Programming cascade reactions interfacing biocatalysis with transition-metal catalysis in Deep Eutectic Solvents as biorenewable reaction media

Abstract

Transition-metal complexes and purified ketoreductases work together in eutectic mixtures for the synthesis of enantiopure secondary alcohols.

Modeling Alcohol Dehydrogenase Catalysis in Deep Eutectic Solvent/Water Mixtures

“…The half‐life of HLADH in a purely aqueous system (533 min, ≈9 h) is approximately three orders of magnitude longer than those in glyceline with 0 to 12.5 % ( v / v ) H 2 O (between 4 and 7 min). In general, glyceline had a detrimental effect on the thermal stability of HLADH, which was consistent with the observation reported in the case of a purified KRED in mixtures of glyceline/water . However, many choline‐based DESs were found to stabilize heme‐dependent enzymes, such as horseradish peroxidase and cytochrome c peroxidase .…”

“…To date, in the field of redox biocatalysis, DESs have been explored by using whole cells and isolated ketoreductases (KREDs) and alcohol dehydrogenases (ADHs), as well as in bio‐oxidations mediated by ADHs, heme‐dependent enzymes, laccases, or catalases . Due to the good biocompatibility of DESs and their promotion of increased cell permeability, redox reactions catalyzed by whole cells show higher conversion and stability .…”

“…Moreover, DESs display beneficial effects, or even stereoinversion, on the enantioselectivity of bioreduction catalyzed by baker's yeast cells . Some isolated enzymes (mainly ADHs) also show good performance and the ability to be combined with metal catalysts in DESs . However, a rational evaluation of the effect of DESs, as non‐conventional media, on the behavior of oxidoreductases is still missing.…”

“…A eutectic mixture of ChCl and glycerol (Gly) (1:2 mol mol −1 ), which is also known as glyceline, was selected as a prototypical DES for ADH‐catalyzed reactions. Glyceline is one of the most successfully applied DESs for biocatalysis . MD simulations focus on the quantitative analysis of protein flexibility and hydration level, whereby the results from enzymatic activity and stability are correlated and explained.…”

The Future of Polar Organometallic Chemistry Written in Bio‐Based Solvents and Water

“…Remarkably, this tandem protocol can also successfully be performed using pure water as the reaction medium . The first cascade reactions interfacing biocatalysis with transition‐metal catalysis in DESs have also been recently published by the same authors …”