Metabolic Impact of Increased NADH Availability in Saccharomyces cerevisiae
Artikel i vetenskaplig tidskrift, 2010

Engineering the level of metabolic cofactors to manipulate metabolic flux is emerging as an attractive strategy for bioprocess applications. We present the metabolic consequences of increasing NADH in the cytosol and the mitochondria of Saccharomyces cerevisiae. In a strain that was disabled in formate metabolism, we either overexpressed the native NAD(+)-dependent formate dehydrogenase in the cytosol or directed it into the mitochondria by fusing it with the mitochondrial signal sequence encoded by the CYB2 gene. Upon exposure to formate, the mutant strains readily consumed formate and induced fermentative metabolism even under conditions of glucose derepression. Cytosolic overexpression of formate dehydrogenase resulted in the production of glycerol, while when this enzyme was directed into the mitochondria, we observed glycerol and ethanol production. Clearly, these results point toward different patterns of compartmental regulation of redox homeostasis. When pulsed with formate, S. cerevisiae cells growing in a steady state on glucose immediately consumed formate. However, formate consumption ceased after 20 min. Our analysis revealed that metabolites at key branch points of metabolic pathways were affected the most by the genetic perturbations and that the intracellular concentrations of sugar phosphates were specifically affected by time. In conclusion, the results have implications for the design of metabolic networks in yeast for industrial applications.

chromatography

candida-utilis

respiratory-chain

formate dehydrogenase

energy-source

glucose

additional

yeast

mitochondrial outer-membrane

limited chemostat cultures

carboxylic-acids

Författare

J. Hou

Shandong University

Gionata Scalcinati

Chalmers University of Technology

M. Oldiges

Forschungszentrum Jülich

Goutham Vemuri

Chalmers, Kemi- och bioteknik, Livsvetenskaper, Systembiologi

Applied and Environmental Microbiology

0099-2240 (ISSN) 1098-5336 (eISSN)

Vol. 76 851-859

Ämneskategorier

Industriell bioteknik

DOI

10.1128/AEM.02040-09