Function Of Surfactants In Immobilization of Cellulase And Multiphase Hydrolysis: A Review

2021 ◽  
Author(s):  
Zhiquan Wang ◽  
Deyi Wu ◽  
Xinze Wang ◽  
Hainan Kong
Keyword(s):  
Reaction System ◽  
Current Status ◽  
Diffusion Resistance ◽  
Solid Contact ◽  
Active Centers ◽  
Oriented Immobilization ◽  
Oil Water ◽  
Hydrolysis Of ◽  
Micelle System ◽  
Broad Overview

Abstract Surfactants, especially non-ionic surfactants, play an important role in the preparation of nanocarriers and can also promote the enzymatic hydrolysis of lignocellulose. A broad overview of the current status of surfactants on the immobilization of cellulase is provided in this review. In addition, the restricting factors in cellulase immobilization in the complex multiphase hydrolysis system are discussed, including the carrier structure characteristics, solid-solid contact obstacles, external diffusion resistance, limited recycling frequency, and invalid combination of enzyme active centers. Furthermore, promising prospects of cellulase-oriented immobilization are proposed, including the hydrophilic-hydrophobic interaction of surfactants and cellulase in the oil-water reaction system, the reversed micelle system of surfactants, and the possible oriented immobilization mechanism.

Effect of acidity on the properties of silica-aluminas synthesized by sol-gel method

2020 ◽  
Vol 63 (7) ◽  
pp. 126-132
Author(s):  
Lyubov V. Furda ◽  
◽  
Evgenia A. Tarasenko ◽  
Sofya N. Dudina ◽  
Olga E. Lebedeva ◽  
...  
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Molar Ratio ◽  
Active Centers ◽  
Indicator Method ◽  
Synthesis Conditions ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Amphoteric Properties ◽  
Hydrolysis Of

In the present work amorphous silica-aluminas were synthesized by the coprecipitation method during the hydrolysis of an alcohol solution of tetraethoxysilane (with a tetraethoxysilane: alcohol mass ratio of 1: 1) and 6% aqueous solution of aluminum nitrate at pH values of 1, 3, and 10. The Si/Al molar ratio for all synthesized samples were 4.72 (± 0.29). The amorphous character of the investigated materials was confirmed by X-ray phase analysis. According to the results of scanning electron microscopy, it was found that the resulting powders have particles with a size of 1-20 μm. It was shown that the conditions of synthesis affected the specific surface area and porosity of the materials under study. By the method of low-temperature adsorption-thermodesorption of nitrogen it was established that silica-aluminas obtained under acidic conditions were microporous materials. For the sample obtained under alkaline conditions (pH = 10), the contribution of macropores is very significant. A decrease in surface area is observed as the pH of the synthesis increases. The Hammett indicator method was used to identify and quantify surface centers of different acidity. All studied silica-aluminas are characterized by the presence of both Brønsted basic (pKax from 7 to 12.8) and acidic (pKax from 0 to 7) centers, and Lewis basic (pKax from -4.4 to 0) with a pronounced maximum at pKax = 1.02. It was found that the synthesis conditions had a significant effect on the concentration of active centers. The values of the Hammett function are practically the same for the 3 studied silica-aluminas and describe the studied samples as materials of medium acidity. The variety of Lewis and Brønsted centers on the surface indicates the amphoteric properties of the materials under study. This gives the samples the properties of polyfunctional sorbents and catalysts.

Resin Material Used in Methyl Acrylate Hydrolysis Reaction

2014 ◽  
Vol 1035 ◽  
pp. 307-312 ◽  
Author(s):  
Ya Ping Li ◽  
Quan Huo ◽  
Cun Cun Zuo ◽  
Sha Sha Cao ◽  
Er Qiang Wang
Keyword(s):  
Experimental Data ◽  
Methyl Acrylate ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Reaction System ◽  
Ion Exchange Resin ◽  
High Energy ◽  
Molar Ratio ◽  
Resin Catalyst ◽  
Hydrolysis Of

In this work, the ion exchange resin catalyst named D072 were used in the hydrolysis of a methyl acrylate to acrylic acid and methanol firstlyand chemical equilibrium would be achieved during the process of the reversible reaction system. The influences of parameters such as dosage of catalyst, initial reactants molar ratio and reaction temperature were investigated. Meanwhile, the reusability of cation-exchange resin was studied, and no phenomenon of deactivation was found with using of reused catalyst. Moreover, the experimental data were analyzed by the pseudo-homogeneous (PH) model and the hydrolysis dynamics equation of methyl acrylate was obtained and found that the activation energy of the reaction was 118.37 KJ/mol in the presence of D072. Based on the result, high energy would be needed to the hydrolysis of methyl acrylate in using D072 resin as catalyst.

Hydrolysis of BNPP Catalyzed by the Dodecyliminodiacetate Nickel(II) and Copper(II) Complexes

2013 ◽  
Vol 749 ◽  
pp. 507-511
Author(s):  
Sheng Tian Huang ◽  
Shen Xin Li ◽  
Ying Wang ◽  
Song Wu ◽  
Wei Hu
Keyword(s):  
Kinetic Parameter ◽  
Temperature Effect ◽  
Absorption Spectra ◽  
Reaction System ◽  
Catalytic Hydrolysis ◽  
Specific Absorption ◽  
Reaction Systems ◽  
Nitrophenyl Phosphate ◽  
Hydrolytic Reaction ◽  
Hydrolysis Of

Two novel dodecyliminodiacetate nickel (II) and copper (II) complexes were synthesized and characterized, and these complexes were used as mimic hydrolytic in catalytic hydrolysis of bis (p-nitrophenyl) phosphate (BNPP). The analysis of specific absorption spectra of the hydrolytic reaction systems indicated that the catalytic hydrolysis involved the key intermediates formed by BNPP with nickel (II) complexes. The kinetic parameter of BNPP catalytic hydrolysis has been calculated and the temperature effect of reaction system and structure effect of the complexes on the rate of BNPP hydrolysis catalyzed by the complexes have been discussed.

Preferential in vivo accumulation of sn-2,3-diacylglycerols in postheparin plasma of rats

1977 ◽  
Vol 55 (10) ◽  
pp. 1075-1081 ◽  
Author(s):  
N. Morley ◽  
A. Kuksis ◽  
A. G. D. Hoffman ◽  
G. Kakis
Keyword(s):  
Portal Vein ◽  
Lipoprotein Lipase ◽  
Hepatic Lipase ◽  
Water Interface ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Oil Water ◽  
Hydrolysis Of

The stereochemical course of in vivo hydrolysis of triacylglycerols by lipoprotein lipase was investigated by determining the structure of diacylglycerol intermediates in postheparin plasma of rats which had been fed [3H]glycerol-labeled Intralipid 2 h before an injection of heparin or had been given an injection of a mixture of [3H]glycerol-Intralipid and heparin. During the clearance of both the natural chylomicrons and the artificial emulsion, sn-2,3-diacylglycerols (60–80%) were found to be the dominant enantiomers. Similar results were obtained when the contribution of the hepatic lipase was altered, either by tying off the mesentery artery and portal vein before injection of heparin, or by injection of heparin directly into the portal vein. These findings are consistent with a preferential release of the acyl group from the sn-1 position of the triacylglycerol molecule as demonstrated previously in vitro. A preferential orientation of the substrate in the enzyme–substrate complex or at the oil–water interface is discussed as a possible basis for these effects.

Germanium Dioxide Nanocubes with Different Size Distributions and Its Gibbs Free Energy Theory

2011 ◽  
Vol 688 ◽  
pp. 135-140 ◽  
Author(s):  
H. Wang ◽  
Y. Tao ◽  
G.Q. Zhang ◽  
Y.P. Xia ◽  
F.H. Gong ◽  
...  
Keyword(s):  
Free Energy ◽  
Size Distribution ◽  
Gibbs Free Energy ◽  
Synthesis Method ◽  
Germanium Dioxide ◽  
Size Distributions ◽  
Bimodal Size Distribution ◽  
Energy Theory ◽  
Hydrolysis Of ◽  
Micelle System

A simple synthesis method for single crystal GeO2 nanocubes in a reverse micelle system was reported here. Hydrolysis of germanium tetrachloride (GeCl4) in a micelle system produces GeO2nanocubes in the presence of oleylamine and cetyltrimethylammonium (CTAB). We found that we could obtain GeO2nanocubes with monodisperse size distribution, bimodal size distribution and polydisperse size distribution by varying the reaction parameters. We put forward a feasible explain for this phenomenon with using Gibbs free energy theory, and this theory can give some meaningful guidance for preparing monodisperse nanomaterials.

scholarly journals On the Mechanism of Formation of Conversion Titanium-Containing Coatings

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 328 ◽  
Author(s):  
Aleksey Abrashov ◽  
Nelya Grigoryan ◽  
Tigran Vagramyan ◽  
Naum Asnis
Keyword(s):  
Steel Substrate ◽  
Titanium Oxides ◽  
Active Centers ◽  
Continuous Film ◽  
Solution Flow ◽  
Linear Rate ◽  
Titanium Coatings ◽  
First Time ◽  
Aluminum Surfaces ◽  
Hydrolysis Of

The present work is devoted to the study of the mechanism of the process of formation of adhesive oxide-titanium coatings on steel, zinc, and aluminum surfaces. For the first time, the following hypothesis has been confirmed experimentally, namely, that nickel, being the first metal to be deposited on a steel substrate, creates active centers on which titanium oxides are formed, because the hydrolysis of hexafluorotitanic acid is adsorbed, which then form a continuous film. The data obtained, regarding the dependence of the coating thickness on the linear rate of the solution flow along the treated surface, indirectly confirm that the formation of insoluble titanium oxides occurs because of the alkalization of the solution adjacent to the surface. It has been established that in the presence of hexavalent molybdenum compounds in the solution as oxidizers, molybdenum is included in the coating in the form of oxides. It has been revealed that in the lower layers of the coating, molybdenum is contained in the form of compounds of molybdenum (V) and (VI), while in the upper layers, it is contained only in the form of the compound of molybdenum (VI).

scholarly journals Subunit separation in reversed micelle system reveals the existence of active centers both on light and heavy γ-glutamyltransferase subunits

FEBS Letters ◽  
1991 ◽  
Vol 295 (1-3) ◽  
pp. 73-76 ◽  
Author(s):  
Alexander V. Kabanov ◽  
Sergey N. Nametkin ◽  
Nikolai N. Chernov ◽  
Natalya L. Klyachko ◽  
Andrey V. Levashov
Keyword(s):  
Reversed Micelle ◽  
Active Centers ◽  
Micelle System
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