentrated resting cells further pushes the titer of xylitol formation to 33 g/l in six days with 85% of maximum theoretical yield. Comparison of the efficiencies of the two routes for xylitol biosynthesis, detailed overview
additional information
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construction of efficient xylose-fermenting Saccharomyces cerevisiae strain DXS through a synthetic isozyme system of xylose reductase from Scheffersomyces stipitis. The xylose-metabolic genes XYL1 (EC 1.1.1.307), XYL2, and XYL3 (EC 2.7.1.17) from Scheffersomyces stipitis are introduced into Saccharomyces cerevisiae. Construction of control strains SR6 and MM through random integration of the XR (NADPH) or mXR (NADH) expression cassette, respectively, at the multipled elements of the genome of Saccharomyces cerevisiae strain D452-2. Fermentation parameters of engineered Saccharomyces cerevisiae strains in mixed sugar fermentations (glucose and xylose), overview
-
additional information
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engineered Sacchyromyces cerevisiae expressing NADPH-linked xylose reductase (XR) and NAD+-linked xylitol dehydrogenase (XDH) produces substantial amounts of the reduced byproducts under anaerobic conditions due to the cofactor difference of XR and XDH. While the additional expression of a water-forming NADH oxidase (NoxE) from Lactococcus lactis in engineered Saccharomyces cerevisiae with the XR/XDH pathway leads to reduced glycerol and xylitol production and increased ethanol yields from xylose, volumetric ethanol productivities by the engineered yeast decrease because of growth defects from the overexpression of noxE. High cell density inoculum for xylose fermentation by strain SR8 expressing noxE, resulting in strain SR8N, shows a higher ethanol yield and lower byproduct yields, and also exhibits a high ethanol productivity during xylose fermentation. Growth defects from noxE overexpression can be overcome in the case of fermenting lignocellulose-derived sugars such as glucose and xylosen
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additional information
-
efficient uptake and reduction of xylose photoautotrophically in Synechococcus elongatus strain PCC7942 are demonstrated upon introduction of an effective xylose transporter from Escherichia coli (Ec-XylE) and the NADPH-dependent xylose reductase from Candida boidinii (Cb-XR). Simultaneous activation of xylose uptake and matching of cofactor specificity enables an average xylitol yield of 0.9 g/g xylose and a maximum productivity of about 0.15 g/l/day/OD with increased level of xylose supply. High-density conversion of xylose to xylitol using concentrated resting cells further pushes the titer of xylitol formation to 33 g/l in six days with 85% of maximum theoretical yield. Comparison of the efficiencies of the two routes for xylitol biosynthesis, detailed overview
-
additional information
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construction of efficient xylose-fermenting Saccharomyces cerevisiae strain DXS through a synthetic isozyme system of xylose reductase from Scheffersomyces stipitis. The xylose-metabolic genes XYL1 (EC 1.1.1.307), XYL2, and XYL3 (EC 2.7.1.17) from Scheffersomyces stipitis are introduced into Saccharomyces cerevisiae. Construction of control strains SR6 and MM through random integration of the XR (NADPH) or mXR (NADH) expression cassette, respectively, at the multipled elements of the genome of Saccharomyces cerevisiae strain D452-2. Fermentation parameters of engineered Saccharomyces cerevisiae strains in mixed sugar fermentations (glucose and xylose), overview
-
additional information
-
efficient uptake and reduction of xylose photoautotrophically in Synechococcus elongatus strain PCC7942 are demonstrated upon introduction of an effective xylose transporter from Escherichia coli (Ec-XylE) and the NADPH-dependent xylose reductase from Candida boidinii (Cb-XR). Simultaneous activation of xylose uptake and matching of cofactor specificity enables an average xylitol yield of 0.9 g/g xylose and a maximum productivity of about 0.15 g/l/day/OD with increased level of xylose supply. High-density conversion of xylose to xylitol using concentrated resting cells further pushes the titer of xylitol formation to 33 g/l in six days with 85% of maximum theoretical yield. Comparison of the efficiencies of the two routes for xylitol biosynthesis, detailed overview
-
additional information
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construction of efficient xylose-fermenting Saccharomyces cerevisiae strain DXS through a synthetic isozyme system of xylose reductase from Scheffersomyces stipitis. The xylose-metabolic genes XYL1 (EC 1.1.1.307), XYL2, and XYL3 (EC 2.7.1.17) from Scheffersomyces stipitis are introduced into Saccharomyces cerevisiae. Construction of control strains SR6 and MM through random integration of the XR (NADPH) or mXR (NADH) expression cassette, respectively, at the multipled elements of the genome of Saccharomyces cerevisiae strain D452-2. Fermentation parameters of engineered Saccharomyces cerevisiae strains in mixed sugar fermentations (glucose and xylose), overview
-
additional information
-
efficient uptake and reduction of xylose photoautotrophically in Synechococcus elongatus strain PCC7942 are demonstrated upon introduction of an effective xylose transporter from Escherichia coli (Ec-XylE) and the NADPH-dependent xylose reductase from Candida boidinii (Cb-XR). Simultaneous activation of xylose uptake and matching of cofactor specificity enables an average xylitol yield of 0.9 g/g xylose and a maximum productivity of about 0.15 g/l/day/OD with increased level of xylose supply. High-density conversion of xylose to xylitol using concentrated resting cells further pushes the titer of xylitol formation to 33 g/l in six days with 85% of maximum theoretical yield. Comparison of the efficiencies of the two routes for xylitol biosynthesis, detailed overview
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additional information
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combination of xylose reductase from Spathaspora arborariae with xylitol dehydrogenase from Spathaspora passalidarum to promote xylose consumption and fermentation into xylitol in Saccharomyces cerevisiae. Recombinant co-expression of Spathaspora arborariae xylose reductase gene (SaXYL1) that accepts both NADH and NADPH as co-substrates, and of Spathaspora passalidarum strain UFMG-HM.19.1AT NADPH-dependent xylose reductase (SpXYL1.1 gene) or the SpXYL2.2 gene from Spathaspora passalidarum strain UFMG-CM-Y474 in a Saccharomyces cerevisiae strain overexpressing the native XKS1 gene encoding xylulokinase, as well as being deleted in the alkaline phosphatase encoded by the PHO13 gene. Strains expressing the Spathaspora enzymes consumes xylose with xylitol as the major fermentation product. Higher specific growth rates, xylose consumption, and xylitol volumetric productivities are obtained by the co-expression of the SaXYL1 and SpXYL2.2 genes, when compared with the co-expression of the NADPH-dependent SpXYL1.1 xylose reductase. During glucose-xylose co-fermentation by the strain with co-expression of the SaXYL1 and SpXYL2.2 genes, both ethanol and xylitol are produced efficiently. Method development and evaluation, detailed overview
additional information
the combinatorial expression of two xylose reductase (XR) genes and two xylitol dehydrogenase (XDH) genes from Spathaspora passalidarum and the heterologous expression of the Piromyces sp. xylose isomerase (XI) gene are induced in Aureobasidium pullulans strain CBS 110374. Overexpression of XYL1.2 (encoding XR) and XYL2.2 (encoding XDH) is the most beneficial for xylose utilization, resulting in a 17.76% increase in consumed xylose compared with the parent strain, whereas the introduction of the Piromyces sp. XI pathway fails to enhance xylose utilization efficiency. Construction of knock-in mutants, method, evaluation of internal redox state, xylose utilization and cell growth of the recombinant strains, pH 5.8, 28°C, comparison the fermentation abilities of the parent strain and the recombinant strains using several carbon sources, overview
additional information
the combinatorial expression of two xylose reductase (XR) genes and two xylitol dehydrogenase (XDH) genes from Spathaspora passalidarum and the heterologous expression of the Piromyces sp. xylose isomerase (XI) gene are induced in Aureobasidium pullulans strain CBS 110374. Overexpression of XYL1.2 (encoding XR) and XYL2.2 (encoding XDH) is the most beneficial for xylose utilization, resulting in a 17.76% increase in consumed xylose compared with the parent strain, whereas the introduction of the Piromyces sp. XI pathway fails to enhance xylose utilization efficiency. Construction of knock-in mutants, method, evaluation of internal redox state, xylose utilization and cell growth of the recombinant strains, pH 5.8, 28°C, comparison the fermentation abilities of the parent strain and the recombinant strains using several carbon sources, overview
additional information
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the combinatorial expression of two xylose reductase (XR) genes and two xylitol dehydrogenase (XDH) genes from Spathaspora passalidarum and the heterologous expression of the Piromyces sp. xylose isomerase (XI) gene are induced in Aureobasidium pullulans strain CBS 110374. Overexpression of XYL1.2 (encoding XR) and XYL2.2 (encoding XDH) is the most beneficial for xylose utilization, resulting in a 17.76% increase in consumed xylose compared with the parent strain, whereas the introduction of the Piromyces sp. XI pathway fails to enhance xylose utilization efficiency. Construction of knock-in mutants, method, evaluation of internal redox state, xylose utilization and cell growth of the recombinant strains, pH 5.8, 28°C, comparison the fermentation abilities of the parent strain and the recombinant strains using several carbon sources, overview
additional information
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the combinatorial expression of two xylose reductase (XR) genes and two xylitol dehydrogenase (XDH) genes from Spathaspora passalidarum and the heterologous expression of the Piromyces sp. xylose isomerase (XI) gene are induced in Aureobasidium pullulans strain CBS 110374. Overexpression of XYL1.2 (encoding XR) and XYL2.2 (encoding XDH) is the most beneficial for xylose utilization, resulting in a 17.76% increase in consumed xylose compared with the parent strain, whereas the introduction of the Piromyces sp. XI pathway fails to enhance xylose utilization efficiency. Construction of knock-in mutants, method, evaluation of internal redox state, xylose utilization and cell growth of the recombinant strains, pH 5.8, 28°C, comparison the fermentation abilities of the parent strain and the recombinant strains using several carbon sources, overview
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additional information
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the combinatorial expression of two xylose reductase (XR) genes and two xylitol dehydrogenase (XDH) genes from Spathaspora passalidarum and the heterologous expression of the Piromyces sp. xylose isomerase (XI) gene are induced in Aureobasidium pullulans strain CBS 110374. Overexpression of XYL1.2 (encoding XR) and XYL2.2 (encoding XDH) is the most beneficial for xylose utilization, resulting in a 17.76% increase in consumed xylose compared with the parent strain, whereas the introduction of the Piromyces sp. XI pathway fails to enhance xylose utilization efficiency. Construction of knock-in mutants, method, evaluation of internal redox state, xylose utilization and cell growth of the recombinant strains, pH 5.8, 28°C, comparison the fermentation abilities of the parent strain and the recombinant strains using several carbon sources, overview
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additional information
Spathaspora passalidarum UFMG-CM-Y474
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combination of xylose reductase from Spathaspora arborariae with xylitol dehydrogenase from Spathaspora passalidarum to promote xylose consumption and fermentation into xylitol in Saccharomyces cerevisiae. Recombinant co-expression of Spathaspora arborariae xylose reductase gene (SaXYL1) that accepts both NADH and NADPH as co-substrates, and of Spathaspora passalidarum strain UFMG-HM.19.1AT NADPH-dependent xylose reductase (SpXYL1.1 gene) or the SpXYL2.2 gene from Spathaspora passalidarum strain UFMG-CM-Y474 in a Saccharomyces cerevisiae strain overexpressing the native XKS1 gene encoding xylulokinase, as well as being deleted in the alkaline phosphatase encoded by the PHO13 gene. Strains expressing the Spathaspora enzymes consumes xylose with xylitol as the major fermentation product. Higher specific growth rates, xylose consumption, and xylitol volumetric productivities are obtained by the co-expression of the SaXYL1 and SpXYL2.2 genes, when compared with the co-expression of the NADPH-dependent SpXYL1.1 xylose reductase. During glucose-xylose co-fermentation by the strain with co-expression of the SaXYL1 and SpXYL2.2 genes, both ethanol and xylitol are produced efficiently. Method development and evaluation, detailed overview
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