Applied Microbiology and Biotechnology

, Volume 95, Issue 4, pp 1001–1010

Physiological characterization of recombinant Saccharomyces cerevisiae expressing the Aspergillus nidulans phosphoketolase pathway: validation of activity through 13C-based metabolic flux analysis

  • Marta Papini
  • Intawat Nookaew
  • Verena Siewers
  • Jens Nielsen
Applied microbial and cell physiology

DOI: 10.1007/s00253-012-3936-0

Cite this article as:
Papini, M., Nookaew, I., Siewers, V. et al. Appl Microbiol Biotechnol (2012) 95: 1001. doi:10.1007/s00253-012-3936-0

Abstract

Several bacterial species and filamentous fungi utilize the phosphoketolase pathway (PHK) for glucose dissimilation as an alternative to the Embden–Meyerhof–Parnas pathway. In Aspergillus nidulans, the utilization of this metabolic pathway leads to increased carbon flow towards acetate and acetyl CoA. In the first step of the PHK, the pentose phosphate pathway intermediate xylulose-5-phosphate is converted into acetylphosphate and glyceraldehyde-3-phosphate through the action of xylulose-5-phosphate phosphoketolase, and successively acetylphosphate is converted into acetate by the action of acetate kinase. In the present work, we describe a metabolic engineering strategy used to express the fungal genes of the phosphoketolase pathway in Saccharomyces cerevisiae and the effects of the expression of this recombinant route in yeast. The phenotype of the engineered yeast strain MP003 was studied during batch and chemostat cultivations, showing a reduced biomass yield and an increased acetate yield during batch cultures. To establish whether the observed effects in the recombinant strain MP003 were due directly or indirectly to the expression of the phosphoketolase pathway, we resolved the intracellular flux distribution based on 13C labeling during chemostat cultivations. From flux analysis it is possible to conclude that yeast is able to use the recombinant pathway. Our work indicates that the utilization of the phosphoketolase pathway does not interfere with glucose assimilation through the Embden–Meyerhof–Parnas pathway and that the expression of this route can contribute to increase the acetyl CoA supply, therefore holding potential for future metabolic engineering strategies having acetyl CoA as precursor for the biosynthesis of industrially relevant compounds.

Keywords

PhosphoketolaseMetabolic engineering13C-based metabolic flux analysisAcetyl CoA supplyGlycolysis

Supplementary material

253_2012_3936_MOESM1_ESM.docx (13 kb)
Supplementary 1DOCX 13 kb

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Marta Papini
    • 1
  • Intawat Nookaew
    • 1
  • Verena Siewers
    • 1
  • Jens Nielsen
    • 1
  1. 1.Department of Chemical and Biological EngineeringChalmers University of TechnologyGothenburgSweden