title: Analysing overexpression of L-valine biosynthesis genes in pyruvate-dehydrogenase-deficient Corynebacterium glutamicum.
abstract: L-valine biosynthesis was analysed by comparing different plasmids in pyruvate-dehydrogenase-deficient Corynebacterium glutamicum strains in order to achieve an optimal production strain. The plasmids contained different combinations of the genes ilvBNCDE encoding for the L-valine forming pathway. It was shown that overexpression of the ilvBN genes encoding acetolactate synthase is obligatory for efficient pyruvate conversion and to prevent L-alanine as a by-product. In contrast to earlier studies, overexpression of ilvE encoding transaminase B is favourable in pyruvate-dehydrogenase-negative strains. Its amplification enhanced L-valine formation and avoided extra- and intracellular accumulation of ketoisovalerate.
authors.affiliation: Institute of Biotechnology 2, Forschungszentrum Jülich, 52425, Jülich, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Bartek
authors.forename: Enrico
authors.initials: E
authors.lastname: Zönnchen
authors.forename: Bianca
authors.initials: B
authors.lastname: Klein
authors.forename: Robert
authors.initials: R
authors.lastname: Gerstmeir
authors.forename: Pia
authors.initials: P
authors.lastname: Makus
authors.forename: Siegmund
authors.initials: S
authors.lastname: Lang
authors.forename: Marco
authors.initials: M
authors.lastname: Oldiges
mesh_terms: D000409:Alanine / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics*; D053898:Biosynthetic Pathways; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D018628:Gene Dosage; D015870:Gene Expression; D005810:Multigene Family; D010957:Plasmids; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics*; D014633:Valine / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D011768:Pyruvate Dehydrogenase Complex; D014633:Valine; D000409:Alanine