Journal Article

PreJuSER-15863

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Comparative 13C-metabolic flux analysis of pyruvate dehydrogenase complex-deficient L-valine-producing Corynebacterium glutamicum

Bartek, T.FZJ* ; Blombach, B. ; Lang, S. ; Eikmanns, B. J. ; Wiechert, W.FZJ* ; Oldiges, M.FZJ* ; Nöh, K.FZJ* ; Noack, S.FZJ*

2011
Soc. Washington, DC [u.a.]

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Please use a persistent id in citations: doi:10.1128/AEM.00575-11

Abstract: L-Valine can be formed successfully using C. glutamicum strains missing an active pyruvate dehydrogenase enzyme complex (PDHC). Wild-type C. glutamicum and four PDHC-deficient strains were compared by (13)C metabolic flux analysis, especially focusing on the split ratio between glycolysis and the pentose phosphate pathway (PPP). Compared to the wild type, showing a carbon flux of 69% ± 14% through the PPP, a strong increase in the PPP flux was observed in PDHC-deficient strains with a maximum of 113% ± 22%. The shift in the split ratio can be explained by an increased demand of NADPH for l-valine formation. In accordance, the introduction of the Escherichia coli transhydrogenase PntAB, catalyzing the reversible conversion of NADH to NADPH, into an L-valine-producing C. glutamicum strain caused the PPP flux to decrease to 57% ± 6%, which is below the wild-type split ratio. Hence, transhydrogenase activity offers an alternative perspective for sufficient NADPH supply, which is relevant for most amino acid production systems. Moreover, as demonstrated for L-valine, this bypass leads to a significant increase of product yield due to a concurrent reduction in carbon dioxide formation via the PPP.

Keyword(s): Carbon Dioxide: metabolism (MeSH) ; Carbon Isotopes: metabolism (MeSH) ; Corynebacterium glutamicum: genetics (MeSH) ; Corynebacterium glutamicum: metabolism (MeSH) ; Escherichia coli: enzymology (MeSH) ; Escherichia coli: genetics (MeSH) ; Escherichia coli Proteins: genetics (MeSH) ; Escherichia coli Proteins: metabolism (MeSH) ; Glycolysis (MeSH) ; NADP Transhydrogenases: genetics (MeSH) ; NADP Transhydrogenases: metabolism (MeSH) ; Pentose Phosphate Pathway (MeSH) ; Pyruvate Dehydrogenase Complex: genetics (MeSH) ; Valine: metabolism (MeSH) ; Carbon Isotopes ; Escherichia coli Proteins ; Pyruvate Dehydrogenase Complex ; Carbon Dioxide ; Valine ; NADP Transhydrogenases ; pntA protein, E coli ; pntB protein, E coli ; J

Note: This work was financially supported by the Fachagentur Nachwachsende Rohstoffe (Agency for Renewable Resources) of the BMVEL, German Federal Ministry of Food, Agriculture and Consumer Protection (grant 04NR003/22000304), and by Evonik Degussa GmbH.

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Contributing Institute(s):

1. Biotechnologie 2 (IBT-2)

Research Program(s):

1. Biotechnologie (PBT)

Appears in the scientific report 2011

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