title: Effect of pyruvate dehydrogenase complex deficiency on L-lysine production with Corynebacterium glutamicum.
abstract: Intracellular precursor supply is a critical factor for amino acid productivity of Corynebacterium glutamicum. To test for the effect of improved pyruvate availability on L-lysine production, we deleted the aceE gene encoding the E1p enzyme of the pyruvate dehydrogenase complex (PDHC) in the L-lysine-producer C. glutamicum DM1729 and characterised the resulting strain DM1729-BB1 for growth and L-lysine production. Compared to the host strain, C. glutamicum DM1729-BB1 showed no PDHC activity, was acetate auxotrophic and, after complete consumption of the available carbon sources glucose and acetate, showed a more than 50% lower substrate-specific biomass yield (0.14 vs 0.33 mol C/mol C), an about fourfold higher biomass-specific L-lysine yield (5.27 vs 1.23 mmol/g cell dry weight) and a more than 40% higher substrate-specific L-lysine yield (0.13 vs 0.09 mol C/mol C). Overexpression of the pyruvate carboxylase or diaminopimelate dehydrogenase genes in C. glutamicum DM1729-BB1 resulted in a further increase in the biomass-specific L-lysine yield by 6 and 56%, respectively. In addition to L-lysine, significant amounts of pyruvate, L-alanine and L-valine were produced by C. glutamicum DM1729-BB1 and its derivatives, suggesting a surplus of precursor availability and a further potential to improve L-lysine production by engineering the L-lysine biosynthetic pathway.
authors.affiliation: Institute of Microbiology and Biotechnology, University of Ulm, 89069, Ulm, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Blombach
authors.forename: Mark E
authors.initials: ME
authors.lastname: Schreiner
authors.forename: Matthias
authors.initials: M
authors.lastname: Moch
authors.forename: Marco
authors.initials: M
authors.lastname: Oldiges
authors.forename: Bernhard J
authors.initials: BJ
authors.lastname: Eikmanns
mesh_terms: D001483:Base Sequence; D001709:Biotechnology; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D005285:Fermentation; D017353:Gene Deletion; D015870:Gene Expression; D005798:Genes, Bacterial; D007700:Kinetics; D008239:Lysine / Q000096:biosynthesis*; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D011768:Pyruvate Dehydrogenase Complex; D008239:Lysine