This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Roca, C.
Right arrow Articles by Olsson, L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Roca, C.
Right arrow Articles by Olsson, L.
Agricola
Right arrow Articles by Roca, C.
Right arrow Articles by Olsson, L.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, August 2003, p. 4732-4736, Vol. 69, No. 8
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.8.4732-4736.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Metabolic Engineering of Ammonium Assimilation in Xylose-Fermenting Saccharomyces cerevisiae Improves Ethanol Production

Christophe Roca, Jens Nielsen, and Lisbeth Olsson*

Center for Process Biotechnology, BioCentrum-DTU, Technical University of Denmark, 2800 Kongens Lyngby, Denmark

Received 28 February 2003/ Accepted 2 June 2003

Cofactor imbalance impedes xylose assimilation in Saccharomyces cerevisiae that has been metabolically engineered for xylose utilization. To improve cofactor use, we modified ammonia assimilation in recombinant S. cerevisiae by deleting GDH1, which encodes an NADPH-dependent glutamate dehydrogenase, and by overexpressing either GDH2, which encodes an NADH-dependent glutamate dehydrogenase, or GLT1 and GLN1, which encode the GS-GOGAT complex. Overexpression of GDH2 increased ethanol yield from 0.43 to 0.51 mol of carbon (Cmol) Cmol-1, mainly by reducing xylitol excretion by 44%. Overexpression of the GS-GOGAT complex did not improve conversion of xylose to ethanol during batch cultivation, but it increased ethanol yield by 16% in carbon-limited continuous cultivation at a low dilution rate.

* Corresponding author. Mailing address: Center for Process Biotechnology, BioCentrum-DTU, Building 223, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. Phone: 45 4525 2677. Fax: 45 4588 4148. E-mail: lo{at}biocentrum.dtu.dk.

Applied and Environmental Microbiology, August 2003, p. 4732-4736, Vol. 69, No. 8
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.8.4732-4736.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Watanabe, S., Abu Saleh, A., Pack, S. P., Annaluru, N., Kodaki, T., Makino, K. (2007). Ethanol production from xylose by recombinant Saccharomyces cerevisiae expressing protein-engineered NADH-preferring xylose reductase from Pichia stipitis. Microbiology 153: 3044-3054 [Abstract] [Full Text]  
  • Petschacher, B., Nidetzky, B. (2005). Engineering Candida tenuis Xylose Reductase for Improved Utilization of NADH: Antagonistic Effects of Multiple Side Chain Replacements and Performance of Site-Directed Mutants under Simulated In Vivo Conditions. Appl. Environ. Microbiol. 71: 6390-6393 [Abstract] [Full Text]  
  • Sonderegger, M., Schumperli, M., Sauer, U. (2004). Metabolic Engineering of a Phosphoketolase Pathway for Pentose Catabolism in Saccharomyces cerevisiae. Appl. Environ. Microbiol. 70: 2892-2897 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»