Asymmetric Whole-Cell Bio-Reductions of (R)-Carvone Using Optimized Ene Reductases
Abstract(2R,5R)-dihydrocarvone is an industrially applied building block that can be synthesized by site-selective and stereo-selective C=C bond bio-reduction of (R)-carvone. Escherichia coli (E. coli) cells overexpressing an ene reductase from Nostoc sp. PCC7120 (NostocER1) in combination with a cosubstrate regeneration system proved to be very effective biocatalysts for this reaction. However, the industrial applicability of biocatalysts is strongly linked to the catalysts’ activity. Since the cell-internal NADH concentrations are around 20-fold higher than the NADPH concentrations, we produced E. coli cells where the NADPH-preferring NostocER1 was exchanged with three different NADH-accepting NostocER1 mutants. These E. coli whole-cell biocatalysts were used in batch operated stirred-tank reactors on a 0.7 l-scale for the reduction of 300 mM (R)-carvone. 287 mM (2R,5R)-dihydrocarvone were formed within 5 h with a diasteromeric excess of 95.4% and a yield of 95.6%. Thus, the whole-cell biocatalysts were strongly improved by using NADH-accepting enzymes, resulting in an up to 2.1-fold increased initial product formation rate leading to a 1.8-fold increased space-time yield when compared to literature. View Full-Text
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Mähler, C.; Burger, C.; Kratzl, F.; Weuster-Botz, D.; Castiglione, K. Asymmetric Whole-Cell Bio-Reductions of (R)-Carvone Using Optimized Ene Reductases. Molecules 2019, 24, 2550.
Mähler C, Burger C, Kratzl F, Weuster-Botz D, Castiglione K. Asymmetric Whole-Cell Bio-Reductions of (R)-Carvone Using Optimized Ene Reductases. Molecules. 2019; 24(14):2550.Chicago/Turabian Style
Mähler, Christoph; Burger, Christian; Kratzl, Franziska; Weuster-Botz, Dirk; Castiglione, Kathrin. 2019. "Asymmetric Whole-Cell Bio-Reductions of (R)-Carvone Using Optimized Ene Reductases." Molecules 24, no. 14: 2550.
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