Ionic liquid salt-induced inactivation and unfolding of cellulase from Trichoderma reesei

Turner, Megan B.; Spear, Scott K.; Huddleston, Jonathan G.; Holbrey, John D.; Rogers, Robin D.

doi:10.1039/b302570e

Cited by 366 publications

(301 citation statements)

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“…23 The IL [C 4 mim]Cl has been shown to have a significant denaturing effect on some enzymes, even in aqueous solution, due in part to the intrinsically high Cl -ion concentration and activity in the reaction media. 24 Interactions between Clions and charged amino acid residues on the exterior of some proteins can threaten the integrity of the secondary structure and, thus, the activity of the enzyme. Further, proper hydration, leading to the structural stability, of the enzyme is necessary in most cases to achieve activity comparable to that observed in aqueous systems.…”

Section: Resultsmentioning

confidence: 99%

Production of Bioactive Cellulose Films Reconstituted from Ionic Liquids

et al. 2004

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A new method for introducing enzymes into cellulosic matrixes which can be formed into membranes, films, or beads has been developed using a cellulose-in-ionic-liquid dissolution and regeneration process. Initial results on the formation of thin cellulose films incorporating dispersed laccase indicate that active enzyme-encapsulated films can be prepared using this methodology and that precoating the enzyme with a second, hydrophobic ionic liquid prior to dispersion in the cellulose/ionic liquid solution can provide an increase in enzyme activity relative to that of untreated films, presumably by providing a stabilizing microenvironment for the enzyme.

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Section: Resultsmentioning

confidence: 99%

Production of Bioactive Cellulose Films Reconstituted from Ionic Liquids

et al. 2004

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“…Our finding of good cellulase compatibility in modest concentration (20%, v/v) of phosphate-based ILs is in contrast to the strong deactivation or inhibition of cellulase (Turner et al 2003;Zhao et al 2007Zhao et al , 2008Docherty and Kulpa 2005 Compared with other phosphate-based ILs and chloridebased ILs investigated, [Mmim]DMP was chosen as a green solvent to pretreat corn cob in view of its biocompatibility with both lignocellulose pretreatment and cellulase activity. Both the [Mmim]DMP involved pretreatment/ saccharification process and in situ saccharification process could efficiently convert corn cob to sugars which is important from the practical viewpoint.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the biocompatibile ionic liquid 1-methyl-3-methylimidazolium dimethylphosphite pretreatment of corn cob for improved saccharification

Jiang

et al. 2010

Appl Microbiol Biotechnol

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Ionic liquid (IL) pretreatment of lignocellulose materials is a promising process in biomass conversion to renewable biofuel. More in-depth research involving environment-friendly IL is much needed to explore pretreatment green route. In our case, IL 1-methyl-3-methylimidazolium dimethylphosphite ([Mmim]DMP) was chosen as an environment-friendly solvent to pretreat corn cob in view of its biocompatibility with both lignocellulose solubility and cellulase activity. The pretreatment/saccharification process and in situ saccharification process involving [Mmim]DMP were efficiently performed in bioconversion of corn cob to sugars, and more than 70% saccharification rates were obtained. Furthermore, the fermentability of reducing sugars obtained from the hydrolyzates was evaluated using Rhodococcus opacus strain ACCC41043 (R. opacus). High lipid production 41-43% of cell dry matter was obtained after 30 h of cultivation. GC/ MS analysis indicated that lipids from R. opacus contained mainly long-chain fatty acids with four major constituent/ oleic acid, stearic acid, palmitic acid, palmitoleic acid which are good candidates for biodiesel. These elucidated that corn cob pretreated by IL [Mmim]DMP did not bring negative effects on saccharification, cell growth, and accumulation of lipid of R. opacus. In conclusion, the IL [Mmim]DMP shows promise as green pretreatment solvent for cellulosic materials.

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“…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. Several attempts have been made to explore the activity of enzymes in ionic liquids, and there are various issues concerning the stability of these biomacromolecules in ionic liquids.…”

Section: Introductionmentioning

confidence: 99%

“…Viscosity increases with the length of the alkyl chain. Although the highly viscous bmim Cl (Table 1) slows down the rate of cellulase induced hydrolysis of cellulose, 36 it can dissolve a substantial amount of cellulose. 9 As opposed to bmim Cl, cellulose has very limited solubility in bmim PF 6 and bmim BF 4 , whereas the latter keeps the enzyme active.…”

Section: Introductionmentioning

confidence: 99%

“…36 They reported that the enzymatic activity ceases within an hour of reaction due the presence of a high concentration of chloride ions in the bmim Cl, whereas the activity is retained in bmim BF 4 . Enzymatic activity was monitored as a function of time with cellulose azure (an azo-dye tagged to the cellulose chain), 42 which upon hydrolysis releases the dye, whose absorbance is measured as a signature of the progress of reaction.…”

Section: Introductionmentioning

confidence: 99%

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

2010

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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...

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Ionic liquid salt-induced inactivation and unfolding of cellulase from Trichoderma reesei

Cited by 366 publications

References 19 publications

Production of Bioactive Cellulose Films Reconstituted from Ionic Liquids

Production of Bioactive Cellulose Films Reconstituted from Ionic Liquids

Evaluation of the biocompatibile ionic liquid 1-methyl-3-methylimidazolium dimethylphosphite pretreatment of corn cob for improved saccharification

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

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