Hydrolysis of Cellulose in the Presence of Catalysts Based on Cesium Salts of Heteropolyacids

2020 ◽  
Vol 20 (3) ◽  
pp. 234-242
Author(s):  
N. V. Gromov ◽  
T. B. Medvedeva ◽  
O. P. Taran ◽  
M. N. Timofeeva ◽  
V. N. Parmon
Keyword(s):  
Specific Surface ◽  
Active Component ◽  
Main Product ◽  
Catalytic Properties ◽  
Maximum Yield ◽  
Argon Atmosphere ◽  
Hydrolysis Of Cellulose ◽  
Cesium Salts ◽  
Hydrolysis Of ◽  
Catalyst Efficiency

The catalytic properties of cesium salts of heteropolyacids with the composition Cs4-хHхSiW12O40 (х = 3 and 3.5), Cs3-хHхPMo12O40 and Cs3-хHхPW12O40 (х = 2 and 2.5) were studied in the hydrolysis of cellulose to glucose at 180 °C in an argon atmosphere. Glucose was shown to be the main product of the reaction. The maximum yield reached 23% in the presence of Cs3HSiW12O40 for 1 h of the reaction. Specific surface area was supposed to affect the catalyst efficiency. It was found that in the presence of the indicated salts the reaction is heterogeneous and homogeneous, which is caused by leaching of the active component to the solution. The obtained materials were shown to be more efficient in comparison with the systems reported in the literature.

Hydrolysis of Cellulose in the Presence of Catalysts Based on Cesium Salts of Heteropoly Acids

2021 ◽  
Vol 13 (1) ◽  
pp. 73-80
Author(s):  
N. V. Gromov ◽  
T. B. Medvedeva ◽  
O. P. Taran ◽  
M. N. Timofeeva ◽  
V. N. Parmon
Keyword(s):  
Heteropoly Acids ◽  
Hydrolysis Of Cellulose ◽  
Cesium Salts ◽  
Hydrolysis Of

On the Preparation of Bovine α-Thrombin

1978 ◽  
Vol 39 (01) ◽  
pp. 193-200 ◽  
Author(s):  
Erwin F Workman ◽  
Roger L Lundblad
Keyword(s):  
Immobilized Enzyme ◽  
Catalytic Properties ◽  
Specific Activity ◽  
Guanidine Hydrochloride ◽  
Low Molecular Weight ◽  
Reversible Process ◽  
Gel Beads ◽  
Tissue Thromboplastin ◽  
C 50 ◽  
Hydrolysis Of

SummaryAn improved method for the preparation of bovine α-thrombin is described. The procedure involves the activation of partially purified prothrombin with tissue thromboplastin followed by chromatography on Sulfopropyl-Sephadex C-50. The purified enzyme is homogeneous on polyacrylamide discontinuous gel electrophoresis and has a specific activity toward fibrinogen of 2,200–2,700 N.I.H. U/mg. Its stability on storage in liquid media is dependent on both ionic strenght and temperature. Increasing ionic strength and decreasing temperature result in optimal stability. The denaturation of α-thrombin by guanidine hydrochloride was found to be a partially reversible process with the renatured species possessing properties similar to “aged” thrombin. In addition, the catalytic properties of a-thrombin covalently attached to agarose gel beads were also examined. The activity of the immobilized enzyme toward fibrinogen was affected to a much greater extent than was the hydrolysis of low molecular weight, synthetic substrates.

Immobilized Nanoparticles-Mediated Enzymatic Hydrolysis of Cellulose for Clean Sugar Production: A Novel Approach

2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai
Keyword(s):  
Catalytic Activity ◽  
Enzymatic Hydrolysis ◽  
Immobilized Enzyme ◽  
Free Enzyme ◽  
Magnetic Nanomaterials ◽  
Sugar Production ◽  
Cellulase Enzyme ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.

In Situ Microscopy for In-line Monitoring of the Enzymatic Hydrolysis of Cellulose

2013 ◽  
Vol 85 (17) ◽  
pp. 8121-8126 ◽  
Author(s):  
Britta Opitz ◽  
Andreas Prediger ◽  
Christian Lüder ◽  
Marrit Eckstein ◽  
Lutz Hilterhaus ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Enhanced Hydrolysis of Cellulose to Reducing Sugars on Kaolinte Clay Activated by Mineral Acid

2021 ◽  
Author(s):  
Yuxiao Dong ◽  
Dongshen Tong ◽  
Laibin Ren ◽  
Xingtao Chen ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Mineral Acid ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

scholarly journals Ni-γ-AL2O3 catalysts for obtaining nanocarbon by decomposition of natural gas

2021 ◽  
Author(s):  
Hikmet Ibrahimov ◽  
Sara Malikli ◽  
Zenfira Ibrahimova ◽  
Rahim Babali ◽  
Sevinc Aleskerova
Keyword(s):  
Natural Gas ◽  
Specific Surface ◽  
Catalytic Converter ◽  
Sol Gel ◽  
Nickel Content ◽  
Maximum Yield ◽  
Methane Decomposition ◽  
Impregnation Method ◽  
Decomposition Of Methane ◽  
Gas Supply

Abstractγ-Al2O3 was synthesized by the Sol–gel method, Ni (NO3)2 was placed in the pores by the impregnation method, and Ni-γ-Al2O3 was obtained by pyrolysis in a hydrogen stream in a CVD device. By the method of chemical vapors phase deposition (CVD) on Ni-Al2O3 catalytic converter with decomposition of methane in the natural gas produced carbon nanotubes (CNT) (Chunduri et al. in Mater Express 4(3):235–241, 2014; Zhou et al. in Appl Catal B 208:44–59, 2017). The catalytic activity of the catalysts in methane decomposition was examined from 650 °C to 900 °C by the method of chemical vapors phase deposition (CVD), the yield of CNTs tends to increase with the growth at the ratio of natural gas supply to hydrogen. The specific surface increases with an increase of nickel content and can reach 265.5 m2/g for a sample of 2% Ni-A12O3 at 850 °C. Growth at the temperature of methane decomposition leads to reduction in its specific surface. It has been established that the use of the Ni-Cu/γ-Al2O3 catalytic system, in which copper acts as a stabilizing additive, makes it possible to double the maximum yield of the carbon product during the decomposition of natural gas.

Fabrication of Bifunctional SiO2/Europium-Polyoxometalates/Ag Particles and their Luminescence and Catalysis Properties

2013 ◽  
Vol 575-576 ◽  
pp. 216-224
Author(s):  
Jun Wang ◽  
Shao Hua Fan ◽  
Wei Qian Zhao ◽  
Wu Ke Li ◽  
Xue Lian Lu
Keyword(s):  
Main Product ◽  
Catalytic Properties ◽  
Uv Light ◽  
Luminescent Properties ◽  
Silica Spheres ◽  
Hybrid Particles ◽  
Red Emission ◽  
Transmission Electron ◽  
Ag Particles ◽  
Luminescent Spectra

In this paper, Stöber silica particles were decorated with polyethyleneimine and silver nanoparticles and Eu-polyoxometalates were grafted on the surface of polyethyleneimine/silica spheres. The hybrid SiO2/Eu-polyoxometalates/Ag particles were characterized by IR, UVvis, luminescent spectra, scanning electron microscopy, transmission electron microscope, and cyclic voltammetry (CV), respectively. The hybrid particles show the bright red emission under UV light which can be observed by naked eyes. The luminescent properties of particles have been investigated which show that Ag nanoparticles have an influences on the luminescence of europium ions. The electrochemical activities of SiO2/Eu-polyoxometalates/Ag particles have been demonstrated by CV measurement. The catalytic results indicate that the hybrid particles show the catalytic properties in the oxidation of styrene and benzaldehyde is the main product of the reaction.

Role and significance of beta-glucosidases in the hydrolysis of cellulose for bioethanol production

2013 ◽  
Vol 127 ◽  
pp. 500-507 ◽  
Author(s):  
Reeta Rani Singhania ◽  
Anil Kumar Patel ◽  
Rajeev K. Sukumaran ◽  
Christian Larroche ◽  
Ashok Pandey
Keyword(s):  
Bioethanol Production ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of
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