Biocatalysis in Ionic Liquids

Rantwijk, Fred van; Sheldon, Roger A.

doi:10.1021/cr050946x

Cited by 1,485 publications

(896 citation statements)

References 219 publications

Supporting

Mentioning

865

Contrasting

Unclassified

Order By: Relevance

“…Many literature surveys are available to different audiences spanning disciplines from asymmetric catalysis, homogeneous catalysis, organic synthesis, green chemistry, biotransformations, analytical chemistry, industrial applications, enzymatic reactions and others. [3][4][5][6][7][8][9][10][11][12] Despite all advances on the basic properties, comprehension and use of ILs, there are still many things left to be achieved. And, somewhat surprising, their physical and chemical properties still have many issues under debate.…”

Section: Introductionmentioning

confidence: 99%

The impressive chemistry, applications and features of ionic liquids: properties, catalysis & catalysts and trends

Neto¹,

Spencer²

2012

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

Algumas das nossas contribuições para o desenvolvimento da área da catálise em líquidos iônicos são descritas. Além disto, o uso de ligantes ionofílicos bem como a utilização de catalisadores com "etiquetas iônicas" são apresentados e discutidos. Devido à importância dos líquidos iônicos, as suas propriedades fisicoquímicas de interesse bem como a sua organização supramolecular são temas discutidos.Some of our contributions to the development of catalysis in ionic liquids are described. Also, the use of ionophilic ligands and catalysts with ionic tags are presented and discussed. Due to the importance of ionic liquids, some physicochemical properties of interest and their supramolecular organization are described.

show abstract

Section: Introductionmentioning

confidence: 99%

The impressive chemistry, applications and features of ionic liquids: properties, catalysis & catalysts and trends

Neto¹,

Spencer²

2012

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…The initial interest on ILs as alternative extractive fluids results from their physical and chemical advantages, namely negligible flammability and vapour pressure, high solvation ability, high chemical stability, high selectivity, and easiness in recovering and recycling them [25][26][27][28][29]. Moreover, it was already shown that adequate ILs do not significantly inactivate enzymes ensuring thus their structural integrity and enzymatic activity [5,27].…”

Section: Introductionmentioning

confidence: 99%

Extraction of vanillin using ionic-liquid-based aqueous two-phase systems

Cláudio

Freire

et al. 2010

Separation and Purification Technology

183

View full text Add to dashboard Cite

a b s t r a c tTo explore proper extractive solvents and to design an optimized separation process it is highly imperative to understand the molecular-based phenomena governing the solutes partitioning. Moreover, the development of new techniques for the biomolecules separation and purification, while maintaining their functional characteristics unchanged, is still ongoing. Therefore, in this work, the partition coefficients of vanillin, a compound with well-known organoleptic properties, were determined using improved ionicliquid-based aqueous two-phase systems (ATPS). Three main parameters were evaluated through the vanillin partitioning process: the ionic liquid (IL) cation and anion structure, the temperature of equilibrium and the available concentration of vanillin in the global system. In all systems and conditions tested, vanillin preferentially migrates for the IL-rich phase. In addition, the three studied parameters largely influence the vanillin partitioning. In an attempt to elucidate the thermodynamics of the partitioning process, the standard molar thermodynamic functions of transfer of vanillin were also determined based on the temperature dependence data. These data indicate that the partition of vanillin results from an interplay between enthalpic and entropic contributions where both the IL anion and more complex cations play an essential role. Moreover, viscosities and densities of both aqueous phases were experimentally measured at the mass fraction compositions for which the partition coefficients were determined. The results gathered in this work indicate that IL-based ATPS can be further employed in the extraction and purification of vanillin from different matrices, as confirmed by the large partition coefficients obtained and improved low viscosity systems.

show abstract

“…31,33,34 While the hydrophobic effect that increases protein stabilization is absent in organic ionic liquids, one advantage to biocatalysis in ILs as opposed to aqueous buffers is the longer activity of enzymes in ILs, which is thought to arise from the slow breaking and remaking of hydrogen bonds in the nonaqueous medium. 35 Studies of cellulase-induced catalysis in ionic liquids are, however, still limited. 5,[36][37][38][39] The physical and chemical properties of ionic liquids vary considerably depending on their cation-anion pair.…”

Section: Introductionmentioning

confidence: 99%

Enzyme-Catalyzed Hydrolysis of Cellulose in Ionic Liquids: A Green Approach Toward the Production of Biofuels

2010

View full text Add to dashboard Cite

We investigated the reactivity and stability of a commercial mixture of cellulases in eight ionic liquids by optical and calorimetric techniques. First, hydrolysis by cellulases from Tricoderma reesei in these ionic liquids was benchmarked against that in aqueous buffer. Only 1-methylimidazolium chloride (mim Cl) and tris-(2-hydroxyethyl)methylammonium methylsulfate (HEMA) provided a medium in which hydrolysis could occur. While hydrolysis at 65 °C is initially much faster in buffer than in these two liquids, it reaches a plateau after 2 h, whereas the reaction progresses monotonically in the two ionic liquids. This difference in the rate of hydrolysis is largely attributed to two factors: (1) the higher viscosity of the ionic liquids and (2) the enzymes are irreversibly denatured at 50 °C in buffer while they are stable to temperatures as high as 115 °C in HEMA. We explored whether fluorescence quenching of aromatic amino acids of the enzymes was indeed a signature of protein denaturation, as has been suggested in the literature, and concluded that quenching is not necessarily associated with denaturation. When it does occur, for example, in the presence of ionic liquids formed from imidazolium cations and chloride anions, it arises from the imidazolium rather than the chloride. Finally, we conclude that HEMA is a promising, novel, green medium for performing cellulose hydrolysis reactions to convert biomass into biofuels. Because of the thermal stability it imparts to enzymes, its ability to solubilize biomass, and the fact that it does not quench tryptophyl fluorescence (thus permitting monitoring of the enzymes by fluorescence spectroscopy), HEMA provides an ideal starting point for the design of ionic liquids, not only for the hydrolysis of biomass, but also for use with a wide spectrum of enzymatic reactions. KeywordsAmino acids, biofuels, biomass, catalysts, cellulose, chlorine compounds, denaturation, enzymes, fluorescence, fluorescence spectroscopy, hydrolysis, ionization of liquids, organic acids, aromatic amino acid, calorimetric techniques, chloride anions, commercial mixtures Arlington, P.O. Box 19065, Arlington, Texas 76019 ReceiVed: December 21, 2009; ReVised Manuscript ReceiVed: March 16, 2010 We investigated the reactivity and stability of a commercial mixture of cellulases in eight ionic liquids by optical and calorimetric techniques. First, hydrolysis by cellulases from Tricoderma reesei in these ionic liquids was benchmarked against that in aqueous buffer. Only 1-methylimidazolium chloride (mim Cl) and tris-(2-hydroxyethyl)methylammonium methylsulfate (HEMA) provided a medium in which hydrolysis could occur. While hydrolysis at 65°C is initially much faster in buffer than in these two liquids, it reaches a plateau after 2 h, whereas the reaction progresses monotonically in the two ionic liquids. This difference in the rate of hydrolysis is largely attributed to two factors: (1) the higher viscosity of the ionic liquids and (2) the enzymes are irreversibly denatured at 50°C in b...

show abstract

Biocatalysis in Ionic Liquids

Cited by 1,485 publications

References 219 publications

The impressive chemistry, applications and features of ionic liquids: properties, catalysis & catalysts and trends

The impressive chemistry, applications and features of ionic liquids: properties, catalysis & catalysts and trends

Extraction of vanillin using ionic-liquid-based aqueous two-phase systems

Enzyme-Catalyzed Hydrolysis of Cellulose in Ionic Liquids: A Green Approach Toward the Production of Biofuels

Contact Info

Product

Resources

About