The Role of Sugar Uptake and Channelling for Citric Acid Accumulation by Aspergillus niger
Christian P. Kubicek
Institut fur Biochemische Technologie und Mikrobiologie, Abteilung für Mikrobielle Biochemie, TU Wien, Getreidemarkt 9-172.5, A-1060 Wien, Austria
Article history:
Received December 4, 1997
Accepted June 17, 1998
Key words:
Aspergillus niger, citric add accumulation, hexokinase, glucose transport, trehalose-6-phosphate, regulation
Summary:
The final yield of citric acid in fermentations by Aspergillus niger is strongly dependent on the type and concentration of the carbon source. Here will be reviewed the current understanding of the mechanism by which the carbon source and its concentration influence citric acid accumulation, which emphasizes a major regulatory point at the level of hexose transport and phosphorylation. Evidence for regulation of the rate of citric acid accumulation and glycolysis by trehalose-6-phosphate will be presented, and a successful recombinant strategy for its relief will be shown.
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