1.1.1.307: D-xylose reductase [NAD(P)H]
This is an abbreviated version!
For detailed information about D-xylose reductase [NAD(P)H], go to the full flat file.
Word Map on EC 1.1.1.307
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1.1.1.307
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synthesis
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l-arabinose
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stipitis
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kluyveromyces
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marxianus
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oxygen-limited
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nadph-linked
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reesei
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l-arabitol
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trichoderma
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passalidarum
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scheffersomyces
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spathaspora
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jecorina
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pachysolen
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pentitols
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bioethanol
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hypocrea
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tannophilus
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galactitol
- 1.1.1.307
- synthesis
- l-arabinose
- stipitis
-
kluyveromyces
- marxianus
-
oxygen-limited
-
nadph-linked
- reesei
- l-arabitol
- trichoderma
- passalidarum
-
scheffersomyces
- spathaspora
- jecorina
-
pachysolen
- pentitols
-
bioethanol
- hypocrea
- tannophilus
- galactitol
Reaction
Synonyms
AKR2B5, ALR2, CTHT_0056950, CtXR, dsXR, dual specific xylose reductase, KmXYL1, NAD(P)H-dependent D-xylose reductase, NAD(P)H-dependent D-xylose reductase-like protein, NAD(P)H-dependent XR, NAD(P)H-dependent xylose reductase, NAD(P)H-linked xylose reductase, NADH/NADPH-xylose reductase, NADP-dependent xylose reductase, PsXR, PsXYL1, SaXYL1, SpXYL1.1, SsXR, Texr, XR, XYL1, xylose reductase, XylR, XyrA
ECTree
1.1.1.307 D-xylose reductase [NAD(P)H]Advanced search results
results (
results (Engineering
Engineering on EC 1.1.1.307 - D-xylose reductase [NAD(P)H]
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PROTEIN VARIANTS 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
C36Y
K271R/N273D
K274M
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site-directed mutagenesis, the mutant enzyme shows increased activity and altered kinetics compared to the wild-type enzyme
K74M/N276D
-
site-directed mutagenesis, the mutant enzyme shows increased activity and altered kinetics compared to the wild-type enzyme
N272D
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site-directed mutagenesis, results in strain TMB 3422, the mutation enables the yeast for anaerobic growth on xylose displayed higher aerobic growth rates
N272D/P275Q
-
site-directed mutagenesis, results in strain TMB 3421, the mutations enable the yeast for anaerobic growth on xylose displayed higher aerobic growth rates
N276D
-
site-directed mutagenesis, the mutant enzyme shows increased activity and altered kinetics compared to the wild-type enzyme
P275Q
-
site-directed mutagenesis, results in strain TMB 3423, the mutation enables the yeast for anaerobic growth on xylose displayed higher aerobic growth rates
N272D
-
site-directed mutagenesis, results in strain TMB 3422, the mutation enables the yeast for anaerobic growth on xylose displayed higher aerobic growth rates
-
N272D/P275Q
-
site-directed mutagenesis, results in strain TMB 3421, the mutations enable the yeast for anaerobic growth on xylose displayed higher aerobic growth rates
-
P275Q
-
site-directed mutagenesis, results in strain TMB 3423, the mutation enables the yeast for anaerobic growth on xylose displayed higher aerobic growth rates
-
K21A/N272D
catalytic efficiency is almost 9fold that of the K21A mutant and 2fold that of the wild-type enzyme. Strong preference for NADH over NADPH
K270M
-
mutation results in a significant increase in the Km values for both NADPH and NADH. The kinetic parameters for the NADH-linked reaction catalyzed by the K270M mutant could not even be determined since this mutant could not be saturated with NADH
K270R
-
mutation increases the Km value for NADPH 25fold, while the Km for NADH only increased two-fold
K270S/N272P/S271G/R276F
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the mutant shows a 25fold preference toward NADH over NADPH by a factor of about 13fold, or an improvement of about 42fold, as measured by the ratio of the specificity constant kcat/Km coenzyme. Compared with the wild-type, the kcat(NADH) is slightly lower, while the kcat(NADPH) decreases by a factor of about 10
K274G
mutant shows an increase in NADH versus NADPH selectivity with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity
K274M
mutant shows an increase in NADH versus NADPH selectivity with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity
K274R
mutant shows an increase in NADH versus NADPH selectivity with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity
K274R/N276D
mutant shows an increase in NADH versus NADPH selectivity with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity. Mutant exhibits a 5fold preference for NADH over NADPH
N276D
mutant shows an increase in NADH versus NADPH selectivity with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity
R280H
mutant shows an increase in NADH versus NADPH selectivity with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity
S275A
mutant shows an increase in NADH versus NADPH selectivity with only modest alterations of the original NADH-linked xylose specificity and catalytic-centre activity
additional information
C36Y
about 2fold increase in activity. The ratios of NADH-linked and NADPH-linked activities are changed from 1.92 to 1.30
C36Y
-
about 2fold increase in activity. The ratios of NADH-linked and NADPH-linked activities are changed from 1.92 to 1.30
-
K271R/N273D
in the double mutant, affinity for NADPH decreases 3.1fold, while affinity for NADH remains relatively unchanged in comparison with the wild-type enzyme. The turnover number increases 1.6fold for the double mutant with NADH and decreases 3.2fold with NADPH relative to the wild-type enzyme. As a consequence, the catalytic efficiency of the double mutant (kcat/Km) increases 1.4fold with NADH and decreases 10.8fold with NADPH relative to the wild-type enzyme. Using the specificity constant (kcat/Km (NADH)/kcat/Km(NADPH)) the coenzyme preference for NADH is improved 16fold in the TeXR K271R/N273D double-mutant enzyme
K271R/N273D
catalytic efficiency of the double mutant increases 1.4fold with NADH and decreases 10.8fold with NADPH relative to the wild-type enzyme
additional information
-
xylitol production is increased by expression of codon-optimized Neurospora crassa xylose reductase gene under control of a constitutive glyceraldehyde-3-phosphate dehydrogenase promoter in a Candida tropicalis xylitol dehydrogenase gene (XYL2)-disrupted strain resulting in recombinant strain LNG2, overview
additional information
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xylitol production is increased by expression of codon-optimized Neurospora crassa xylose reductase gene under control of a constitutive glyceraldehyde-3-phosphate dehydrogenase promoter in a Candida tropicalis xylitol dehydrogenase gene (XYL2)-disrupted strain resulting in recombinant strain LNG2, overview
-
additional information
simultaneous optimization of xylose reductase activity and stability using statistical methods is effective as compared to optimisation of the parameters separately, effects of pH and temperature on the activity and stability of xylose reductase from Debaryomyces nepalensis NCYC 3413 are investigated by enzyme assays, and independent variables are optimised using surface response methodology. Enzyme activity and stability are optimised separately and concurrently to decipher the appropriate conditions, method comparisons, overview. Optimized conditions are pH 7.1 and 27°C with predicted responses of specific activity of 72.3 U/mg and half-life time of 566 min. The experimental values (specific activity 50.2 U/mg, half-life time 818 min) are on par with predicted values indicating the significance of the model
additional information
-
simultaneous optimization of xylose reductase activity and stability using statistical methods is effective as compared to optimisation of the parameters separately, effects of pH and temperature on the activity and stability of xylose reductase from Debaryomyces nepalensis NCYC 3413 are investigated by enzyme assays, and independent variables are optimised using surface response methodology. Enzyme activity and stability are optimised separately and concurrently to decipher the appropriate conditions, method comparisons, overview. Optimized conditions are pH 7.1 and 27°C with predicted responses of specific activity of 72.3 U/mg and half-life time of 566 min. The experimental values (specific activity 50.2 U/mg, half-life time 818 min) are on par with predicted values indicating the significance of the model
-
additional information
construction of the engineered Kluyveromyces marxianus strain 17555-JBP2 by random multi-copy integration of the mutated KmXYL1 gene exhibits two more copies of mKmXY1 genes and a 9.63fold elevation in transcription of NAD(P)H-dependent XR, optimization of bioreactor fermentation conditions (agitation speed), high-temperature (40°C) xylitol productivity of strain 17555-JBP2, which then shows an 81% improvement relative to the parental strain. Method development and optimization, overview
additional information
-
construction of the engineered Kluyveromyces marxianus strain 17555-JBP2 by random multi-copy integration of the mutated KmXYL1 gene exhibits two more copies of mKmXY1 genes and a 9.63fold elevation in transcription of NAD(P)H-dependent XR, optimization of bioreactor fermentation conditions (agitation speed), high-temperature (40°C) xylitol productivity of strain 17555-JBP2, which then shows an 81% improvement relative to the parental strain. Method development and optimization, overview
additional information
-
construction of the engineered Kluyveromyces marxianus strain 17555-JBP2 by random multi-copy integration of the mutated KmXYL1 gene exhibits two more copies of mKmXY1 genes and a 9.63fold elevation in transcription of NAD(P)H-dependent XR, optimization of bioreactor fermentation conditions (agitation speed), high-temperature (40°C) xylitol productivity of strain 17555-JBP2, which then shows an 81% improvement relative to the parental strain. Method development and optimization, overview
-
additional information
-
construction of the engineered Kluyveromyces marxianus strain 17555-JBP2 by random multi-copy integration of the mutated KmXYL1 gene exhibits two more copies of mKmXY1 genes and a 9.63fold elevation in transcription of NAD(P)H-dependent XR, optimization of bioreactor fermentation conditions (agitation speed), high-temperature (40°C) xylitol productivity of strain 17555-JBP2, which then shows an 81% improvement relative to the parental strain. Method development and optimization, overview
-
additional information
-
construction of the engineered Kluyveromyces marxianus strain 17555-JBP2 by random multi-copy integration of the mutated KmXYL1 gene exhibits two more copies of mKmXY1 genes and a 9.63fold elevation in transcription of NAD(P)H-dependent XR, optimization of bioreactor fermentation conditions (agitation speed), high-temperature (40°C) xylitol productivity of strain 17555-JBP2, which then shows an 81% improvement relative to the parental strain. Method development and optimization, overview
-
additional information
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh
additional information
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recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh
-
additional information
-
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh
-
additional information
-
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh
-
additional information
-
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh
-
additional information
-
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh
-
additional information
cells of recombinant Escherichia coli strain BL21(DE3)/pCDFDuet-1-XR-GDH coexpressing xylose reductase (XR) and glucose dehydrogenase (GDH) are immobilized and applied for the production of xylitol from xylose mother liquor (XML). Various immobilization methods are screened and the cross-linking approach with diatomite and polyetherimide as the raw materials and glutaraldehyde as the cross-linking agent is the optimal one, and the recovery activity reached of 80.3% after immobilization. The half-life of immobilized cells is 1.52times to that of free cells. Batch experiments show that the enzyme activity of immobilized cells remains 70.5% of initial activity after 10 batches and the space-time yield of xylitol reaches of 11.5 g/l/h. Method development and optimization, overview
additional information
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coenzyme specificities of the NADPH-preferring xylose reductase and the NAD+-dependent xylitol dehydrogenase, EC 1.1.1.9, 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 improved performance in xylose fermentation
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, XYL2 (EC 1.1.1.9), 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
enhanced production of xylitol from xylose by expression of Bacillus subtilis arabinose:H+ symporter and Scheffersomyces stipitis xylose reductase in recombinant Saccharomyces cerevisiae
additional information
recombinant enzyme expression in differently engineered Saccharomyces cerevisiae strains SCF201 and SCF202, aerobic or anaerobic batch fermentation cultures, measurement of xylitol consumption and ethanol production, analysis of culture condition effects, overview
additional information
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh, the biotransformation is very efficient with as high as 80% w/w conversion within two hours. The whole cells can be reused for multiple rounds of catalysis without loss of activity. The cells can directly transform D-xylose in a non-detoxified hemicelluloses hydrolysate to xylitol at 70% w/w yield. Recombinant Pichia pastoris expressing xylose reductase could transform D-xylose, either in pure form or in crude hemicelluloses hydrolysate, to bio-xylitol very efficiently. This biocatalytic reaction happens without the external addition of any NAD(P)H, NAD(P)+, and auxiliary substrate as an electron donor. PsXYL1 in the cells is not inhibited by D-xylose up to 1.5 M. About 320 mM xylitol is produced from 400 mM D-xylose (80% conversion), 535 mM xylitol from 750 mM D-xylose (71% conversion), but only about 750 mM xylitol from 1.5 M D-xylose (50% conversion). The reaction with 1.5 M of D-xylose should not be limited by NAD+ since the cells are not recycled
additional information
xylitol is produced from lignocellulosic biomass by a recombinant strain of Saccharomyces cerevisiae strain YPH499-SsXR-AaBGL expressing cytosolic Scheffersomyces stipitis xylose reductase (SsXR), along with Aspergillus aculeatus beta-glucosidase 1 (AaBGL) displayed on the cell surface. The simultaneous co-fermentation of cellobiose/xylose by this strain leads to an about 2.5fold increase in xylitol/xylose ratio compared to the use of a glucose/xylose mixture as a substrate. Further improvement in the xylose uptake by the cell is achieved by a broad evaluation of several homologous and heterologous transporters. Homologous maltose transporter (ScMAL11) shows the best performance in xylose transport and is used to generate the strain YPH499-XRScMAL11-BGL with a significantly improved xylitol production capacity from cellobiose/xylose co-utilization. Method evaluation and optimization, overview
additional information
xylose isomerase (XI, EC 5.3.1.5) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways are used to confer xylose assimilation capacity to Saccharomyces cerevisiae for achievement of economically viable lignocellulosic ethanol production. XI and/or XR/XDH pathways are introduced into two robust industrial Saccharomyces cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate, and the results are correlated with the differential enzyme activities found in the xylose-pathway engineered strains. 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. 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%. An advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose is proven
additional information
-
recombinant enzyme expression in differently engineered Saccharomyces cerevisiae strains SCF201 and SCF202, aerobic or anaerobic batch fermentation cultures, measurement of xylitol consumption and ethanol production, analysis of culture condition effects, overview
-
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, XYL2 (EC 1.1.1.9), 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
-
xylitol is produced from lignocellulosic biomass by a recombinant strain of Saccharomyces cerevisiae strain YPH499-SsXR-AaBGL expressing cytosolic Scheffersomyces stipitis xylose reductase (SsXR), along with Aspergillus aculeatus beta-glucosidase 1 (AaBGL) displayed on the cell surface. The simultaneous co-fermentation of cellobiose/xylose by this strain leads to an about 2.5fold increase in xylitol/xylose ratio compared to the use of a glucose/xylose mixture as a substrate. Further improvement in the xylose uptake by the cell is achieved by a broad evaluation of several homologous and heterologous transporters. Homologous maltose transporter (ScMAL11) shows the best performance in xylose transport and is used to generate the strain YPH499-XRScMAL11-BGL with a significantly improved xylitol production capacity from cellobiose/xylose co-utilization. Method evaluation and optimization, overview
-
additional information
-
enhanced production of xylitol from xylose by expression of Bacillus subtilis arabinose:H+ symporter and Scheffersomyces stipitis xylose reductase in recombinant Saccharomyces cerevisiae
-
additional information
-
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh, the biotransformation is very efficient with as high as 80% w/w conversion within two hours. The whole cells can be reused for multiple rounds of catalysis without loss of activity. The cells can directly transform D-xylose in a non-detoxified hemicelluloses hydrolysate to xylitol at 70% w/w yield. Recombinant Pichia pastoris expressing xylose reductase could transform D-xylose, either in pure form or in crude hemicelluloses hydrolysate, to bio-xylitol very efficiently. This biocatalytic reaction happens without the external addition of any NAD(P)H, NAD(P)+, and auxiliary substrate as an electron donor. PsXYL1 in the cells is not inhibited by D-xylose up to 1.5 M. About 320 mM xylitol is produced from 400 mM D-xylose (80% conversion), 535 mM xylitol from 750 mM D-xylose (71% conversion), but only about 750 mM xylitol from 1.5 M D-xylose (50% conversion). The reaction with 1.5 M of D-xylose should not be limited by NAD+ since the cells are not recycled
-
additional information
-
xylose isomerase (XI, EC 5.3.1.5) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways are used to confer xylose assimilation capacity to Saccharomyces cerevisiae for achievement of economically viable lignocellulosic ethanol production. XI and/or XR/XDH pathways are introduced into two robust industrial Saccharomyces cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate, and the results are correlated with the differential enzyme activities found in the xylose-pathway engineered strains. 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. 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%. An advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose is proven
-
additional information
-
recombinant enzyme expression in differently engineered Saccharomyces cerevisiae strains SCF201 and SCF202, aerobic or anaerobic batch fermentation cultures, measurement of xylitol consumption and ethanol production, analysis of culture condition effects, overview
-
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, XYL2 (EC 1.1.1.9), 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
-
xylitol is produced from lignocellulosic biomass by a recombinant strain of Saccharomyces cerevisiae strain YPH499-SsXR-AaBGL expressing cytosolic Scheffersomyces stipitis xylose reductase (SsXR), along with Aspergillus aculeatus beta-glucosidase 1 (AaBGL) displayed on the cell surface. The simultaneous co-fermentation of cellobiose/xylose by this strain leads to an about 2.5fold increase in xylitol/xylose ratio compared to the use of a glucose/xylose mixture as a substrate. Further improvement in the xylose uptake by the cell is achieved by a broad evaluation of several homologous and heterologous transporters. Homologous maltose transporter (ScMAL11) shows the best performance in xylose transport and is used to generate the strain YPH499-XRScMAL11-BGL with a significantly improved xylitol production capacity from cellobiose/xylose co-utilization. Method evaluation and optimization, overview
-
additional information
-
enhanced production of xylitol from xylose by expression of Bacillus subtilis arabinose:H+ symporter and Scheffersomyces stipitis xylose reductase in recombinant Saccharomyces cerevisiae
-
additional information
-
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh, the biotransformation is very efficient with as high as 80% w/w conversion within two hours. The whole cells can be reused for multiple rounds of catalysis without loss of activity. The cells can directly transform D-xylose in a non-detoxified hemicelluloses hydrolysate to xylitol at 70% w/w yield. Recombinant Pichia pastoris expressing xylose reductase could transform D-xylose, either in pure form or in crude hemicelluloses hydrolysate, to bio-xylitol very efficiently. This biocatalytic reaction happens without the external addition of any NAD(P)H, NAD(P)+, and auxiliary substrate as an electron donor. PsXYL1 in the cells is not inhibited by D-xylose up to 1.5 M. About 320 mM xylitol is produced from 400 mM D-xylose (80% conversion), 535 mM xylitol from 750 mM D-xylose (71% conversion), but only about 750 mM xylitol from 1.5 M D-xylose (50% conversion). The reaction with 1.5 M of D-xylose should not be limited by NAD+ since the cells are not recycled
-
additional information
-
xylose isomerase (XI, EC 5.3.1.5) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways are used to confer xylose assimilation capacity to Saccharomyces cerevisiae for achievement of economically viable lignocellulosic ethanol production. XI and/or XR/XDH pathways are introduced into two robust industrial Saccharomyces cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate, and the results are correlated with the differential enzyme activities found in the xylose-pathway engineered strains. 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. 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%. An advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose is proven
-
additional information
-
recombinant enzyme expression in differently engineered Saccharomyces cerevisiae strains SCF201 and SCF202, aerobic or anaerobic batch fermentation cultures, measurement of xylitol consumption and ethanol production, analysis of culture condition effects, overview
-
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, XYL2 (EC 1.1.1.9), 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
-
xylitol is produced from lignocellulosic biomass by a recombinant strain of Saccharomyces cerevisiae strain YPH499-SsXR-AaBGL expressing cytosolic Scheffersomyces stipitis xylose reductase (SsXR), along with Aspergillus aculeatus beta-glucosidase 1 (AaBGL) displayed on the cell surface. The simultaneous co-fermentation of cellobiose/xylose by this strain leads to an about 2.5fold increase in xylitol/xylose ratio compared to the use of a glucose/xylose mixture as a substrate. Further improvement in the xylose uptake by the cell is achieved by a broad evaluation of several homologous and heterologous transporters. Homologous maltose transporter (ScMAL11) shows the best performance in xylose transport and is used to generate the strain YPH499-XRScMAL11-BGL with a significantly improved xylitol production capacity from cellobiose/xylose co-utilization. Method evaluation and optimization, overview
-
additional information
-
enhanced production of xylitol from xylose by expression of Bacillus subtilis arabinose:H+ symporter and Scheffersomyces stipitis xylose reductase in recombinant Saccharomyces cerevisiae
-
additional information
-
recombinant enzyme expression in Pichia pastoris, coexpression with Bacillus subtilis gene gdh, the biotransformation is very efficient with as high as 80% w/w conversion within two hours. The whole cells can be reused for multiple rounds of catalysis without loss of activity. The cells can directly transform D-xylose in a non-detoxified hemicelluloses hydrolysate to xylitol at 70% w/w yield. Recombinant Pichia pastoris expressing xylose reductase could transform D-xylose, either in pure form or in crude hemicelluloses hydrolysate, to bio-xylitol very efficiently. This biocatalytic reaction happens without the external addition of any NAD(P)H, NAD(P)+, and auxiliary substrate as an electron donor. PsXYL1 in the cells is not inhibited by D-xylose up to 1.5 M. About 320 mM xylitol is produced from 400 mM D-xylose (80% conversion), 535 mM xylitol from 750 mM D-xylose (71% conversion), but only about 750 mM xylitol from 1.5 M D-xylose (50% conversion). The reaction with 1.5 M of D-xylose should not be limited by NAD+ since the cells are not recycled
-
additional information
-
xylose isomerase (XI, EC 5.3.1.5) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways are used to confer xylose assimilation capacity to Saccharomyces cerevisiae for achievement of economically viable lignocellulosic ethanol production. XI and/or XR/XDH pathways are introduced into two robust industrial Saccharomyces cerevisiae strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate, and the results are correlated with the differential enzyme activities found in the xylose-pathway engineered strains. 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. 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%. An advantage of using the XI from Clostridium phytofermentans to attain high ethanol productivities and yields from xylose is proven
-
additional information
-
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 arborariae 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
Spathaspora arborariae UFMG-HM.19.1AT
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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 arborariae 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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