Design and evaluation of novel bio‐based deep eutectic solvents for highly efficient bioproduction of chiral aryl alcohol

Abstract

BACKGROUND Deep eutectic solvents (DESs) derived from bio‐available materials are promising eco‐friendly solvents in the field of biocatalysis. However, the type of bio‐based DES is still limited and its application in bioprocess has not been well‐explored. We adopted a design strategy via the combination of choline and amino acids to synthesize novel bio‐based DESs, aimed to enhance biocatalytic efficacy by exploiting the developed DESs as co‐solvents. RESULTS Various bio‐based DESs were synthesized, where the two components are both bio‐available (choline and amino acids). Their performances in the bioreduction of 2‐chloro‐1‐(3,4‐difluorophenyl)ethanone (CFPO) were subsequently evaluated with recombinant Escherichia coli cells. The efficient asymmetric production of (S)‐2‐chloro‐1‐(3,4‐difluorophenyl)ethanol ((S)‐CFPL) was successfully achieved in a developed choline acetate/lysine (ChAc/Lys)‐containing medium. ChAc/Lys can strengthen coenzyme regeneration and properly improve cell membrane permeability during bioreduction, which account for high conversion. After optimized reaction parameters were conducted in the ChAc/Lys‐buffer system, 87.0% (S)‐CFPL yield was observed with > 99.9% enantiomeric excess (ee) value at 1 mol L−1 CFPO content. The substrate loading in the established ChAc/Lys‐buffer system was increased by 3.3‐fold compared to aqueous medium. This bioprocess was also proved to be feasible at 500 mL preparative‐scale with a satisfactory conversion. CONCLUSION ChAc/Lys bio‐DES is a promising and biocompatible co‐solvent. Introducing ChAc/Lys to the reaction system is an effective strategy for challenging high substrate loading for bioreduction. Our results give a valuable insight for developing green and benign sustainable bio‐DESs for biotransformation. © 2020 Society of Chemical Industry

Advances in deep eutectic solvents and water: applications in metal- and biocatalyzed processes, in the synthesis of APIs, and other biologically active compounds

“…121 Various NADESs have also been screened in the bioreduction of 2-chloro-1-(3,4-difluorophenyl)ethanone ( 63) to (S)-2chloro-1-(3,4-difluorophenyl)ethanol (64), which is a key chiral synthon for the synthesis of P2Y12 receptor antagonist Ticagrelor (Brilinta ® ), by the recombinant E. coli BL21 (DE3), expressing a carbonyl reductase from Leifsonia xyli HS0904. 122 Mixtures of ChCl salts and amino acids [e.g., ChCl/glycine (Gly), ChCl/glutathione (GSH), ChCl/Glc, ChCl/alanine (Ala), choline acetate (ChAc)/GSH, ChAc/glutamic acid (Glu)] were found to affect strongly the pH of the medium when amounts up to 1% w/v were added to cells suspension with respect to buffer solution, in many cases with a decreased reaction yield, probably due to a change of the binding of carbonyl reductase to the substrate. Conversely, E. coli BL21 (DE3) efficiently allowed the asymmetric production (also on a preparative scale) of (S)-64 after incubating cells in a reaction medium containing ChAc/Lys, the substrate loading being 3.3-fold higher than in a pure aqueous mixture.…”

In Competition for Water: Hydrated Choline Chloride:Urea vs Choline Acetate:Urea Deep Eutectic Solvents

“…However, comparing the two series, ChCl-based DESs were found to be more deleterious than ChOAc-based ones, giving hence a boost to the design and application of OAc-based DESs. Unlike the parent ChCl-based DESs, a few mixtures of ChOAc and a HBD have been characterized, , and suggested as media for organic synthesis, enzymatic reactions, − or biomass treatment …”

Efficient Biocatalytic Synthesis of (R)-2-Chloro-1-(3,4-difluorophenyl)ethanol by the Short-Chain Dehydrogenase PpKR8 from Paraburkholderia phymatum STM815

“…S749 (GenBank: BAD99642.1), 17 Rhky-AD H f r om Rh odo coccu s k yo to nensi s ( G e n B a n k : WP_089252776.1), 18 and LxADH from Leifsonia xyli HS0904 (GenBank: AGW01025.1). 19 Similar to other shortchain dehydrogenases, PpKR8 possesses a conserved cofactorbinding site (TGXXXGXG) at the N-terminus and a conserved catalytic triad (S139-Y152-K156) (Figure S1). Moreover, the amino acid sequence of PpKR8 had only 31− 34% identity compared to the sequences of the enzymes that could catalyze 24a to produce (S)-CFPL, thus indicating that PpKR8 exhibits a different catalytic performance for catalyzing the same substrate (24a) to produce 24b.…”