%0 Journal Article
%A Bartek, T.
%A Blombach, B.
%A Lang, S.
%A Eikmanns, B.J.
%A Wiechert, W.
%A Oldiges, M.
%A Nöh, K.
%A Noack, S.
%T Comparative 13C-metabolic flux analysis of pyruvate dehydrogenase complex-deficient L-valine-producing Corynebacterium glutamicum
%J Applied and environmental microbiology
%V 77
%@ 0099-2240
%C Washington, DC [u.a.]
%I Soc.
%M PreJuSER-15863
%P 6644 - 6652
%D 2011
%Z 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.
%X 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.
%K Carbon Dioxide: metabolism
%K Carbon Isotopes: metabolism
%K Corynebacterium glutamicum: genetics
%K Corynebacterium glutamicum: metabolism
%K Escherichia coli: enzymology
%K Escherichia coli: genetics
%K Escherichia coli Proteins: genetics
%K Escherichia coli Proteins: metabolism
%K Glycolysis
%K NADP Transhydrogenases: genetics
%K NADP Transhydrogenases: metabolism
%K Pentose Phosphate Pathway
%K Pyruvate Dehydrogenase Complex: genetics
%K Valine: metabolism
%K Carbon Isotopes (NLM Chemicals)
%K Escherichia coli Proteins (NLM Chemicals)
%K Pyruvate Dehydrogenase Complex (NLM Chemicals)
%K Carbon Dioxide (NLM Chemicals)
%K Valine (NLM Chemicals)
%K NADP Transhydrogenases (NLM Chemicals)
%K pntA protein, E coli (NLM Chemicals)
%K pntB protein, E coli (NLM Chemicals)
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:21784914
%2 pmc:PMC3187166
%U <Go to ISI:>//WOS:000294691400040
%R 10.1128/AEM.00575-11
%U https://juser.fz-juelich.de/record/15863