1. Academic Validation
  2. Enhancing the flux of D-glucose to the pentose phosphate pathway in Saccharomyces cerevisiae for the production of D-ribose and ribitol

Enhancing the flux of D-glucose to the pentose phosphate pathway in Saccharomyces cerevisiae for the production of D-ribose and ribitol

  • Appl Microbiol Biotechnol. 2010 Jan;85(3):731-9. doi: 10.1007/s00253-009-2184-4.
Mervi H Toivari 1 Hannu Maaheimo Merja Penttilä Laura Ruohonen
Affiliations

Affiliation

  • 1 VTT Technical Research Centre of Finland, Espoo, Finland. Mervi.Toivari@vtt.fi
Abstract

Phosphoglucose isomerase-deficient (pgi1) strains of Saccharomyces cerevisiae were studied for the production of D-ribose and ribitol from D-glucose via the intermediates of the pentose phosphate pathway. Overexpression of the genes coding for NAD(+)-specific glutamate dehydrogenase (GDH2) of S. cerevisiae or NADPH-utilising glyceraldehyde-3-phosphate dehydrogenase (gapB) of Bacillus subtilis enabled growth of the pgi1 mutant strains on D-glucose. Overexpression of the gene encoding sugar phosphate Phosphatase (DOG1) of S. cerevisiae was needed for the production of D-ribose and ribitol; however, it reduced the growth of the pgi1 strains expressing GDH2 or gapB in the presence of higher D-glucose concentrations. The CEN.PK2-1D laboratory strain expressing both gapB and DOG1 produced approximately 0.4 g l(-1) of D-ribose and ribitol when grown on 20 g l(-1) (w/v) D-fructose with 4 g l(-1) (w/v) D-glucose. Nuclear magnetic resonance measurements of the cells grown with (13)C-labelled D-glucose showed that about 60% of the D-ribose produced was derived from D-glucose. Strains deficient in both phosphoglucose isomerase and Transketolase activities, and expressing DOG1 and GDH2 tolerated only low D-glucose concentrations (< or =2 g l(-1) (w/v)), but produced 1 g l(-1) (w/v) D-ribose and ribitol when grown on 20 g l(-1) (w/v) D-fructose with 2 g l(-1) (w/v) D-glucose.

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