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Updated: Jun 17, 2026

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Published on: June 24, 2019
Analysing overexpression of L-valine biosynthesis genes in pyruvate-dehydrogenase-deficient Corynebacterium
Tobias Bartek1, Enrico Zönnchen, Bianca Klein
1Institute of Biotechnology 2, Forschungszentrum Jülich, 52425, Jülich, Germany.
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.
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