Aerobic physiology of redox-engineered Saccharomyces cerevisiae strains modified in the ammonium assimilation for increased NADPH availability

FEMS Yeast Res. 2003 Oct;4(1):59-68. doi: 10.1016/S1567-1356(03)00155-7.


Recombinant strains altered in the ammonium assimilation pathways were constructed with the purpose of increasing NADPH availability. The NADPH-dependent glutamate dehydrogenase encoded by GDH1, which accounts for a major fraction of the NADPH consumption during growth on ammonium, was deleted, and alternative pathways for ammonium assimilation were overexpressed: GDH2 (NADH-consuming) or GLN1 and GLT1 (the GS-GOGAT system). The flux through the pentose phosphate pathway during aerobic growth on glucose decreased to about half that of the reference strain Saccharomyces cerevisiae CEN.PK113-7D, indicating a major redox alteration in the strains. The basic growth characteristics of the recombinant strains were not affected to a great extent, but the dilution rate at which the onset of aerobic fermentation occurred decreased, suggesting a relation between the onset of the Crabtree effect and the flux through the Embden-Meyerhof-Parnas pathway downstream of glucose 6-phosphate. No redox effect was observed in a strain containing a deletion of GLR1, encoding glutathione reductase, an enzyme that is NADPH-consuming.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerobiosis
  • Ammonia / metabolism*
  • Fermentation
  • Gene Expression
  • Genes, Fungal
  • Genetic Engineering
  • Glycolysis
  • NADP / metabolism*
  • Oxidation-Reduction
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae / physiology*


  • NADP
  • Ammonia