Supply of Coenzymes in Saccharomyces cerevisiae for Whole-Cell Biocatalysis
Andreas Knepper, doctoral thesis Technische Universität München, 2007
Asymmetric biosyntheses allow for the production of several fine chemicals. The advantage of whole cells as biocatalysts in such processes is that they already contain the coenzymes NAD(H) or NADP(H) needed. However, the intracellular coenzyme concentration during whole-cell biocatalysis is frequently observed to be too low leading to low half-live times of the biocatalyst. Therefore, the scope of this work was to develop strategies for the production of coenzyme-enriched whole-cell biocatalysts on the example of a recombinant Saccharomyces cerevisiae yeast. By means of reaction engineering studies a suitable feeding protocol of precursors for coenzyme biosynthesis was established for the production of yeasts in fed-batch cultivations leading to an increase in the intracellular concentrations of NAD(H) and NADP(H) by a factor of 10, and 4, respectively.