Application of immobilized cells ofThermoanaerobium brockii for stereoselective reductions of oxo-acid esters |
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Authors: | B Sonnleitner A Fiechter |
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Institution: | 1. Department of Biotechnology, Swiss Federal Institute of Technology, CH-8093, Zürich-H?nggerberg, Switzerland
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Abstract: | Summary Cells ofThermoanaerobium brockii were immobilized by entrapment methods as easy-to-handle biocatalyst for stereoselective reductions of oxo-acid esters. Different
matrix materials were tested: agarose, k-carrageenan, alginate, polyacrylamide and polyurethanes. The two latter matrices
allowed useful lifetimes of the immobilized biocatalysts of more than 2 months at thermophilic operation temperatures (around
65°C). Permeabilization of cells did not improve the catalytic activity. Immobilization of the cells did not enhance the thermostability.
Only after a considerable period of operation could the immobilized biocatalysts be fed with medium lacking the complex substrates
yeast extract and tryptone. Compared with freely suspended cells, reaction rates were lower.
The immobilized system proved to be a relatively stable easy-to-handle biocatalyst, however, the freely suspended cells were
superior with respect to flexibility of application and reaction velocity. |
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