Stimulation of Laccase Biocatalysis in Ionic Liquids: A Review on Recent Progress

Líu, Hao; Wu, Xing‐Long; Sun, Jiasen; Chen, Shicheng

doi:10.2174/1389203718666161122110647

Cited by 17 publications

(13 citation statements)

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“…For laccase, there was only indirect evidence that Tve laccase could be activated by [Mmim]MeSO 4 at elevated pHs, i.e., 7 and 9 [ 29 ]. Assumptions about pH optima shifts were proposed in our previous article [ 30 ] and confirmed in this work.…”

Section: Discussionsupporting

confidence: 80%

Molecular Mechanisms Underlying Inhibitory Binding of Alkylimidazolium Ionic Liquids to Laccase

et al. 2017

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Water-miscible alkylimidazolium ionic liquids (ILs) are “green” co-solvents for laccase catalysis, but generally inhibit enzyme activity. Here, we present novel insights into inhibition mechanisms by a combination of enzyme kinetics analysis and molecular simulation. Alkylimidazolium cations competitively bound to the TI Cu active pocket in the laccase through hydrophobic interactions. Cations with shorter alkyl chains (C2~C6) entered the channel inside the pocket, exhibiting a high compatibility with laccase (competitive inhibition constant Kic = 3.36~3.83 mM). Under the same conditions, [Omim]Cl (Kic = 2.15 mM) and [Dmim]Cl (Kic = 0.18 mM) with longer alkyl chains bound with Leu296 or Leu297 near the pocket edge and Leu429 around TI Cu, which resulted in stronger inhibition. Complexation with alkylimidazolium cations shifted the pH optima of laccase to the right by 0.5 unit, and might, thereby, lead to invalidation of the Hofmeister series of anions. EtSO4− showed higher biocompatibility than did Ac− or Cl−, probably due to its binding near the TI Cu and its hindering the entry of alkylimidazolium cations. In addition, all tested ILs accelerated the scavenging of 2, 2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, which, however, did not play a determining role in the inhibition of laccase.

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Section: Discussionsupporting

confidence: 80%

Molecular Mechanisms Underlying Inhibitory Binding of Alkylimidazolium Ionic Liquids to Laccase

et al. 2017

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“…An increase in pH may have caused a conformational change in laccase structure-especially on its catalytic site-thus inhibiting internal electron transfer and differing reaction product [19]. This suggests that enzyme encapsulation affects neither protein conformation nor enzyme function, keeping this laccase the characteristic behavior of the blue ones [19][20][21]. The inhibition of T2 Cu site An increase in pH may have caused a conformational change in laccase structure-especially on its catalytic site-thus inhibiting internal electron transfer and differing reaction product [19].…”

Section: Optimum Ph For Enzyme Activitymentioning

confidence: 99%

Nanoencapsulated Laccases Obtained by Double-Emulsion Technique. Effects on Enzyme Activity pH-Dependence and Stability

et al. 2020

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One primary drawback of enzyme catalysis at industrial scale is the short-term service life of the enzymes, they lose their activity due to oxidation or other processes which results in less stability and a shorter lifetime thereby rendering them less efficient. An effective way to increase the stability of the enzymes is to attach them to nanoparticles. In this work, the polymer Eudragit® L 100-55 sensitive to pH was used to prepare laccase polymeric nanoparticles by the double-emulsion solvent evaporation approach. The size and morphology of the nanoparticles obtained were evaluated—as well as the encapsulation efficiency and zeta potential. pH effect on activity and stability was compared between free and immobilized laccase. Their stability was also determined in a sequential assay involving acidic pHs up to alkaline ones. The nanoparticles had a spherical shape with a mean size of 147 nm, zeta potential of −22.7 mV at pH 7.0 and load efficiency of 87%. The optimum pH of both free and immobilized laccases was 3.0, being the nanoparticles more stable at acidic pHs. Thus, this would be the first report of obtaining laccase nanoparticles with potential application in animal feed due to the stability conferred to enzymatic activity at pHs similar to those present in the gastrointestinal tract of rabbits, which would allow their potential use in animal feed.

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“…Increase in pH might have caused a conformational change in laccase structure and specially on its catalytic site, thus inhibiting internal electron transfer and differing reaction product [18]. This suggests that enzyme encapsulation neither affect protein conformation nor enzyme function, keeping this laccase the characteristic behavior of the blue ones [18][19][20]. The inhibition of T2 Cu site might be explained by the presence of OHions, which prevent oxygen reduction to water via the reaction O2 − + 2H + → H2O [17].…”

Section: Nanoparticles Characterizationmentioning

confidence: 99%

Double-emulsion technique applied to laccase immobilization on polymeric nanoparticles

Chong-Cerda¹,

Levin²,

Castro‐Ríos³

et al. 2020

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One primary drawback of enzyme catalysis at industrial scale is the short term service life of the enzymes. Enzymes lose their activity due to oxidation or other processes which results in less stability and a shorter lifetime thereby rendering them less efficient. An effective way to increase the stability, longevity and reusability of the enzymes is to attach them to nanoparticles by applying the double-emulsion technique. In this work the polymer Eudragit® L 100-55 sensitive to pH was used to prepare laccase polymeric nanoparticles by the double-emulsion solvent evaporation approach. The size and morphology of the nanoparticles obtained was evaluated by Scanning Electron Microscope and particle size distribution was assessed by Photon Correlation Spectroscopy. Encapsulation efficiency and zeta potential were calculated. The effect of pH on laccase activity and stability was compared between free laccase and the immobilized one. Their stability was also determined in a sequential assay involving acidic pHs up to alkaline ones. The nanoparticles had a spherical shape with a mean size of 289 nm, zeta potential of -22.7 mV at pH 7.0, and load efficiency of 87%. The optimum pH of both free and immobilized laccases was 3.0, being the nanoparticles more stable at acidic pHs (2.0-4.0). Howevwe, this last kept 80% of enzyme activity at pH 2.0 approx., after 24 h. The polymer Eudragit® L 100-55 also conferred them resistance towards the pHs usually found at the gastrointestinal tract. These results suggest the potential use of nanoparticles as adjuvants in animal feed, serving as carriers for oral laccase delivery.

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Stimulation of Laccase Biocatalysis in Ionic Liquids: A Review on Recent Progress

Cited by 17 publications

References 0 publications

Molecular Mechanisms Underlying Inhibitory Binding of Alkylimidazolium Ionic Liquids to Laccase

Molecular Mechanisms Underlying Inhibitory Binding of Alkylimidazolium Ionic Liquids to Laccase

Nanoencapsulated Laccases Obtained by Double-Emulsion Technique. Effects on Enzyme Activity pH-Dependence and Stability

Double-emulsion technique applied to laccase immobilization on polymeric nanoparticles

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