Laccase-Catalyzed Reactions in Ionic Liquids for Green Sustainable Chemistry

Abstract

Biocatalysis is an important and enabling tool in organic synthesis, degradation of chemical compounds, and biosensors. Laccases are copper ions containing oxidase and catalyze the conversion of polyphenol or amine derivatives using molecular oxygen. Recently, significant interests have gained attention for the development of a biochemical degradation method of lignocellulosic materials from the standpoint of green sustainable chemistry. Since these compounds are highly oxidized compounds, it is difficult to convert them stereo-or chemo-selectively to high-value small molecules. Chemical oxidations generally require hazardous reagents and harsh reaction conditions; hence, the resulting produced compounds are generally low-value molecules or complicated mixtures. On the contrary, laccases allow hazardous-reagent-free highly selective oxidative chemical conversions. The reactivity of the enzymes is influenced by a set of reaction conditions, in particular, the solvent system. Ionic liquids (ILs) have now been acknowledged as useful reaction media for biotransformations. Laccase-mediated reactions in ILs have been reviewed and focused on four topics: the first is "laccase-catalyzed reactions in ILs". The second is "biosensor system using laccase-mediated reaction in ILs". The third is "improved stability of laccase by immobilization or IL type additives", and the last chapter is "improved activity of laccase in ILs by protein engineering". Our opinion toward future perspectives of laccase-mediated reactions has also been discussed in "conclusions and future perspectives".

Enzymatic Polymerization of Dihydroquercetin (Taxifolin) in Betaine-Based Deep Eutectic Solvent and Product Characterization

“…Of special interest is the use of laccase as a redox catalyst for fine organic synthesis [23][24][25][26]. Laccases (p-diphenol: oxygen oxidoreductase, EC 1.10.3.2) belong to copper-containing oxidases; they catalyze the single-electron oxidation of organic and inorganic compounds with the concomitant reduction of dioxygen to water [27,28].…”

Novel and Reusable Mesoporous Silica Supported 4-Methylbenzenesul- fonate-functionalized Ionic Liquids for Room Temperature Highly Efficient Preparation of 2,4,5-Triaryl-1H-imidazoles

“…The absorption bands appeared about 3500-3375 cm -1 and 1651 cm -1 were related to the H-O stretching and bending vibration. The characteristic absorption bands at around 1634 cm -1 , 1527 cm -1 were attributed as N=N, and C-N stretching vibrations of imidazole ring [21][22][23][24]. The bands observed at around 2867 cm -1 , 1295 cm -1 , and 738 cm-1 were ascribed to the CH 2 stretching vibration.…”

“…Ionic liquids (ILs), as a charming functional material, have found numerous applications in various areas of reaction solvents and catalysis due to their negligible vapour pressure, thermal and chemical stability, non-flammable, nonvolatile, low toxicity and strong structural design prospects [21][22][23][24][25]. Through the functional design of anions and cations of ionic liquids, the use of ILs as catalysts in the efficient synthesis of 2,4,5-triaryl-1H-imidazoles have been devoleped [26,27].…”

Effects of Ionic Liquids on Laccase from Trametes versicolor

“…The biocompatibility of ILs with proteins is important for developing the scope of applications for a given ionic liquid; that is, ionic liquids which are toxic to cells or destabilize/damage critical proteins cannot be considered for in vivo uses. Alternatively, beneficial chemical properties of ILs may be useful in many industrial bioprocesses in which enzymes are used as biocatalysts for production or conversion applications [5][6][7][8][9][10]. Specifically, the conductivity of ILs makes them ideal candidates for processes involving redox reactions while the low vapor pressure and thermal stability allow for improved recycling of these agents between processes [9,[11][12][13].…”

“…Alternatively, beneficial chemical properties of ILs may be useful in many industrial bioprocesses in which enzymes are used as biocatalysts for production or conversion applications [5][6][7][8][9][10]. Specifically, the conductivity of ILs makes them ideal candidates for processes involving redox reactions while the low vapor pressure and thermal stability allow for improved recycling of these agents between processes [9,[11][12][13].…”