Abstract
Using the pyruvate production strain Escherichia coli YYC202 IdhA::Kan
different process alternatives are studied with the aim of preventing
potential product inhibition by appropriate product separation. This
strain is completely blocked in its ability to convert pyruvate into
acetyl-CoA or acetate, resulting in acetate auxotrophy during growth in
glucose minimal medium. Continuous experiments with cell retention,
repetitive fed-batch, and an in situ product recovery (ISPR) process
with fully integrated electrodialysis were tested. Although the
continuous approach achieved a high volumetric productivity (Q(P)) of
110 g L(-1) d(-1), this approach was not pursued because of long-term
production strain instabilities. The highest pyruvate/glucose molar
yield of up to 1.78 mol mol(-1) together with high Q(P) 145 g L(-1)
d(-1) and high pyruvate titers was achieved by the repetitive fed-batch
approach. To separate pyruvate from fermentation broth a fully
integrated continuous process was developed. In this process
electrodialysis was used as a separation unit. Under optimum conditions
a (calculated) final pyruvate titer of >900 mmol L(-1) (79 g L(-1)) was
achieved. (C) 2004 Wiley Periodicals, Inc.
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