Asymmetric whole-cell bio-reductions of (R)-carvone using optimized ene reductases

Mähler C, Burger C, Kratzl F, Weuster-Botz D, Castiglione K (2019)


Publication Type: Journal article

Publication year: 2019

Journal

Book Volume: 24

Article Number: 2550

Journal Issue: 14

DOI: 10.3390/molecules24142550

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.

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APA:

Mähler, C., Burger, C., Kratzl, F., Weuster-Botz, D., & Castiglione, K. (2019). Asymmetric whole-cell bio-reductions of (R)-carvone using optimized ene reductases. Molecules, 24(14). https://dx.doi.org/10.3390/molecules24142550

MLA:

Mähler, Christoph, et al. "Asymmetric whole-cell bio-reductions of (R)-carvone using optimized ene reductases." Molecules 24.14 (2019).

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