TY  - JOUR
AU  - Bartek, T.
AU  - Blombach, B.
AU  - Lang, S.
AU  - Eikmanns, B.J.
AU  - Wiechert, W.
AU  - Oldiges, M.
AU  - Nöh, K.
AU  - Noack, S.
TI  - Comparative 13C-metabolic flux analysis of pyruvate dehydrogenase complex-deficient L-valine-producing Corynebacterium glutamicum
JO  - Applied and environmental microbiology
VL  - 77
SN  - 0099-2240
CY  - Washington, DC [u.a.]
PB  - Soc.
M1  - PreJuSER-15863
SP  - 6644 - 6652
PY  - 2011
N1  - 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.
AB  - 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.
KW  - Carbon Dioxide: metabolism
KW  - Carbon Isotopes: metabolism
KW  - Corynebacterium glutamicum: genetics
KW  - Corynebacterium glutamicum: metabolism
KW  - Escherichia coli: enzymology
KW  - Escherichia coli: genetics
KW  - Escherichia coli Proteins: genetics
KW  - Escherichia coli Proteins: metabolism
KW  - Glycolysis
KW  - NADP Transhydrogenases: genetics
KW  - NADP Transhydrogenases: metabolism
KW  - Pentose Phosphate Pathway
KW  - Pyruvate Dehydrogenase Complex: genetics
KW  - Valine: metabolism
KW  - Carbon Isotopes (NLM Chemicals)
KW  - Escherichia coli Proteins (NLM Chemicals)
KW  - Pyruvate Dehydrogenase Complex (NLM Chemicals)
KW  - Carbon Dioxide (NLM Chemicals)
KW  - Valine (NLM Chemicals)
KW  - NADP Transhydrogenases (NLM Chemicals)
KW  - pntA protein, E coli (NLM Chemicals)
KW  - pntB protein, E coli (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:21784914
C2  - pmc:PMC3187166
UR  - <Go to ISI:>//WOS:000294691400040
DO  - DOI:10.1128/AEM.00575-11
UR  - https://juser.fz-juelich.de/record/15863
ER  -