Verlag des Forschungszentrums Jülich
JUEL-3531
Hermann, Thomas
Untersuchungen zum Transport von Isoleucin bei Corynebacterium glutamicum
98 S., 1998
Since the discovery that Corynebacterium glutamicum is an effective producer
of glutamate, the production of amino acids has become an important
biotechnologigical process. L-isoleucine produced by C. glutamicum has a world
market of 500 t/a. Significant progress in optimizing isoleucine production
has been achieved by focusing the interests on enzyme activities and
regulation. The final step, the excretion of isoleucine into the medium, is
also relevant for production since it is an important point of control in the
overall flux.
The transmembrane isoleucine flux in C. glutamicum could be differentiated
into carrier-mediated uptake, carrier-mediated excretion, and diffusion.
Isoleucine excretion was shown to function as a secondary transport process
driven by the membrane potential and coupled to the movements of protons
presumably with a stoichiometry of 2:1 (protons:isoleucine). Furthermore it
was shown that isoleucine excretion is regulated by the cytoplasmic isoleucine
concentration on the level of expression. The isoleucine uptake system was
cloned and sequenced. In 300-l fed-batch fermentations transport processes
were measured and balanced. Finally the separation of cytoplasmic and membrane
proteins of C. glutamicum by 2-D-PAGE was established.
Neuerscheinungen
Schriften des Forschungszentrums Jülich
Ihre Ansprechperson
Heike Lexis
+49 2461 61-5367
zb-publikation@fz-juelich.de