Lipase dissolution and stabilization in ether-functionalized ionic liquids
- 4 June 2009
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Green Chemistry
- Vol. 11 (8), 1128-1138
- https://doi.org/10.1039/b905388c
Abstract
Ionic liquids (ILs) with various structures and properties have been extensively investigated in many biocatalytic reactions and processes. However, although hydrophobic ILs tend to stabilize the insoluble (suspended) enzymes, they usually have low hydrogen-bonding basicity with solutes, which limits the solubility of many substrates (such as D-glucose, ascorbic acid, and cellulose). In contrast, hydrophilic ILs (such as those based on chloride, acetate and dicyanamide) are able to dissolve many of these substances that are not quite soluble in common organic solvents. Unfortunately, enzymes are not always active in these hydrophilic media due to strong interactions (such as H-bonding) between proteins and ILs. To resolve this dilemma, we recently synthesized new acetate-based ILs carrying a long alkyloxyalkyl chain in their cations, and found that these ether-functionalized solvents are lipase-compatible and can dissolve considerable amounts of D-glucose and cellulose (Green Chem., 2008, 10, 696). In this study, we further observed that these ILs could dissolve high concentrations of lipase B from Candida antarctica (CALB) (> 5 mg/mL at 50 °C), as well as other substrates including amino acids and betulinic acid. Therefore, these novel media offer new opportunities for carrying out homogeneous enzymatic reactions, which is practically important for large substrate molecules. In this article, we further confirmed the lipase compatibility of these ILs through the transesterification between ethyl butyrate and 1-butanol. The second derivative infrared spectra of CALB suggest the conservation of secondary structures of proteins in these ILs. We further investigated these ether-functionalized ILs in two important biocatalytic reactions: enzymatic synthesis of methyl-phthalate of betulinic acid, and CALB-catalyzed synthesis of D-glucose fatty acid esters. These substrates are not very soluble in conventional organic solvents, but very soluble in ILs, which improved the catalytic efficiency of these reactions. Moderate to high conversions were achieved in both reactions.This publication has 87 references indexed in Scilit:
- Ionic liquids for aqueous two‐phase extraction and stabilization of enzymesBiotechnology & Bioengineering, 2007
- Lipase‐catalyzed synthesis of fatty acid sugar ester using extremely supersaturated sugar solution in ionic liquidsBiotechnology & Bioengineering, 2007
- Structures of ionic liquids dictate the conversion and selectivity of enzymatic glycerolysis: Theoretical characterization by COSMO‐RSBiotechnology & Bioengineering, 2007
- Fluorescence and CD spectroscopic analysis of the α‐chymotrypsin stabilization by the ionic liquid, 1‐ethyl‐3‐methylimidazolium bis[(trifluoromethyl)sulfonyl]amideBiotechnology & Bioengineering, 2004
- On the Noninnocent Nature of 1,3‐Dialkylimidazolium Ionic LiquidsAngewandte Chemie, 2004
- Preparation and Characterization of New Room Temperature Ionic LiquidsChemistry – A European Journal, 2002
- Influence of glucose solubility and dissolution rate on the kinetics of lipase catalyzed synthesis of glucose laurate in 2‐methyl 2‐butanolBiotechnology & Bioengineering, 2002
- Sol-gel immobilization of serine proteases for application in organic solventsBiotechnology & Bioengineering, 2001
- Mechanism of extraction of chymotrypsin into isooctane at very low concentrations of aerosol OT in the absence of reversed micellesBiotechnology & Bioengineering, 1994
- The Composition and Conformation of Sugars in SolutionAngewandte Chemie, 1969