Ionic Liquids as Tool to Improve Enzymatic Organic Synthesis

Abstract

Ionic liquids (ILs) have now been acknowledged as reaction media for biotransformations. The first three examples were reported in this field in 2000, and since then, numerous applications have been reported for biocatalytic reactions using ILs. Two topics using ILs for enzymatic reactions have been reviewed from the standpoint of biocatalyst mediating organic synthesis; the first is "Biocatalysis in Ionic Liquids" which includes various types of biocatalytic reactions in ILs (section 2): (1) recent examples of lipase-mediated reactions using ILs as reaction media for biodiesel oil production and for sugar ester production, (2) oxidase-catalyzed reactions in ILs, (3) laccase-catalyzed reactions, (4) peroxidase-catalyzed reactions, (4) cytochrome-mediated reactions, (5) microbe-mediated hydrations, (6) protease-catalyzed reactions, (8) whole cell mediated asymmetric reduction of ketones, (10) acylase-catalyzed reactions, (11) glycosylation or cellulase-mediated hydrolysis of polysaccharides, (12) hydroxynitrile lyase-catalyzed reaction, (13) fluorinase or haloalkane dehydrogenase-catalyzed reaction, (14) luciferase-catalyzed reactions, and (15) biocatalytic promiscuity of enzymatic reactions for organic synthesis using ILs. The second is "Enzymes Activated by Ionic Liquids for Organic Synthesis", particularly describing the finding story of activation of lipases by the coating with a PEG-substituted IL (section 3). The author's opinion toward "Future Perspectives of Using ILs for Enzymatic Reactions" has also been discussed in section 4.

Effects of phosphonium‐based ionic liquids on the lipase activity evaluated by experimental results and molecular docking

“…In fact, after the first reports on IL-based reaction media for biocatalysis in 2000, [18][19][20] an enhancement in the biocatalysis research field with ILs was noticed. 21 ILs are molten salts composed of a large organic cation and an organic or inorganic anion, which by general definition should display melting temperatures below 100 C. 22 Due to their ionic nature, most ILs display singular properties such as negligible vapor pressure, low flammability, high thermal and chemical stability, and a high solvation ability for a wide range of compounds. 22,23 In addition to these characteristics, the adjustment of their physical properties can be achieved by tailoring the cation and anion chemical structures, allowing the IL design for a particular propose.…”

Non‐Conventional Media as Strategy to Overcome the Solvent Dilemma in Chemoenzymatic Tandem Catalysis

“…In particular ILs, which are salts with low melting point composed of an organic cation and an organic or inorganic anion, have been widely investigated as non‐conventional media in biocatalysis for two decades . Many reports have demonstrated the ability of ILs to stabilize different kinds of enzymes through the microenvironment generated and acting as such a liquid support . More recently, DESs have emerged as a new family of green solvents which find widespread applications in a variety of areas including biocatalysis and metal catalyzed organic reactions.…”

Benzoate Surfactants for Enhancing the Activity of Lipoprotein Lipase from Burkholderia Species in Organic Solvent

“…They include the immobilization of enzymes on solid supporters [6][7][8][9][10][11][12] and the use of additives such as inorganic salts, [13][14][15][16][17] ionic liquids, [18][19][20][21][22] or surfactants. They include the immobilization of enzymes on solid supporters [6][7][8][9][10][11][12] and the use of additives such as inorganic salts, [13][14][15][16][17] ionic liquids, [18][19][20][21][22] or surfactants.…”