Becker, Judith;
Klopprogge, Corinna;
Zelder, Oskar;
Heinzle, Elmar;
Wittmann, Christoph
Amplified Expression of Fructose 1,6-Bisphosphatase in Corynebacterium glutamicum Increases In Vivo Flux through the Pentose Phosphate Pathway and Lysine Production on Different Carbon Sources
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Media type:
E-Article
Title:
Amplified Expression of Fructose 1,6-Bisphosphatase in Corynebacterium glutamicum Increases In Vivo Flux through the Pentose Phosphate Pathway and Lysine Production on Different Carbon Sources
Published:
American Society for Microbiology, 2005
Published in:
Applied and Environmental Microbiology, 71 (2005) 12, Seite 8587-8596
Language:
English
DOI:
10.1128/aem.71.12.8587-8596.2005
ISSN:
0099-2240;
1098-5336
Origination:
Footnote:
Description:
ABSTRACT The overexpression of fructose 1,6-bisphosphatase (FBPase) in Corynebacterium glutamicum leads to significant improvement of lysine production on different sugars. Amplified expression of FBPase via the promoter of the gene encoding elongation factor TU (EFTU) increased the lysine yield in the feedback-deregulated lysine-producing strain C. glutamicum lysC fbr by 40% on glucose and 30% on fructose or sucrose. Additionally formation of the by-products glycerol and dihydroxyacetone was significantly reduced in the P EFTU fbp mutant. As revealed by 13 C metabolic flux analysis on glucose the overexpression of FBPase causes a redirection of carbon flux from glycolysis toward the pentose phosphate pathway (PPP) and thus leads to increased NADPH supply. Normalized to an uptake flux of glucose of 100%, the relative flux into the PPP was 56% for C. glutamicum lysC fbr P EFTU fbp and 46% for C. glutamicum lysC fb r . The flux for NADPH supply was 180% in the P EFTU fbp strain and only 146% in the parent strain. Amplification of FBPase increases the production of lysine via an increased supply of NADPH. Comparative studies with another mutant containing the sod promoter upstream of the fbp gene indicate that the expression level of FBPase relates to the extent of the metabolic effects. The overexpression of FBPase seems useful for starch- and molasses-based industrial lysine production with C. glutamicum . The redirection of flux toward the PPP should also be interesting for the production of other NADPH-demanding compounds as well as for products directly stemming from the PPP.