TY - JOUR

T1 - Impact of deep eutectic solvents (DESs) and individual DES components on alcohol dehydrogenase catalysis: connecting experimental data and molecular dynamics simulations

AU - Bittner, Jan Philipp

AU - Zhang, Ningning

AU - Huang, Lei

AU - María, Pablo Domínguez de

AU - Jakobtorweihen, Sven

AU - Kara, Selin

N1 - Funding information: The authors thank the Deutsche Forschungsgemeinschaft (DFG) (grant numbers: KA 4399/3-1 and JA 2500/5-1) for the financial support. This research used computational resources provided by The North-German Supercomputing Alliance (HLRN). The authors thank Assoc. Prof. Dr Diederik Johannes Opperman (University of the Free State, South Africa) for the recombinant plasmid containing the HLADH gene. Assoc. Prof. Menglin Chen (Aarhus University, Denmark) is gratefully thanked for the use of the rheometer. Furthermore, we would also like to thank Michelle Leganger Juul Sørensen for the technical assistance.

PY - 2022

Y1 - 2022

N2 - For a knowledge-based design of enzyme catalysis in deep eutectic solvents (DESs), the influence of the DES properties (e.g., water activity and viscosity) and the impact of DESs and their individual components must be assessed. This paper investigates three different DESs: choline chloride-glycerol (ChCl-Gly), choline chloride-ethylene glycol (ChCl-EG), and ethyl ammonium chloride-glycerol (EACl-Gly). The specific activity and half-life time of horse liver alcohol dehydrogenase (HLADH) were experimentally determined in these DESs with water contents ranging from 0%-100%. HLADH showed limited activity in neat DESs, which was enhanced by adding water. Experiments with individual DES components of ChCl-Gly were carried out to clarify their individual influence. Glycerol acts as a strong stabilizer for the enzyme, whereas choline chloride's results are deleterious. To understand the experimental findings, molecular dynamics (MD) simulations were carried out to quantify the solvation layer and calculate the spatial distribution of the solvent molecules around HLADH. The experimental and the in silico approach suggests that designing novel DESs with higher glycerol loadings would result in improved media for biocatalysis. This is demonstrated by performing the reduction of cinnamaldehyde to cinnamyl alcohol-a relevant compound for the food industry and cosmetics-in ChCl-Gly (1 : 9 molar ratio), with 20 vol% water to decrease the viscosity. HLADH is highly active and stable under these new conditions, giving promising productivity (15.3 g L-1 d-1). This paper demonstrates that DESs can be designed to be both substrate-solubilizers and enzyme-compatible, opening new research lines for green chemistry and biocatalysis.

AB - For a knowledge-based design of enzyme catalysis in deep eutectic solvents (DESs), the influence of the DES properties (e.g., water activity and viscosity) and the impact of DESs and their individual components must be assessed. This paper investigates three different DESs: choline chloride-glycerol (ChCl-Gly), choline chloride-ethylene glycol (ChCl-EG), and ethyl ammonium chloride-glycerol (EACl-Gly). The specific activity and half-life time of horse liver alcohol dehydrogenase (HLADH) were experimentally determined in these DESs with water contents ranging from 0%-100%. HLADH showed limited activity in neat DESs, which was enhanced by adding water. Experiments with individual DES components of ChCl-Gly were carried out to clarify their individual influence. Glycerol acts as a strong stabilizer for the enzyme, whereas choline chloride's results are deleterious. To understand the experimental findings, molecular dynamics (MD) simulations were carried out to quantify the solvation layer and calculate the spatial distribution of the solvent molecules around HLADH. The experimental and the in silico approach suggests that designing novel DESs with higher glycerol loadings would result in improved media for biocatalysis. This is demonstrated by performing the reduction of cinnamaldehyde to cinnamyl alcohol-a relevant compound for the food industry and cosmetics-in ChCl-Gly (1 : 9 molar ratio), with 20 vol% water to decrease the viscosity. HLADH is highly active and stable under these new conditions, giving promising productivity (15.3 g L-1 d-1). This paper demonstrates that DESs can be designed to be both substrate-solubilizers and enzyme-compatible, opening new research lines for green chemistry and biocatalysis.

UR - http://www.scopus.com/inward/record.url?scp=85124533736&partnerID=8YFLogxK

U2 - 10.1039/D1GC04059F

DO - 10.1039/D1GC04059F

M3 - Article

VL - 24

SP - 1120

EP - 1131

JO - Green chemistry

JF - Green chemistry

SN - 1463-9262

IS - 3

ER -