Long-term preservation of α-amylase activity in highly concentrated aqueous solutions of imidazolium ionic liquid

2018 ◽  
Vol 7 (2) ◽  
pp. 106-113 ◽  
Author(s):  
Konstantza Tonova
Keyword(s):  
Ionic Liquid ◽  
Aqueous Solutions ◽  
Free Water ◽  
Potassium Acetate ◽  
Acetate Anion ◽  
High Concentration ◽  
Imidazolium Ionic Liquid ◽  
Imidazolium Cation ◽  
Long Term Preservation

AbstractThe activity of the α-amylase enzyme incubated in aqueous solutions with a high concentration (80.2% w/v) of imidazolium ionic liquid, [C4C1im]Br, has been studied. Contrary to the complete deactivation hitherto reported in the literature, a way is found to preserve the enzyme, by adding the appropriate salt, so that the activity is saved for a long grace period. Different salts are studied and the concentration is optimized in view of the enzyme hydration. Due to the limited amount of free water available to the enzyme at higher salt concentrations, the activity decreases. The best results are obtained by adding potassium acetate, 0.200 mol dm−3. Some 90% of the activity is saved in a 2-week incubation, and a half activity remains in a month. Precipitates are observed in the samples of the solution without salt. No precipitation is noticed when acetate is present. Regardless of the fluorescence quenching, the activity is saved. The effect of the acetate on the α-amylase preservation is probably related to the ability of the acetate anion to interact with the imidazolium cation thus shielding the enzyme from being salted out and precipitated. Compared with potassium bromide, which does not interact with [C4C1im]Br, precipitation and fast inactivation are observed.

scholarly journals Time-Resolved Characterization of Dynamic Tribochemical Processes for Dicationic Imidazolium Ionic Liquid

2017 ◽  
Author(s):  
Roman Nevshupa ◽  
Marcello Conte ◽  
Silvia Guerra ◽  
Elisa Roman
Keyword(s):  
Ionic Liquid ◽  
Imidazolium Ionic Liquid ◽  
Imidazolium Cation ◽  
Water Desorption ◽  
Time Resolved ◽  
Head Groups ◽  
Volatile Products ◽  
Tribochemical Processes ◽  
Dicationic Ionic Liquid ◽  
Poly Ethylene

Dynamic tribochemical processes for dicationic ionic liquid containing a germinal imidazolium cation head groups bridged by a poly(ethylene glycol) and bis(trifluoromethylsulfonyl)imide anion were studied using time-resolved Mechanically Stimulated Gas Emission Mass-Spectrometry (MSGE-MS). In comparison with similar monocationic imidazolium ionic liquids with short alkylic or long polyether side chains the dicationic ionic liquid had lower coefficient of friction on Ti6Al4V alloy and smoother behaviour. The analysis of volatile decomposition products suggested multiple tribochemical reactions in which both anionic and cationic moieties are involved. Tribochemical degradation of cations was mainly through detachment of the side and bridging chains from the imidazolium head groups. Absence of volatile products containing nitrogen implies that imidazole group remained unchanged. Hydrogen and water desorption were attributed to the reactions of hydrogen fluoride being a product of anion degradation with titanium and titanium oxide.

On the Interaction of Ionic Liquid 1-Butyl-3-Methylimidazolium Hexafluorophosphate with β-Cyclodextrin in Aqueous Solutions

2010 ◽  
Vol 224 (06) ◽  
pp. 893-906 ◽  
Author(s):  
Jakub Rak ◽  
Daniel Ondo ◽  
Marcela Tkadlecova ◽  
Vladimir Dohnal
Keyword(s):  
Ionic Liquid ◽  
Inclusion Complex ◽  
Aqueous Solutions ◽  
Room Temperature ◽  
Inorganic Salt ◽  
Formation Enthalpy ◽  
Titration Calorimetry ◽  
Imidazolium Cation ◽  
Phosphorus Nmr ◽  
Enthalpy And Entropy

AbstractThe formation of inclusion complex of β-cyclodextrin (β-CD) with the hydrophobic room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) in aqueous solutions was studied at 298.15 K using 1H, 13C, 19F and 31P NMR spectroscopy and isothermal titration calorimetry (ITC). Currently, there is a disagreement in the literature concerning the structure of the complex formed. In contrast to some results published recently in the literature, we found no reasonable support for β-CD to form an inclusion complex with 1-butyl-3-methyl-imidazolium cation of bmimPF6 in water. Our measurements on bmimPF6, the ionic liquid 1-butyl-3-methylimidazolium chloride (bmimCl), and the inorganic salt potassium hexafluorophosphate (KPF6) consistently support the formation of a weak 1:1 inclusion complex of β-CD with hexafluorophosphate anion instead of the bmim+ cation. The thermodynamic parameters of the respective complexation were calculated. The binding constant was evaluated from ITC and proton, fluorine and phosphorus NMR measurements, and the complex formation enthalpy and entropy were obtained from ITC.

scholarly journals Biodegradable Cellulose Film Prepared From Banana Pseudo-Stem Using an Ionic Liquid for Mango Preservation

2021 ◽  
Vol 12 ◽  
Author(s):  
Binling Ai ◽  
Lili Zheng ◽  
Wenqi Li ◽  
Xiaoyan Zheng ◽  
Yang Yang ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Gas Permeability ◽  
Transmission Rate ◽  
Packing Material ◽  
Cellulose Film ◽  
Promising Alternative ◽  
Moisture Vapor ◽  
Long Term Preservation ◽  
Gas Transmission Rate

The excessive use and disposal of plastic packaging materials have drawn increasing concerns from the society because of the detrimental effect on environment and ecosystems. As the most widely used fruit packing material, polyethylene (PE) film is not suitable for long-term preservation of some tropical fruits, such as mangos, due to its inferior gas permeability. Cellulose based film can be made from renewable resources and is biodegradable and environmental-friendly, which makes it a promising alternative to PE as a packaging material. In this study, cellulose film synthesized from delignified banana stem fibers via an ionic liquid 1-Allyl-3-methylimidazolium chloride ([AMIm][Cl]) were evaluated as packing material for mangos preservation. The moisture vapor transmission rate and gas transmission rate of the synthesized cellulose film were 1,969.1 g/(m2⋅24 h) and 10,015.4 ml/(m2⋅24 h), respectively, which are significantly higher than those of commercial PE films. The high permeability is beneficial to the release of ethylene so that contribute to extend fruit ripening period. As a result, cellulose film packaging significantly decreased the disease and color indexes of mangos, while prolonged the storage and shelf life of marketable fruits. In addition, the cellulose film was decomposed in soils in 4 weeks, indicating an excellent biodegradability as compared to the PE plastic film.

Phase Equilibria and Dissociation Enthalpies of Methane Hydrate in Imidazolium Ionic Liquid Aqueous Solutions

2015 ◽  
Vol 54 (46) ◽  
pp. 11701-11708 ◽  
Author(s):  
Zhen Long ◽  
Xuebing Zhou ◽  
Xiaodong Shen ◽  
Dongliang Li ◽  
Deqing Liang
Keyword(s):  
Ionic Liquid ◽  
Aqueous Solutions ◽  
Phase Equilibria ◽  
Methane Hydrate ◽  
Imidazolium Ionic Liquid

High concentration DNA solubility in bio-ionic liquids with long-lasting chemical and structural stability at room temperature

RSC Advances ◽  
2015 ◽  
Vol 5 (51) ◽  
pp. 40546-40551 ◽  
Author(s):  
Mukesh Sharma ◽  
Dibyendu Mondal ◽  
Nripat Singh ◽  
Nitin Trivedi ◽  
Jitkumar Bhatt ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Structural Stability ◽  
Chemical Stability ◽  
Room Temperature ◽  
High Concentration ◽  
One Year

DNA (Salmon testes) was solubilized in a biocompatible ionic liquid at up to 8 wt% with long term (one year) structural and chemical stability upon storage at room temperature.

Long-Term Correlations In Diffusive Motion Of Water Molecules And Rare Gas Atoms In Helium And Argon Aqueous Solutions

2015 ◽  
Vol 60 (8) ◽  
pp. 757-763 ◽  
Author(s):  
V.P. Voloshin ◽  
◽  
G.G. Malenkov ◽  
Yu.I. Naberukhin ◽  
◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Rare Gas ◽  
Water Molecules ◽  
Diffusive Motion ◽  
Rare Gas Atoms

Problems of treatment of primary openangle glaucoma in combination with thrombosis of the central retinal vein

GlaucomaNews ◽  
2020 ◽  
pp. 65-69
Author(s):  
T.E. Lipatkina ◽  
◽  
Е.V. Karlova ◽  
A.V. Zolotarev ◽  
◽  
...  
Keyword(s):  
Macular Edema ◽  
Primary Open Angle Glaucoma ◽  
Antihypertensive Drugs ◽  
Open Angle Glaucoma ◽  
Vascular Wall ◽  
Open Angle ◽  
Retinal Edema ◽  
Long Term Preservation ◽  
Central Retinal Vein

Patients with primary open-angle glaucoma (POAG) and ophthalmic hypertension have an increased likelihood of developing occlusions (thrombosis) of the central retinal vein. Different groups of antihypertensive drugs differ in their mechanism of action and may affect concomitant ocular pathology, in particular, retinal edema, which occurs, for example, in occlusion of the central retinal vein. Used in most patients with glaucoma, prostaglandin analogs can contribute to the long-term preservation of macular edema due to the effect on the permeability of the vascular wall. Preparations of other pharmacological groups, reducing the production of aqueous humor, on the contrary, may contribute to its regression. Therefore, the question of choosing a drug for antihypertensive therapy in patients with primary open-angle glaucoma and concomitant macular edema is relevant and is for further study.

Sign in / Sign up

Export Citation Format

Share Document