scholarly journals IMMOBILIZATION OF INVERTASE ON CARBOXYMETHYLCELLULOSE PREPARED FROM NATA DE COCO FOR THE INVERSION OF SUCROSE

2017 ◽  
Vol 20 (1) ◽  
pp. 37-47 ◽  
Author(s):  
E.O.V. Fundador ◽  
V.C. Sabularse Fundador ◽  
M.A.J.R. Revilleza
Keyword(s):  
Immobilized Enzyme ◽  
Colloidal Suspension ◽  
Initial Activity ◽  
Ionic Interaction ◽  
Acetobacter Aceti ◽  
Michaelis Constant ◽  
Temperature Changes ◽  
Pellet Formation ◽  
Optimum Ph ◽  
Continuous Use

Nata de coco, the cellulose produced by Acetobacter aceti with coconut water as substrate, was used as starting material in the synthesis of carboxymethylcellulose after treatment with NaOH and monochloroacetic acid. The product, referred to as carboxymethyl-“nata” (CMN), had a degree of substitution of 0.76, a higher value than those previously reported. This was used in the immobilization of invertase via ionic interaction and adsorptive forces, which produced a viscous colloidal suspension. Agar was incorporated to facilitate pellet formation. Interactions between the agar and the CMN-invertase may have resulted from ionic interactions as well as H-bonding. The immobilized enzyme retained 71% of its initial activity and exhibited optimum pH of 4.5 and an optimum temperature of 55°C. It was more sensitive to pH and temperature changes. The Michaelis constant, Km, was 107.43 mM for the immobilized enzyme, and 71.42 mM for the free enzyme. The Vmax values were 89.28 µmole min-1 and 82.64 µmole min for the free and immobilized enzyme, respectively. Statistical analyses showed that V values did not vary significantly. The higher K of the immobilized enzyme may be attributed to diffusional effects, steric hindrance and conformational modifications of the enzyme. The immobilized enzyme has potential for further applications because of its stability with storage, repeated and continuous use.

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 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.

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.

scholarly journals Effect of Cultivation Time and Medium Condition in Production of Bacterial Cellulose Nanofiber for Urease Immobilization

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
M. Pesaran ◽  
Gh. Amoabediny ◽  
F. Yazdian
Keyword(s):  
Bacterial Cellulose ◽  
Immobilized Enzyme ◽  
Cellulose Nanofibers ◽  
Immobilized Enzymes ◽  
Cellulose Nanofiber ◽  
Initial Activity ◽  
Enzyme Adsorption ◽  
Cultivation Medium ◽  
Optimum Ph ◽  
Urease Immobilization

A new nanoporous biomatrix originated from bacterial resources has been chosen for urease immobilization. Urease has been immobilized on synthesized bacterial cellulose nanofiber since this enzyme has a key role in nitrogen metabolism.Gluconacetobacter xylinumATCC 10245 has been cultivated for synthesis of a nanofiber with the diameter of 30–70 nm. Different cultivation processes in the aspect of time and cultivation medium conditions were chosen to study the performance of immobilized enzyme on four types of bacterial cellulose nanofibers (BCNs). Urease immobilization into the nanofiber has been done in two steps: enzyme adsorption and glutaraldehyde cross-linking. The results showed that the immobilized enzymes were relatively active and highly stable compared to the control samples of free enzymes. Optimum pH was obtained 6.5 and 7 for different synthesized BCNs, while the optimum temperature for immobilized urease was 50°C. Finding of the current experiment illustrated that the immobilized enzyme in optimum condition lost its initial activity by 41% after 15 weeks.

scholarly journals Immobilization of Catalase on Chitosan/ZnO and Chitosan/ZnO/Fe2O3 Nanocomposites: A Comparative Study

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 820
Author(s):  
Reda M. El-Shishtawy ◽  
Nahed S. E. Ahmed ◽  
Yaaser Q. Almulaiky
Keyword(s):  
Half Life ◽  
Immobilized Enzyme ◽  
Enzyme Stability ◽  
Catalytic Performance ◽  
Free Enzyme ◽  
Initial Activity ◽  
Reaction Systems ◽  
Optimum Ph ◽  
Immobilized Catalase ◽  
System Properties

The strong catalytic performance, eco-friendly reaction systems, and selectivity of enzyme-based biocatalysts are extremely interesting. Immobilization has been shown to be a good way to improve enzyme stability and recyclability. Chitosan-incorporated metal oxides, among other support matrices, are an intriguing class of support matrices for the immobilization of various enzymes. Herein, the cross-linked chitosan/zinc oxide nanocomposite (CS/ZnO) was synthesized and further improved by adding iron oxide (Fe2O3) nanoparticles. The final cross-linked CS/ZnO/Fe2O3 nanocomposite was used as an immobilized support for catalase and is characterized by SEM, EDS, and FTIR. The nanocomposite CS/ZnO/Fe2O3 enhanced the biocompatibility and immobilized system properties. CS/ZnO/Fe2O3 achieved a higher immobilization yield (84.32%) than CS/ZnO (37%). After 10 repeated cycles, the remaining immobilized catalase activity of CS/ZnO and CS/ZnO/Fe2O3 was 14% and 45%, respectively. After 60 days of storage at 4 °C, the remaining activity of immobilized enzyme onto CS/ZnO and CS/ZnO/Fe2O3 was found to be 32% and 47% of its initial activity. The optimum temperature was noticed to be broad at 25–30 °C for the immobilized enzyme and 25 °C for the free enzyme. Compared with the free enzyme optimum pH (7.0), the optimum pH for the immobilized enzyme was 7.5. The Km and Vmax values for the free and immobilized enzyme on CS/ZnO, and the immobilized enzyme on CS/ZnO/Fe2O3, were found to be 91.28, 225.17, and 221.59 mM, and 10.45, 15.87, and 19.92 µmole ml−1, respectively. Catalase immobilization on CS/ZnO and CS/ZnO/Fe2O3 offers better stability than free catalase due to the enzyme’s half-life. The half-life of immobilized catalase on CS/ZnO/Fe2O3 was between 31.5 and 693.2 min.

scholarly journals Encapsulation of HRP Enzyme onto a Magnetic Fe3O4 Np–PMMA Film via Casting with Sustainable Biocatalytic Activity

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 181 ◽  
Author(s):  
Wesam H. Abdulaal ◽  
Yaaser Q. Almulaiky ◽  
Reda M. El-Shishtawy
Keyword(s):  
Metal Ions ◽  
Immobilized Enzyme ◽  
Pmma Film ◽  
Optimum Temperature ◽  
Initial Activity ◽  
Casting Method ◽  
Ph Optimum ◽  
Optimum Ph ◽  
Triton X ◽  
Enzyme Changes

Horseradish peroxidase (HRP) enzyme was effectively encapsulated onto an Fe3O4 nanoparticle–polymethyl methacrylate (PMMA) film via the casting method. The HRP was immobilized on the 0.5% Fe3O4Np–PMMA film and characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Moreover, the reusability, thermal stability, optimum pH, optimum temperature, the influence of metal ions, and the effects of detergent and organic solvent were investigated. After optimizing the immobilization conditions, the highest efficiency of the immobilized enzyme was 88.4% using 0.5% Fe3O4Np–PMMA. The reusability of the immobilized HRP activity was 78.5% of its initial activity after being repeatedly used for 10 cycles. When comparing the free and immobilized forms of the HRP enzyme, changes in the optimum temperature and optimum pH from 30 to 40 °C and 7.0 to 7.5, respectively, were observed. The Km and Vmax for the immobilized HRP were estimated to be 41 mM, 0.89 U/mL for guaiacol and 5.84 mM, 0.66 U/mL for H2O2, respectively. The high stability of the immobilized HRP enzyme was obtained using metal ions, a high urea concentration, isopropanol, and Triton X-100. In conclusion, the applicability of immobilized HRP involves the removal of phenol in the presence of hydrogen peroxide, therefore, it could be a potential catalyst for the removal of wastewater aromatic pollutants.

β-GLUCURONIDASE OF RABBIT POLYMORPHONUCLEAR LEUCOCYTES

1950 ◽  
Vol 28e (3) ◽  
pp. 69-79 ◽  
Author(s):  
R. J. Rossiter ◽  
Esther Wong
Keyword(s):  
Enzyme Activity ◽  
Blood Plasma ◽  
Substrate Concentration ◽  
Final Concentration ◽  
White Cell ◽  
Polymorphonuclear Leucocytes ◽  
Michaelis Constant ◽  
Glucuronidase Activity ◽  
Arsanilic Acid ◽  
Optimum Ph

Rabbit polymorphonuclear leucocytes contain an enzyme capable of hydrolyzing biosynthetic phenolphthalein mono-β-glucuronide. The concentration of the enzyme in the white cell is some 2000 times the concentration of the enzyme in the blood plasma. Under the conditions of study, the β-glucuronidase activity was proportional to the concentration of the enzyme. The effect of substrate concentration on the enzyme activity was studied and the Michaelis constant, Ks, determined. The course of the reaction was linear with time for the first 12 hr. and then fell off slightly during the next 12 hr. The optimum pH of the enzyme was 4.45 in either 0.2 M acetate or 0.2 M phthalate buffer. It was not inhibited by cyanide, azide, iodoacetate, fluoride, glycine, thiourea, urethane, arsanilic acid, acetophenone, o-cresol or m-cresol, in a final concentration of 0.01 M. The possible function of β-glucuronidase in rabbit polymorphonuclear leucocytes is discussed.

Charakterisierung und Kinetik des in der Rattenplacenta vorkommenden mikrosomalen Enzyms, das den Wasserstoff-Transfer von Oestradiol auf Androstendion katalysiert / Characterization and Kinetics of the Microsomal Enzyme of Rat Placenta which Functions as a “Transhydrogenase” between Estradiol-17β and Androstenedione

1971 ◽  
Vol 26 (7) ◽  
pp. 710-719 ◽  
Author(s):  
Kunhard Pollow ◽  
Barbara Pollow
Keyword(s):  
Hydrogen Transfer ◽  
Microsomal Fraction ◽  
Close Relation ◽  
Inhibitory Effect ◽  
Magnesium Ions ◽  
Michaelis Constant ◽  
Temperature Optimum ◽  
Optimum Ph ◽  
Kinetics Of ◽  
Estradiol 17Β

The microsomal fraction of rat placenta contains a 17β-hydroxysteroid-oxidoreductase which transfers hydrogen from position 17 of estradiol to androstenedione. This hydrogen transfer is dependent on NAD, NADP as cofactor is without effect. The optimum pH is at 6,9. In the presence of NAD the Michaelis constant for estradiol is 4,17 · 10-5м at pH 7,4. In the presence of androstenedione in the incubation medium the Km-value for estradiol is decreased, which indicates an increased affinity for the enzyme. The temperature optimum of the enzyme is 38 °C. Addition of SH-blocking agents inhibited the enzyme activity. Zinc and magnesium ions had an inhibitory effect on the “transhydrogenase” and B-NADPT specifically labelled from [1-T]-glucose showed that the non-effect of NADP on transhydrogenation from estradiol to androstenedione resulting in reduction of position 17 is not due to different stereospecifity.The results show a close relation between the oxidative metabolism of estradiol and the reduction of androstenedione, indicating that estradiol-17β, as the preferred hydrogen-donating substrate, is an essential component of the androstenedione-hydrogenating system in the microsomal fraction of rat placenta.

scholarly journals Production of Aspartame by Immobilized Thermolysin

2019 ◽  
pp. 1232-1239
Author(s):  
Mohammed A Alsoufi ◽  
Raghad A. Aziz
Keyword(s):  
Reaction Time ◽  
Immobilized Enzyme ◽  
Bentonite Clay ◽  
Optimum Temperature ◽  
Initial Activity ◽  
Reaction Conditions ◽  
Original Activity ◽  
Ph Profile ◽  
Full Activity ◽  
Main Activity

The aim of this study was the production of aspartame by using immobilized thermolysin in bentonite clay. The yield of immobilized thermolysin in bentonite was 92% of the original enzyme amount. pH profile of free and immobilized enzyme was 7.0 and 7.5 respectively which was stable at 6.5-9.0 for 30min. The optimum temperature of both enzymes was 50°C, while they were stable at 65°C for 30min. however, they lost 52.73 and 61.72% from its main activity at 80°C respectively. Immobilized thermolysin has retained all activity within 27 days, but it kept 68.27% of initial activity when stored for 60 days at 4°C whereas, it retained a full activity after 20 continue usage. In addition, it retained 86.53% of its original activity after 30 continuing usages. The yield of produced aspartame was increased with reaction time; it was 9% after 1h and increased gradually to 100% after 10h at reaction conditions.

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