Importance of Phosphoenolpyruvate Carboxylase of Corynebacterium glutamicum during the Temperature Triggered Glutamic Acid Fermentation
1999; Elsevier BV; Volume: 1; Issue: 4 Linguagem: Inglês
10.1006/mben.1999.0131
ISSN1096-7184
AutoresStéphane Delaunay, Davin Uy, Marie- France Baucher, Jean‐Marc Engasser, Armel Guyonvarch, J.L. Goergen,
Tópico(s)Amino Acid Enzymes and Metabolism
ResumoTo give clues about the respective importance of phosphoenolpyruvate carboxylase (PEPc) and pyruvate carboxylase (Pc) in Corynebacterium glutamicum metabolism during a temperature triggered glutamic acid fermentation, PEPc activity was genetically amplified and Pc activity was suppressed by biotin limitation in the culture medium. In absence of Pc activity, glutamate production was dramatically reduced whereas lactate excretion was strongly increased. Whereas PEPc amplification in excess of biotin (4 mg/L) only slightly modified the cell kinetics, under biotin limiting conditions this amplification strongly improved the glutamate production (4 μg/L). When Pc was absent, PEPc activity was sufficient to allow up to 70% of the maximal glutamate production rate and seemed to have an important anaplerotic role, especially at the beginning of the production phase. In contrast, Pc was predominant during the remainder of the glutamate fermentation.
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