Effects of organic solvents on immobilized enzyme catalyses. Chymotrypsin immobilized on porous glass

1981 ◽  
Vol 59 (19) ◽  
pp. 2921-2925 ◽  
Author(s):  
J. Bryan Jones ◽  
Diana H. Pliura
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Porous Glass ◽  
Immobilized Enzyme ◽  
Butyl Alcohol ◽  
Solvent Concentration ◽  
Marked Contrast ◽  
Practical Applications ◽  
Tert Butyl Alcohol ◽  
Esterolytic Activity

The esterolytic activity of native chymotrypsin (CT) immobilized on ionically neutral porous glass beads has been studied in the presence of up to 20% (v/v) of the organic solvents methanol, ethanol, 2-propanol, tert-butyl alcohol, dioxane, and DMSO. In marked contrast to the variations observed with native CT, inhibition of CT immobilized on glass (CT–glass) was independent of the nature of the organic solvent. The overall activity, as indicated by kc(app)/km(app), decreased by 35–50% as the concentration of all solvents surveyed was increased up to 20%. In general, high organic solvent concentration accelerated the rate of protein release from the insoluble catalyst. For practical applications in aqueous organic solvents CT–glass conjugates are inferior to those of the enzyme attached to Sephadex.

Effects of organic solvents on immobilized enzyme catalyses. Chymotrypsin immobilized on Sephadex

1980 ◽  
Vol 58 (23) ◽  
pp. 2633-2640 ◽  
Author(s):  
Diana H. Pliura ◽  
J. Bryan Jones
Keyword(s):  
Enzyme Activity ◽  
Organic Solvents ◽  
Immobilized Enzyme ◽  
Reaction Medium ◽  
Butyl Alcohol ◽  
Native Enzyme ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Catalytic Rate ◽  
Hydrolysis Of

The esterolytic activities of native chymotrypsin (CT) and immobilized CT-Sephadex have been studied in the presence of up to 20% of the organic solvents methanol, ethanol, 2-propanol, tert-butyl alcohol, dioxane, or DMSO. The general cosolvent-induced inhibition of the native enzyme was attenuated for immobilized CT. Most noticeably, the apparent catalytic rate constants for the CT-Sephadex-catalyzed hydrolysis of N-acetyl-L-tyrosine ethyl ester were invariant over the 2–20% dioxane concentration range surveyed. In contrast, the activity of the native enzyme in 20% dioxane was only 3% the activity recorded in the absence of cosolvent. Increasing the hydrophobic character of the protic cosolvents destabilized the native enzyme but stabilized CT-Sephadex. Both native and immobilized CT displayed remarkable stability in 20% aqueous DMSO [Formula: see text]. At least part of the DMSO-induced inhibition of native CT and CT-Sephadex was offset by increasing the apparent pH of the reaction medium. The altered kinetic patterns for CT-Sephadex are best explained by the effects of diffusional limitations on the apparent enzyme activity. The best compromise solvent for preparative applications of CT-Sephadex was found to be tert-butyl alcohol.

Enzymes in organic synthesis. 23. Effects of organic solvents on horse liver alcohol dehydrogenase-catalyzed oxidation

1982 ◽  
Vol 60 (8) ◽  
pp. 1030-1033 ◽  
Author(s):  
J. Bryan Jones ◽  
Harold M. Schwartz
Keyword(s):  
Alcohol Dehydrogenase ◽  
Organic Synthesis ◽  
Organic Solvents ◽  
Butyl Alcohol ◽  
Horse Liver Alcohol Dehydrogenase ◽  
Liver Alcohol Dehydrogenase ◽  
Tert Butyl Alcohol ◽  
Horse Liver ◽  
Catalyzed Oxidation ◽  
Enzymes In Organic Synthesis

The effects have been evaluated of up to 50% (v/v) of methanol, tert-butyl alcohol, dimethylsulfoxide, sulfolane, acetonitrile, dimethylformamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, acetone, 2-butanone, tetrahydrofuran, dimethoxyethane, diglyme, and dioxane on horse liver alcohol dehydrogenase (HLADH)-catalyzed oxidation of the representative alcohol substrate cyclohexanol. With the exception of dimethylsulfoxide and dimethylformamide, all solvents tested are suitable for use as cosolvents with HLADH in the oxidative and reductive directions.

Coefficients B de viscosité dans les systèmes ternaires aqueux. III. Halogénures alcalins–alcool tert-butylique–eau à 25 °C

1979 ◽  
Vol 57 (24) ◽  
pp. 3247-3252 ◽  
Author(s):  
Marc Palma ◽  
Jean-Pierre Morel
Keyword(s):  
Linear Relationship ◽  
Structural Properties ◽  
Organic Solvents ◽  
Linear Correlation ◽  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Water ◽  
Coefficient Of Viscosity

We have measured the coefficient of viscosity B at 25 °C of HCl, LiCl, NaCl, KCl, RbCl, KI, and KBr in the mixtures of aqueous organic solvents containing from 10 to 40% tert-butyl alcohol by weight (X), the concentration of electrolyte varying from 0.1 to 0.3 M.Plots of B = f (x) show points of inflexion and minima whose positions can be explained by the structural properties of the mixed solvent.In water, a linear relationship between the entropy of hydration and coefficient B of the ions is observed. In the same way, it can be shown that a linear correlation exists between the entropy of solvation and coefficient B of the electrolytes for all the mixtures studied.These correlations lead to the characterization of two distinct zones (X < 20% and X > 20%) for the range of tert-butyl alcohol–water mixtures. [Journal translation]

Kinetics and mechanism of hydrolysis of substituted phenyl N-(4-methylphenyl)sulphonylcarbamates. Solvolysis of 3-nitrophenyl N-(4-methylphenyl)-sulphonylcarbamate in mixtures water-1,4-dioxane and water-tert-butyl alcohol and its decomposition to neutral molecules in non-aqueous media

1979 ◽  
Vol 44 (9) ◽  
pp. 2639-2652 ◽  
Author(s):  
Jitka Moravcová ◽  
Miroslav Večeřa
Keyword(s):  
Organic Solvents ◽  
Ph Dependence ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Base Catalysis ◽  
Hydrolysis Rate ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Hydrolysis Of

pH Dependence of hydrolysis rate of the substituted phenyl N-(4-methylphenyl)sulphonylcarbamates has been followed in aqueous medium. The activation parameters and the Hammet reaction constant (ρ = 2.4) have been determined at pH 11.3. For hydrolysis of 3-nitrophenyl N-(4-methylphenyl)sulphonylcarbamate (pK about 3.5) no general base catalysis has been found. The hydrolysis mechanism is discussed. Perturbation of the water structure by organic solvents (1,4-dioxane and tert-butyl alcohol) has been used for differentiation of ElcB and Bac2 mechanisms, 2,4-dinitrophenyl acetate being used for comparison. The decomposition rates of 3-nitrophenyl N(4-methylphenyl)sulphonylcarbamate have been determined in six organic solvents. Mechanism of spontaneous splitting of the carbamate molecule in non-aqueous media is discussed.

scholarly journals An organic solvent and surfactant stable α-amylase from soybean seeds.

2013 ◽  
Vol 60 (3) ◽  
Author(s):  
Nivedita Jaiswal ◽  
Om Prakash
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Immobilized Enzyme ◽  
Catalytic Efficiency ◽  
Free Enzyme ◽  
Tween 20 ◽  
Dimethyl Formamide ◽  
Soybean Seeds ◽  
Potential Candidate ◽  
Surfactant Stable

An organic solvent and surfactant stable α-amylase was obtained from soybean seeds. The direct and indirect effect of various organic solvents (non-polar, polar protic, and polar aprotic) and surfactants on the activity and stability of free enzyme was determined. The enzyme showed a very high catalytic efficiency and stabilization against most of the organic solvents and surfactants tested, except for few. Those organic solvents and surfactants (like chloroform, dimethyl formamide, n-butanol, and Tween 20), which caused an inhibition in enzyme activity, were used to study their effects on immobilized enzyme. The inhibitory effect was found to be decreased in immobilized enzyme as compared to free enzyme indicating that immobilization imparted stability to the enzyme. Moreover, the possibility of reuse of the enzyme in the presence of the organic solvents and surfactants was increased upon immobilization. The stability of soybean α-amylase towards organic solvents and surfactants shows that it is a potential candidate for use in organic-solvent biocatalysis as well as in detergent industries.

scholarly journals Recovery of Valuable Solutes from Organic Solvent/Water Mixtures via Direct Contact Membrane Distillation (DCMD) as a Non-Heated Process

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 559
Author(s):  
Yuki Suga ◽  
Ryosuke Takagi ◽  
Hideto Matsuyama
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Solvent Concentration ◽  
Polyvinylidene Difluoride ◽  
Vapor Flux ◽  
Solvent Water ◽  
Direct Contact Membrane Distillation ◽  
Increasing Temperature

Recently, the demand for the recovery of valuable solutes from organic solvents/water mixtures has increased in various fields. Furthermore, due to the abundance of heat-sensitive valuable solutes, the demand for non-heated concentration technologies has increased. In this study, the direct contact membrane distillation (DCMD) using hydrophobic polyvinylidene difluoride (PVDF) hollow fiber membranes was investigated to confirm the possibility of recovering valuable solutes from organic solvents/water mixtures as a non-heated process. The DCMD with 1000 ppm NaCl aqueous solution achieved 0.8 kg/m2·h of vapor flux and >99.9% of NaCl retention, even at feed and coolant temperatures of 25 and 10 °C, respectively. Furthermore, when DCMD was conducted under various conditions, including feed temperatures of 25, 35 and 45 °C, and organic solvent concentration of 15, 30 and 50 wt%, using ethanol/water and acetonitrile/water mixtures containing 1000 ppm NaCl. A surfactant was also used as a valuable solute, in addition to NaCl. As a result, it was found that the total vapor flux increased with increasing temperature and concentration of organic solvents, as the partial vapor pressure of the organic solvents increased. Additionally, no solute leaked under any condition, even when the surfactant was used as a valuable solute.

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

Transfer Thermodynamic Functions ∆Gt0, ∆Ht0 and T∆St0 of cis- and trans-[CoCl2(en)2]+ Isomers in Aqueous Mixtures of Methanol, tert-Butyl Alcohol and Acetonitrile

2000 ◽  
Vol 65 (9) ◽  
pp. 1455-1463
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Enthalpy Of Solution ◽  
Transfer Functions ◽  
Partial Molar Volumes ◽  
Butyl Alcohol ◽  
Aqueous Mixtures ◽  
Aqueous Methanol ◽  
Solvent Interactions ◽  
Tert Butyl Alcohol ◽  
Surface Charge Distribution ◽  
Cis And Trans

The solubility, partial molar volume and standard integral molar enthalpy of solution of cis- and trans-[CoCl2(en)2]Cl in water, aqueous methanol, aqueous tert-butyl alcohol and aqueous acetonitrile are reported. The transfer functions ∆Gt0, ∆Ht0 and T∆St0 as well as partial molar volumes are used to obtain information on the solute-solvent interactions. Results obtained are discussed in terms of differences in the surface charge distribution in isomeric coordination species.

scholarly journals Efficient Degradation of Mordant Blue 9 Using the Fenton-Activated Persulfate System

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2532 ◽  
Author(s):  
Md. Nahid Pervez ◽  
Felix Y. Telegin ◽  
Yingjie Cai ◽  
Dongsheng Xia ◽  
Tiziano Zarra ◽  
...  
Keyword(s):  
Butyl Alcohol ◽  
Textile Dye ◽  
Oh Radicals ◽  
Operational Parameters ◽  
Reaction Conditions ◽  
Tert Butyl Alcohol ◽  
Initial Ph ◽  
Fe Complex ◽  
Optimal Reaction ◽  
Activated Persulfate

In this study, a Fenton-activated persulfate (Fe2+/PS) system was introduced for the efficient degradation of Mordant Blue 9 (MB 9) as a textile dye in an aqueous solution. Results showed that the degradation of MB 9 was markedly influenced by operational parameters, such as initial pH, PS concentration, Fe2+ concentration, and initial dye concentration. Optimal reaction conditions were then determined. Inorganic anions, such as Cl− and HCO3−, enhanced the degradation efficiency of MB 9 under optimal conditions. Addition of HCO3− reduced the degradation performance of MB 9, whereas the addition of Cl− increased the degradation percentage of MB 9. In addition, quenching experiments were conducted using methanol and tert-butyl alcohol as scavengers, and methanol was identified as an effective scavenger. Thus, the degradation of MB 9 was attributed to S O 4 • − and •OH radicals. The degradation and mineralization efficiency of MB 9 was significantly reduced using the conventional Fenton process i.e., Fe2+/ hydrogen peroxide (HP) because of the formation of a Fe complex during degradation. Meanwhile, the Fe2+/persulfate (PS) system improved the degradation and mineralization performance.

scholarly journals Impacts of Sn(II) doping on the Keggin heteropolyacid-catalyzed etherification of glycerol with tert-butyl alcohol

2021 ◽  
pp. 116913
Author(s):  
Márcio José da Silva ◽  
Diego Morais Chaves ◽  
Sukarno Olavo ferreira ◽  
Rene Chagas da Silva ◽  
Jose Balena Gabriel Filho ◽  
...  
Keyword(s):  
Butyl Alcohol ◽  
Tert Butyl ◽  
Tert Butyl Alcohol
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