Corynebacterium glutamicum tailored for high-yield L-valine production.
We recently engineered the wild type of Corynebacterium glutamicum for the growth-decoupled production of L: -valine from glucose by inactivation of the pyruvate dehydrogenase complex and additional overexpression of the ilvBNCE genes, encoding the L-valine biosynthetic enzymes acetohydroxyacid synthase, isomeroreductase, and transaminase B. Based on the first generation of pyruvate-dehydrogenase-complex-deficient C. glutamicum strains, a second generation of high-yield L-valine producers was constructed by successive deletion of the genes encoding pyruvate:quinone oxidoreductase, phosphoglucose isomerase, and pyruvate carboxylase and overexpression of ilvBNCE. In fed-batch fermentations at high cell densities, the newly constructed strains produced up to 410 mM (48 g/l) L-valine, showed a maximum yield of 0.75 to 0.86 mol/mol (0.49 to 0.56 g/g) of glucose in the production phase and, in contrast to the first generation strains, excreted neither pyruvate nor any other by-product tested.
Blombach
Bastian
B
Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany.
Schreiner
Mark E
ME
Bartek
Tobias
T
Oldiges
Marco
M
Eikmanns
Bernhard J
BJ
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018533:Biomass; D053898:Biosynthetic Pathways; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D015870:Gene Expression; D005818:Genetic Engineering; D050540:Ketol-Acid Reductoisomerase / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics / Q000378:metabolism; D000637:Transaminases / Q000235:genetics / Q000378:metabolism; D014633:Valine / Q000378:metabolism*
D001426:Bacterial Proteins; D011768:Pyruvate Dehydrogenase Complex; D010088:Oxidoreductases; D050540:Ketol-Acid Reductoisomerase; D000637:Transaminases; C019798:branched-chain-amino-acid transaminase; D014633:Valine