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B6db references: 96250132

type Journal Article
authors Sahm, H.; Eggeling, L.; Eikmanns, B.; Kramer, R.
title Construction of L-lysine-, L-threonine-, and L-isoleucine-overproducing strains of Corynebacterium glutamicum
journal Ann N Y Acad Sci
ui 96250132
year (1996)
volume 782
pages 25-39.
keywords Biotechnology/methods
abstract The gram-negative bacterium Corynebacterium glutamicum is used for the industrial production of amino acids, for example, of L-glutamate and L- lysine. By cloning and expressing the various genes of the L-lysine pathway in C. glutamicum, we would demonstrate that an increase of the flux of L-aspartate semialdehyde to L-lysine could be obtained in strains with increased dihydrodipicolinate synthase activity. Recently we detected that in C. glutamicum two pathways exist for synthesis of D,L-diaminopimelate and L-lysine. Mutants defective in one pathway are still able to synthesize enough L-lysine for growth, but the L-lysine secretion is reduced to 50 to 70%. Using NMR spectroscopy, we could calculate how much of the L-lysine secreted into the medium is synthesized via either one or the other pathway. Amplification of the feedback inhibition insensitive homoserine dehydrogenase and homoserine kinase in a high L-lysine-overproducing strain enabled channeling of the carbon flow from the intermediate aspartate semialdehyde towards homoserine, resulting in a high accumulation of L-threonine. For a further flux from L-threonine to L-isoleucine, the allosteric control of threonine dehydratase was eliminated.
last changed 2008/04/01 16:02

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