Metabolic re-engineering of Saccharomyces cerevisiae for the conversion of xylose to ethanol

Aristos Aristidou (Corresponding author), Mervi Toivari, Laura Ruohonen, Peter Richard, John Londesborough, Anita Teleman, Merja Penttilä

Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsScientific

Abstract

Lignocellulosic materials are such an abundant and inexpensive resource that existing suppliescould support the sustainable production of liquid transportation fuels. Xylose is the most abundant sugar in the hemicellulose (ca. 25% of dry weight) of hardwoods and crop residues, and it is thesecond only to glucose in natural abundance. Thus, the efficient utilization of the xylose component of hemicellulose offers the opportunity to significantly reduce the cost of bioethanol production.The yeastSaccharomyces cerevisiae, which is one of the most prominent ethanol producingorganisms from hexose sugars, has the drawback that it is unable to utilize pentose sugars.Our laboratory has genetically engineeredS. cerevisiae to utilize xylose by introducing the genesfor xylose reductase (XR) and xylulose dehydrogenase (XDH) fromPichia stipitis. These enzymes catalyze the sequential reduction of xylose to xylitoland oxidation of xylitol to xylulose[1].Although these strains could use xylose for growth and xylitol formation, ethanol production hasbeen rather poor. A primary reason for this poor yield has been attributed to redox cofactorimbalance. All known XDHenzymes are specific for NAD, whereas all known XR enzymes areeither specific for NADPH or have a preference for NADPH. Therefore, conversion of xylose toxylulose by this pathway results in the cellular pool of NADPH being converted to NADP and that of NAD being converted to NADH, after which further metabolism of xylose is greatly hindered.The NADH can be reoxidised under aerobic conditions, but this demands critical control of oxygenlevels to maintain fermentative metabolism and ethanol production. Recently, we have constructed different recombinant xylose utilizing S. cerevisiae strains, whichimprove xylose utilization. The first This has been achieved by the simultaneous expression of anNADH-specific glutamate dehydrogenase (GDH2) together with the primary NADPH-specific glutamate dehydrogenase (GDH1) thus creating a dual enzyme “transhydrogenase cycle”. Improvedxylose utilization and ethanol production rates we observed in batch and fed-batch cultivationswhen the GDH2 gene is overexpressed in axylose utilizing S. cerevisiae. An additionalimprovement in xylose to ethanol conversion came about by cloning and overexpressing theendogenous enzyme xylulokinase (XK), that phosphorylates xylulose to xylulose 5-phosphate.
Original languageEnglish
Title of host publicationProceedings of ESBES-2
Subtitle of host publication2nd European Symposium on Biochemical Engineering Science
EditorsSebastião Feyo de Azevedo, Eugénio C. Ferreira, Karel Ch.A.M. Luyben, Patricia Osseweijer
Place of PublicationPorto
Pages258
Publication statusPublished - 1998
Event2nd European Symposium on Biochemical Engineering Science, ESBES-2 - Porto, Portugal
Duration: 16 Sep 199819 Sep 1998

Conference

Conference2nd European Symposium on Biochemical Engineering Science, ESBES-2
Abbreviated titleESBES-2
CountryPortugal
CityPorto
Period16/09/9819/09/98

Fingerprint

xylose
Saccharomyces cerevisiae
engineering
ethanol
xylulose
NADP (coenzyme)
NAD (coenzyme)
ethanol production
xylitol
glutamate dehydrogenase
enzymes
sugars
hemicellulose
metabolism
pentoses
hexoses
aerobic conditions
crop residues
hardwood
molecular cloning

Cite this

Aristidou, A., Toivari, M., Ruohonen, L., Richard, P., Londesborough, J., Teleman, A., & Penttilä, M. (1998). Metabolic re-engineering of Saccharomyces cerevisiae for the conversion of xylose to ethanol. In S. F. de Azevedo, E. C. Ferreira, K. C. A. M. Luyben, & P. Osseweijer (Eds.), Proceedings of ESBES-2: 2nd European Symposium on Biochemical Engineering Science (pp. 258). Porto.
Aristidou, Aristos ; Toivari, Mervi ; Ruohonen, Laura ; Richard, Peter ; Londesborough, John ; Teleman, Anita ; Penttilä, Merja. / Metabolic re-engineering of Saccharomyces cerevisiae for the conversion of xylose to ethanol. Proceedings of ESBES-2: 2nd European Symposium on Biochemical Engineering Science. editor / Sebastião Feyo de Azevedo ; Eugénio C. Ferreira ; Karel Ch.A.M. Luyben ; Patricia Osseweijer. Porto, 1998. pp. 258
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abstract = "Lignocellulosic materials are such an abundant and inexpensive resource that existing suppliescould support the sustainable production of liquid transportation fuels. Xylose is the most abundant sugar in the hemicellulose (ca. 25{\%} of dry weight) of hardwoods and crop residues, and it is thesecond only to glucose in natural abundance. Thus, the efficient utilization of the xylose component of hemicellulose offers the opportunity to significantly reduce the cost of bioethanol production.The yeastSaccharomyces cerevisiae, which is one of the most prominent ethanol producingorganisms from hexose sugars, has the drawback that it is unable to utilize pentose sugars.Our laboratory has genetically engineeredS. cerevisiae to utilize xylose by introducing the genesfor xylose reductase (XR) and xylulose dehydrogenase (XDH) fromPichia stipitis. These enzymes catalyze the sequential reduction of xylose to xylitoland oxidation of xylitol to xylulose[1].Although these strains could use xylose for growth and xylitol formation, ethanol production hasbeen rather poor. A primary reason for this poor yield has been attributed to redox cofactorimbalance. All known XDHenzymes are specific for NAD, whereas all known XR enzymes areeither specific for NADPH or have a preference for NADPH. Therefore, conversion of xylose toxylulose by this pathway results in the cellular pool of NADPH being converted to NADP and that of NAD being converted to NADH, after which further metabolism of xylose is greatly hindered.The NADH can be reoxidised under aerobic conditions, but this demands critical control of oxygenlevels to maintain fermentative metabolism and ethanol production. Recently, we have constructed different recombinant xylose utilizing S. cerevisiae strains, whichimprove xylose utilization. The first This has been achieved by the simultaneous expression of anNADH-specific glutamate dehydrogenase (GDH2) together with the primary NADPH-specific glutamate dehydrogenase (GDH1) thus creating a dual enzyme “transhydrogenase cycle”. Improvedxylose utilization and ethanol production rates we observed in batch and fed-batch cultivationswhen the GDH2 gene is overexpressed in axylose utilizing S. cerevisiae. An additionalimprovement in xylose to ethanol conversion came about by cloning and overexpressing theendogenous enzyme xylulokinase (XK), that phosphorylates xylulose to xylulose 5-phosphate.",
author = "Aristos Aristidou and Mervi Toivari and Laura Ruohonen and Peter Richard and John Londesborough and Anita Teleman and Merja Penttil{\"a}",
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Aristidou, A, Toivari, M, Ruohonen, L, Richard, P, Londesborough, J, Teleman, A & Penttilä, M 1998, Metabolic re-engineering of Saccharomyces cerevisiae for the conversion of xylose to ethanol. in SF de Azevedo, EC Ferreira, KCAM Luyben & P Osseweijer (eds), Proceedings of ESBES-2: 2nd European Symposium on Biochemical Engineering Science. Porto, pp. 258, 2nd European Symposium on Biochemical Engineering Science, ESBES-2, Porto, Portugal, 16/09/98.

Metabolic re-engineering of Saccharomyces cerevisiae for the conversion of xylose to ethanol. / Aristidou, Aristos (Corresponding author); Toivari, Mervi; Ruohonen, Laura; Richard, Peter; Londesborough, John; Teleman, Anita; Penttilä, Merja.

Proceedings of ESBES-2: 2nd European Symposium on Biochemical Engineering Science. ed. / Sebastião Feyo de Azevedo; Eugénio C. Ferreira; Karel Ch.A.M. Luyben; Patricia Osseweijer. Porto, 1998. p. 258.

Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsScientific

TY - CHAP

T1 - Metabolic re-engineering of Saccharomyces cerevisiae for the conversion of xylose to ethanol

AU - Aristidou, Aristos

AU - Toivari, Mervi

AU - Ruohonen, Laura

AU - Richard, Peter

AU - Londesborough, John

AU - Teleman, Anita

AU - Penttilä, Merja

N1 - CA2: 1503 CA: BEL

PY - 1998

Y1 - 1998

N2 - Lignocellulosic materials are such an abundant and inexpensive resource that existing suppliescould support the sustainable production of liquid transportation fuels. Xylose is the most abundant sugar in the hemicellulose (ca. 25% of dry weight) of hardwoods and crop residues, and it is thesecond only to glucose in natural abundance. Thus, the efficient utilization of the xylose component of hemicellulose offers the opportunity to significantly reduce the cost of bioethanol production.The yeastSaccharomyces cerevisiae, which is one of the most prominent ethanol producingorganisms from hexose sugars, has the drawback that it is unable to utilize pentose sugars.Our laboratory has genetically engineeredS. cerevisiae to utilize xylose by introducing the genesfor xylose reductase (XR) and xylulose dehydrogenase (XDH) fromPichia stipitis. These enzymes catalyze the sequential reduction of xylose to xylitoland oxidation of xylitol to xylulose[1].Although these strains could use xylose for growth and xylitol formation, ethanol production hasbeen rather poor. A primary reason for this poor yield has been attributed to redox cofactorimbalance. All known XDHenzymes are specific for NAD, whereas all known XR enzymes areeither specific for NADPH or have a preference for NADPH. Therefore, conversion of xylose toxylulose by this pathway results in the cellular pool of NADPH being converted to NADP and that of NAD being converted to NADH, after which further metabolism of xylose is greatly hindered.The NADH can be reoxidised under aerobic conditions, but this demands critical control of oxygenlevels to maintain fermentative metabolism and ethanol production. Recently, we have constructed different recombinant xylose utilizing S. cerevisiae strains, whichimprove xylose utilization. The first This has been achieved by the simultaneous expression of anNADH-specific glutamate dehydrogenase (GDH2) together with the primary NADPH-specific glutamate dehydrogenase (GDH1) thus creating a dual enzyme “transhydrogenase cycle”. Improvedxylose utilization and ethanol production rates we observed in batch and fed-batch cultivationswhen the GDH2 gene is overexpressed in axylose utilizing S. cerevisiae. An additionalimprovement in xylose to ethanol conversion came about by cloning and overexpressing theendogenous enzyme xylulokinase (XK), that phosphorylates xylulose to xylulose 5-phosphate.

AB - Lignocellulosic materials are such an abundant and inexpensive resource that existing suppliescould support the sustainable production of liquid transportation fuels. Xylose is the most abundant sugar in the hemicellulose (ca. 25% of dry weight) of hardwoods and crop residues, and it is thesecond only to glucose in natural abundance. Thus, the efficient utilization of the xylose component of hemicellulose offers the opportunity to significantly reduce the cost of bioethanol production.The yeastSaccharomyces cerevisiae, which is one of the most prominent ethanol producingorganisms from hexose sugars, has the drawback that it is unable to utilize pentose sugars.Our laboratory has genetically engineeredS. cerevisiae to utilize xylose by introducing the genesfor xylose reductase (XR) and xylulose dehydrogenase (XDH) fromPichia stipitis. These enzymes catalyze the sequential reduction of xylose to xylitoland oxidation of xylitol to xylulose[1].Although these strains could use xylose for growth and xylitol formation, ethanol production hasbeen rather poor. A primary reason for this poor yield has been attributed to redox cofactorimbalance. All known XDHenzymes are specific for NAD, whereas all known XR enzymes areeither specific for NADPH or have a preference for NADPH. Therefore, conversion of xylose toxylulose by this pathway results in the cellular pool of NADPH being converted to NADP and that of NAD being converted to NADH, after which further metabolism of xylose is greatly hindered.The NADH can be reoxidised under aerobic conditions, but this demands critical control of oxygenlevels to maintain fermentative metabolism and ethanol production. Recently, we have constructed different recombinant xylose utilizing S. cerevisiae strains, whichimprove xylose utilization. The first This has been achieved by the simultaneous expression of anNADH-specific glutamate dehydrogenase (GDH2) together with the primary NADPH-specific glutamate dehydrogenase (GDH1) thus creating a dual enzyme “transhydrogenase cycle”. Improvedxylose utilization and ethanol production rates we observed in batch and fed-batch cultivationswhen the GDH2 gene is overexpressed in axylose utilizing S. cerevisiae. An additionalimprovement in xylose to ethanol conversion came about by cloning and overexpressing theendogenous enzyme xylulokinase (XK), that phosphorylates xylulose to xylulose 5-phosphate.

M3 - Conference abstract in proceedings

SN - 972-752-028-6

SP - 258

BT - Proceedings of ESBES-2

A2 - de Azevedo, Sebastião Feyo

A2 - Ferreira, Eugénio C.

A2 - Luyben, Karel Ch.A.M.

A2 - Osseweijer, Patricia

CY - Porto

ER -

Aristidou A, Toivari M, Ruohonen L, Richard P, Londesborough J, Teleman A et al. Metabolic re-engineering of Saccharomyces cerevisiae for the conversion of xylose to ethanol. In de Azevedo SF, Ferreira EC, Luyben KCAM, Osseweijer P, editors, Proceedings of ESBES-2: 2nd European Symposium on Biochemical Engineering Science. Porto. 1998. p. 258