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.
%0 Journal Article
%1 bartek_comparative_2011
%A Bartek, Tobias
%A Blombach, Bastian
%A Lang, Siegmund
%A Eikmanns, Bernhard J.
%A Wiechert, Wolfgang
%A Oldiges, Marco
%A Nöh, Katharina
%A Noack, Stephan
%D 2011
%J Appl. Environ. Microbiol.
%K Carbon Complex, Corynebacterium Dehydrogenase Dioxide, Escherichia Glycolysis, Isotopes, NADP Pathway, Pentose Phosphate Proteins, Pyruvate Transhydrogenases Valine, coli coli, glutamicum, myown
%N 18
%P 6644--6652
%R 10.1128/AEM.00575-11
%T Comparative 13C metabolic flux analysis of pyruvate dehydrogenase complex-deficient, L-valine-producing Corynebacterium glutamicum
%V 77
%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.
@article{bartek_comparative_2011,
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.},
added-at = {2018-02-09T13:18:17.000+0100},
author = {Bartek, Tobias and Blombach, Bastian and Lang, Siegmund and Eikmanns, Bernhard J. and Wiechert, Wolfgang and Oldiges, Marco and Nöh, Katharina and Noack, Stephan},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/287adbada4c59b528370d7ee2b0a038d6/bastian},
doi = {10.1128/AEM.00575-11},
interhash = {3db8757c79c2bbc557e709197512559c},
intrahash = {87adbada4c59b528370d7ee2b0a038d6},
issn = {1098-5336},
journal = {Appl. Environ. Microbiol.},
keywords = {Carbon Complex, Corynebacterium Dehydrogenase Dioxide, Escherichia Glycolysis, Isotopes, NADP Pathway, Pentose Phosphate Proteins, Pyruvate Transhydrogenases Valine, coli coli, glutamicum, myown},
language = {eng},
month = sep,
number = 18,
pages = {6644--6652},
pmcid = {PMC3187166},
pmid = {21784914},
timestamp = {2018-02-09T12:18:56.000+0100},
title = {Comparative 13C metabolic flux analysis of pyruvate dehydrogenase complex-deficient, {L}-valine-producing {Corynebacterium} glutamicum},
volume = 77,
year = 2011
}