Production of L-lysine on different silage juices using genetically engineered Corynebacterium glutamicum.
Corynebacterium glutamicum, the best established industrial producer organism for lysine was genetically modified to allow the production of lysine on grass and corn silages. The resulting strain C. glutamicum lysC(fbr)dld(Psod)pyc(Psod)malE(Psod)fbp(Psod)gapX(Psod) was based on earlier work (Neuner and Heinzle, 2011). That mutant carries a point mutation in the aspartokinase (lysC) regulatory subunit gene as well as overexpression of D-lactate dehydrogenase (dld), pyruvate carboxylase (pyc) and malic enzyme (malE) using the strong Psod promoter. Here, we additionally overexpressed fructose 1,6-bisphosphatase (fbp) and glyceraldehyde 3-phosphate dehydrogenase (gapX) using the same promoter. The resulting strain grew readily on grass and corn silages with a specific growth rate of 0.35 h⁻¹ and lysine carbon yields of approximately 90 C-mmol (C-mol)⁻¹. Lysine yields were hardly affected by oxygen limitation whereas linear growth was observed under oxygen limiting conditions. Overall, this strain seems very robust with respect to the composition of silage utilizing all quantified low molecular weight substrates, e.g. lactate, glucose, fructose, maltose, quinate, fumarate, glutamate, leucine, isoleucine and alanine.
Biochemical Engineering Institute, Saarland University, Campus A1.5, D-66123 Saarbrücken, Germany.
Andreas
A
Neuner
Ines
I
Wagner
Tim
T
Sieker
Roland
R
Ulber
Konstantin
K
Schneider
Susanne
S
Peifer
Elmar
E
Heinzle
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D061249:Batch Cell Culture Techniques; D019149:Bioreactors / Q000382:microbiology*; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D005285:Fermentation / Q000502:physiology; D005635:Fructosediphosphates / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering / Q000379:methods*; D024601:Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+) / Q000235:genetics / Q000378:metabolism; D008239:Lysine / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D010100:Oxygen / Q000378:metabolism; D015203:Reproducibility of Results; D012820:Silage
D001426:Bacterial Proteins; D005635:Fructosediphosphates; D024601:Glyceraldehyde 3-Phosphate Dehydrogenase (NADP+); D008239:Lysine; C029063:fructose-1,6-diphosphate; D010100:Oxygen