scholarly journals Immobilization of Peroxidase onto Magnetite Modified Polyaniline

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Eduardo Fernandes Barbosa ◽  
Fernando Javier Molina ◽  
Flavio Marques Lopes ◽  
Pedro Antonio García-Ruíz ◽  
Samantha Salomão Caramori ◽  
...  
Keyword(s):  
Horseradish Peroxidase ◽  
Initial Activity ◽  
Active Protein ◽  
Optimum Ph ◽  
Repeated Use

The present study describes the immobilization of horseradish peroxidase (HRP) on magnetite-modified polyaniline (PANImG) activated with glutaraldehyde. After the optimization of the methodology, the immobilization of HRP on PANImG produced the same yield (25%) obtained for PANIG with an efficiency of 100% (active protein). The optimum pH for immobilization was displaced by the effect of the partition of protons produced in the microenvironment by the magnetite. The tests of repeated use have shown that PANImG-HRP can be used for 13 cycles with maintenance of 50% of the initial activity.

scholarly journals Acid Stable Yeast Cell-Associated Tannase with High Capability in Gallated Catechin Biotransformation

2021 ◽  
Vol 9 (7) ◽  
pp. 1418
Author(s):  
Nalapat Leangnim ◽  
Jakkrit Aisara ◽  
Kridsada Unban ◽  
Chartchai Khanongnuch ◽  
Apinun Kanpiengjai
Keyword(s):  
Half Life ◽  
Debaryomyces Hansenii ◽  
Epigallocatechin Gallate ◽  
Initial Activity ◽  
Epicatechin Gallate ◽  
Candida Sp ◽  
Optimum Ph ◽  
Repeated Use ◽  
Temperature Optima ◽  
Acid Stable

Previously, nine tannin-tolerant and tannase-producing yeasts were isolated from Miang; all produced cell-associated tannase (CAT) during growth in tannin substrate. Among which, only CAT from Sporidiobolus ruineniae showed better stability than its purified form. Yet, it is of particular interest to directly characterize CATs from the latter yeasts. In this study, four CATs from yeasts, namely Cyberlindnera rhodanensis A22.3, Candida sp. A39.3, Debaryomyces hansenii A45.1, and Cy. rhodanensis A45.3 were characterized. The results indicate that all CATs were produced within the same production yield (11 mU/mL). Most CATs exhibited similar pH and temperature optima and stabilities, except for CAT from Cy. rhodanensis A22.3. This CAT was assigned as acid-stable tannase due to its unusual optimum pH of 2.0 with pH stability and half-life thermostability in the range of pH 2.0–4.0, and 70 °C, respectively. All CATs demonstrated high substrate specificity toward epigallocatechin gallate and epicatechin gallate, thus forming epigallocatechin and epicatechin, respectively. Moreover, they showed operational stability to repeated use for up to five cycles without loss of the initial activity. Therefore, CATs from these yeasts could be useful for the extraction and biotransformation of tea catechins and related applications.

scholarly journals Immobilization of alpha-amylase produced by Bacillus circulans GRS 313

2003 ◽  
Vol 46 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Gargi Dey ◽  
Singh Bhupinder ◽  
Rintu Banerjee
Keyword(s):  
Calcium Alginate ◽  
Immobilized Enzyme ◽  
Fold Increase ◽  
Alginate Beads ◽  
Hydrolysis Kinetics ◽  
Initial Activity ◽  
Reaction Conditions ◽  
Bead Size ◽  
Optimum Ph ◽  
Optimum Ph And Temperature

A maltooligosaccharide-forming amylase from B circulans GRS 313 was immobilized by entrapment in calcium alginate beads. The immobilized activity was affected by the size of the bead and bead size of 2mm was found to be most effective for hydrolysis. Kinetics constants, Km and Vmax were estimated and were found to be affected by the bead size. The catalytic activity of the enzyme was studied in presence of various starchy residues and metal ions. HgCl2, CuSO4 and FeCl3 caused inhibition of the enzyme. The reaction conditions, pH and temperature, was optimized using response surface methodology. At the optimum pH and temperature of 4.9 and 57ºC, the apparent activity was 25.6U/g of beads, resulting in almost 2-fold increase in activity. The immobilized enzyme showed a high operational stability by retaining almost 85% of the initial activity after seventh use.

scholarly journals Facile Bioinspired Preparation of Fluorinase@Fluoridated Hydroxyapatite Nanoflowers for the Biosynthesis of 5′-Fluorodeoxy Adenosine

2020 ◽  
Vol 12 (1) ◽  
pp. 431
Author(s):  
Ningning Li ◽  
Bingjing Hu ◽  
Anming Wang ◽  
Huimin Li ◽  
Youcheng Yin ◽  
...  
Keyword(s):  
Synthetic Activity ◽  
Initial Activity ◽  
Organofluorine Compounds ◽  
X Ray Diffraction ◽  
Green Method ◽  
X Ray ◽  
Fluoridated Hydroxyapatite ◽  
Optimum Ph ◽  
Ft Ir ◽  
Thermal Stability Of

To develop an environmentally friendly biocatalyst for the efficient synthesis of organofluorine compounds, we prepared the enzyme@fluoridated hydroxyapatite nanoflowers (FHAp-NFs) using fluorinase expressed in Escherichia coli Rosetta (DE3) as the biomineralization framework. The obtained fluorinase@FHAp-NFs were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and FT-IR spectrum and used in the enzymatic synthesis of 5′-fluorodeoxy adenosin with S-adenosyl-L-methionine and fluoride as substrate. At an optimum pH of 7.5, fluorinase confined in the hybrid nanoflowers presents an approximately 2-fold higher synthetic activity than free fluorinase. Additionally, after heating at 30 °C for 8 h, the FHAp-NFs retained approximately 80.0% of the initial activity. However, free enzyme could remain only 48.2% of its initial activity. The results indicate that the fluoride and hybrid nanoflowers efficiently enhance the catalytic activity and thermal stability of fluorinase in the synthesis of 5′-fluorodeoxy adenosine, which gives a green method for producing the fluorinated organic compounds.

scholarly journals Production of glucose and fructose syrups from cassava (Manihot esculenta Crantz) starch using enzymes produced by microorganisms isolated from Brazilian Cerrado soil

2010 ◽  
Vol 30 (1) ◽  
pp. 213-217 ◽  
Author(s):  
Roberto do Nascimento Silva ◽  
Fábio Pereira Quintino ◽  
Valdirene Neves Monteiro ◽  
Eduardo Ramirez Asquieri
Keyword(s):  
Aspergillus Niger ◽  
Manihot Esculenta ◽  
Glucose Isomerase ◽  
Cassava Starch ◽  
Maximum Activity ◽  
Brazilian Cerrado ◽  
Initial Activity ◽  
Manihot Esculenta Crantz ◽  
Streptomyces Sp ◽  
Optimum Ph

The high demands for sugars and the development of enzymatic technology have increased the production of sweeteners, especially for glucose and fructose syrups. This work describe a technology for glucose and fructose syrups from Brazilian cassava starch using enzymes produced by soil microrganisms isolated from the Brazilian Cerrado soil. Firstly, Aspergillus niger and Streptomyces sp. were isolated from the soil and used as glucoamylase (GA) and glucose isomerase (GI) producer sources. After characterization, GA and GI exhibited optimum pH 4.5 and 8.0, respectively. GA showed maximum activity at 60 ºC and GI at 85 ºC. GA and GI retained 65 and 80%, respectively, of initial activity after 180 minutes of incubation at 60 ºC. The kinetic parameters Km and Vmáx were 0.476 (mg.mL-1) and 8.58 (µmol/minute) for GA and 0.082 (M) and 48.20 (µmol/minute) for GI. The maximum glucose syrups production occurred after 24 hours of reaction with a 98% yield. The production of fructose syrups with 42% (w/v) was reached after 96 hours of reaction.

scholarly journals Covalent immobilization of an alkaline protease from Bacillus licheniformis

2018 ◽  
Vol 43 (6) ◽  
pp. 595-604
Author(s):  
Yakup Aslan ◽  
Derya Ömerosmanoğlu ◽  
Eda Öndül Koç
Keyword(s):  
Bacillus Licheniformis ◽  
Immobilized Enzyme ◽  
Milk Proteins ◽  
Covalent Immobilization ◽  
Initial Activity ◽  
Optimum Conditions ◽  
Continuous Processes ◽  
Operational Conditions ◽  
Optimum Ph ◽  
Soluble Enzymes

Abstract Objective Since the soluble enzymes can not be used in repeated reactions and are not stable in operational conditions and not suitable for continuous processes, this study aimed the covalent immobilization of Bacillus licheniformis protease (BLP) onto Eupergit CM. Methods Optimum conditions for immobilization were determined by changing the conditions individually. The proteins and L-tyrosine were determined by UV/VIS spectrophotometer. Results The immobilization resulted in 100% immobilization and 107.7% activity yields. The optimum pH (7–8) and the optimum temperature (70°C) have not changed after immobilization. The Km values for free and immobilized enzyme were 26.53 and 37.59 g/L, while the Vmax values were 2.84 and 3.31 g L-Tyrosine/L·min, respectively. The immobilized enzyme has not lost its initial activity during the repeated 20 uses and 20 days of storage. The milk proteins were hydrolyzed in 2 h by using immobilized enzyme. The pH of the milk dropped from 6.89 to 6.53, the color was clearer but there was no change in the smell or the taste. Conclusion Consequently, it can be said that the immobilized BLP obtained can be used for industrial purposes.

Optimum Conditions for Lipase Immobilization on Halloysitum Rubrum

2013 ◽  
Vol 864-867 ◽  
pp. 465-471
Author(s):  
Tao Deng ◽  
Jun Wei Xu ◽  
Li Huang ◽  
Tao Li ◽  
Xu Ya Yu
Keyword(s):  
Response Surface Methodology ◽  
Experimental Design ◽  
Immobilized Lipase ◽  
Candida Rugosa ◽  
Initial Activity ◽  
Optimum Conditions ◽  
Lipase Immobilization ◽  
Support Materials ◽  
Optimum Ph ◽  
Support Ratio

In this study, we use natural halloysitum rubrum as novel support materials to immobilize Candida rugosa lipase. The response surface methodology with a four-factor three-level Box-Behnken experimental design was used to evaluate the effects of immobilization parameters, such as pH (4.0 to 6.0), immobilization temperature (25 °C to 35 °C), enzyme/support ratio (0.1 to 0.3, w/w), and immobilization time (1 h to 2 h), on the activity of immobilized lipase. The optimum pH, temperature, enzyme/support ratio, and time for immobilized lipase activity (376.09 U/g) were 5.17, 29.65 °C, 0.3 (w/w), and 1.63 h, respectively. After 15 repeated uses, the immobilized lipase still retained 80% of its initial activity, which indicates good reusability.

scholarly journals Peroxidase from peach fruit: thermal Stability

1998 ◽  
Vol 41 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Valdir Augusto Neves ◽  
E. J. Lourenço
Keyword(s):  
Sucrose Concentration ◽  
Residual Activity ◽  
Deae Cellulose ◽  
Heat Stability ◽  
Initial Activity ◽  
Fast Inactivation ◽  
Peach Fruit ◽  
Optimum Ph ◽  
Calculated Activation Energy ◽  
Calculated Activation

Peroxidase from peach fruit was purified 28.9-fold by DEAE-cellulose, Sephadex G-100 and hydroxylapatite chromatography. The purified enzyme showed only one peak of activity with an optimum pH of 5.0 and temperature of 40ºC. The calculated activation energy (Ea) for the reaction was 7.97 kcal/mol. The enzyme was heat-labile in the temperature range of 60 to 80ºC with a fast inactivation at 80ºC. PAGE of the inactivation course at 70ºC showed only one band of activity. Different sugars increased the heat stability of the activity in the following order: sucrose>lactose>glucose>fructose. Measurement of residual activity showed a stabilizing effect of sucrose at various temperature/sugar concentrations (10 to 40%, w/w) with the Ea for inactivation increasing with sucrose concentration from 0 to 20% (w/w). After inactivation at 70ºC and 75ºC the enzyme was able to be reactivated by up to 40% of the initial activity when stored at 30ºC.

scholarly journals Immobilized Horseradish Peroxidase on Discs of Polyvinyl Alcohol-Glutaraldehyde Coated with Polyaniline

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Samantha Salomão Caramori ◽  
Kátia Flávia Fernandes ◽  
Luiz Bezerra de Carvalho Junior
Keyword(s):  
Horseradish Peroxidase ◽  
Polyvinyl Alcohol ◽  
Soluble Enzyme ◽  
Initial Activity

Discs of network polyvinyl alcohol-glutaraldehyde (PVAG) were synthesized and coated with polyaniline (PANI) using glutaraldehyde as a chemical arm (PVAG-PANIG-HRP disc). The best conditions for the immobilization were established as about 1.0 mg mL−1of protein, for 60 min and pH 5.5. The soluble enzyme lost all of its activity after incubation at 70°C for 15 min, whereas the PVAG-PANIG-HRP disc retained about half of the initial activity for pyrogallol. The same PVAG-PANIG-HRP disc was used consecutively three times without any activity lossbut presented 25% of the initial activity after the 7th use. PVAG-PANIG-HRP disc retained approximately 80% and 60% of its initial activity after 60 and 80 days of storage, respectively. Resorcinol, m-cresol, catechol, pyrogallol,α-naphthol,βnaphthol, and 4, 4′-diaminodiphenyl benzidine were efficiently oxidized by the PVAG-PANIG-HRP disc (from about 70% to 90%), and it was less efficient towards aniline, phenol, and 2-nitrosonaphthol.

scholarly journals Assisted refolding of recombinant prochymosin with the aid of protein disulphide isomerase

1994 ◽  
Vol 301 (1) ◽  
pp. 17-20 ◽  
Author(s):  
B Tang ◽  
S Zhang ◽  
K Yang
Keyword(s):  
Active Form ◽  
Thiol Groups ◽  
Active Protein ◽  
Protein Disulphide Isomerase ◽  
Ph Values ◽  
Free Thiol ◽  
Optimum Ph

Protein disulphide isomerase (PDI) was shown to be able to accelerate the refolding of unfolded recombinant prochymosin and to enhance the overall yield of active protein. Unlike previous reports in this study PDI was found to be active at pH values as high as 11. The coincidence of the similar apparent optimum pH values of uncatalysed and PDI-catalysed reactions suggests that conditions favourable to spontaneous refolding of proteins may help PDI to catalyse thiol/disulphide interchange. Under the conditions described here no exogenously added dithiothreitol was required for PDI-catalysed renaturation, implying that the disulphide form of PDI was reduced to its active form by the free thiol groups in prochymosin molecules.

α-Amylase Aspergillus oryzae Immobilized on Modified Expanded Perlite

2014 ◽  
Vol 12 (1) ◽  
pp. 587-596 ◽  
Author(s):  
J. Rodriguez ◽  
F. Soria ◽  
H. Geronazzo ◽  
H. Destefanis
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aspergillus Oryzae ◽  
Immobilized Enzyme ◽  
Maximum Activity ◽  
Free Enzyme ◽  
Expanded Perlite ◽  
Initial Activity ◽  
Optimum Ph ◽  
Scanning Electron

Abstract The α-amylase from Aspergillus oryzae was immobilized covalently onto expanded perlite (EP) and modified EP by treatment with TiO2 (EP-TiO2), dye HE3B (EP-HE3B) polyethylene terephthalate (PET)-hydrazide (EP-PET) and magnetite (EP-magnetite). The modified EP was characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The supports were functionalized with aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA). The optimum pH for free and immobilized α-amylase was 5.5. Temperature of maximum activity for free enzyme and immobilized enzyme on EP-HE3B was 50°C. The immobilized enzyme in EP-APTES this value was 55°C. The immobilized α-amylase in EP-APTES and EP-HE3B-APTES exhibited better thermostability than free enzyme. The immobilized derivatives showed moderate operational stability by retaining 50% of initial activity after seven successive reuses.

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