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calcium-alginate
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Optimization of Asparaginase Immobilization on Carrier
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh , Iran (Supervisor) ; Kazemi, Akhtarolmolok (Supervisor)
Abstract
The enzyme L-asparaginase (L-asparagine amidohydroxylase , EC 3.5.1.1) is utilizable in the treatment of acute childhood lymphoblastic leukaemia. L-asparaginase catalyses the hydrolysis of the amino acid L- asparagines to L-aspartic acid and ammonia. Unlike normal cells,malignant cells which can only slowly synthesize L-asparagine , are killed by lacking exogenous supply. In contrast, normal cells are protected from Asn-starvation due to their ability to produce this amino acid.
In this study , L- asparaginase from E.coli, was immobilized onto a polymeric compound, poly(vinyl alcohol)(PVA) with cross-linking agent glutaraldehyde and calcium alginate beads .. Herein ,with the use of the...
In this study , L- asparaginase from E.coli, was immobilized onto a polymeric compound, poly(vinyl alcohol)(PVA) with cross-linking agent glutaraldehyde and calcium alginate beads .. Herein ,with the use of the...
Optimization of Lipase Immobilization
, M.Sc. Thesis Sharif University of Technology ; Aalemzadeh, Iran (Supervisor) ; Kazemi, Akhtarolmolouk (Supervisor)
Abstract
In this study, Pseudomonas aeruginosa BBRC-10036 was used for lipase production. The organism secreted the enzyme extracellulary. First of all, effect of initial pH of the culture broth on lipase activity was studied in order to determine the optimum condition for lipase production. After production, this enzyme must be separated from culture and after that the enzyme must be purified for using in analysis and industry. Different methods are used for purification of the enzyme. In this research, first precipitation was used and then this lipase has been purified by Ion exchange Chromatography leading to 2.33- fold purification and 11.47% recovery. In precipitation by acetone, maximum...
Investigation of biotechnological production of Vitamin C
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor)
Abstract
Vitamin C is an essential for the survival of human, animals and plants. Human and most animals can not produce vitamin C in their bodies, thus the need to produce vitamin C as a supplement is necessary. Nowadays, for the industrial production of vitamin C, two Chinese and Rychstyn methods are used, the first method is a two-step method which is accomplished biological and the second method is done chemically. In Chinese method, first step, which is the most important step is production of L-sorbose from D-sorbitol by Gluconobacter oxydans bacteria .Thus, in this study it was attempted to optimize the production of L-sorbose to be used in industrial production of L-ascorbic acid. In...
Optimization of l-asparaginase immobilization onto calcium alginate beads
, Article Chemical Engineering Communications ; Volume 204, Issue 2 , 2017 , Pages 216-220 ; 00986445 (ISSN) ; Alemzadeh, I ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
In this study, anti-leukemic enzyme L-asparaginase (E.C.3.5.1.1) from Escherichia coli ATCC 11303 was modified by the microencapsulation technique onto calcium alginate beads. Using response surface methodology (RSM), a three-level full factorial design, the values of concentration of sodium alginate, concentration of calcium chloride, and enzyme loading were investigated to obtain the highest residual L-asparaginase (L-ASNase) activity % (immobilized enzyme activity/free enzyme activity). The effects of the studied factors on immobilization were evaluated The predicted values by the model were close to the experimental values, indicating suitability of the model. The results presented that...
Synthesis and characterization of new biopolymeric microcapsules containing DEHPA-TOPO extractants for separation of uranium from phosphoric acid solutions
, Article Journal of Microencapsulation ; Volume 28, Issue 4 , 2011 , Pages 248-257 ; 02652048 (ISSN) ; Tayyebi, A ; Khanchi, A ; Grayeli, F ; Bagheri, G ; Sharif University of Technology
Abstract
A novel microcapsule adsorbent for separation of uranium from phosphoric acid solutions was developed by immobilizing the di(2-ethylhexyl) phosphoric acid-trioctyl phosphine oxide extractants in the polymeric matrix of calcium alginate. Physical characterization of the microcapsules was accomplished by scanning electron microscopy and thermogravimetric techniques. Equilibrium experiments revealed that both ion exchange and solvent extraction mechanisms were involved in the adsorption of ions, but the latter prevailed in a wider range of acid concentration. According to the results of kinetics study, at low acidity level, the rate controlling step was slow chemical reaction of ions with the...
Effect of cell concentration on the acylation of penicillin G enzymatic reaction in immobilized cells
, Article Scientia Iranica ; Volume 16, Issue 1 , 2009 , Pages 69-73 ; 10263098 (ISSN) ; Otadi, M ; Khorasheh, F ; Kheirolomoom, A ; Sharif University of Technology
2009
Abstract
E.coli was immobilized by entrapment within calcium alginate beads using cell suspensions of different concentrations. The immobilization procedure resulted in beads with a homogeneous cell distribution, referred to as a Non-overlapping Cell (NC) configuration. If cells within the beads were allowed to grow, the NC configuration would transform into a Clustered Cell (CC) configuration as a, result of cell growth. Enzyme activity and substrate conversion were obtained for NC and CC configurations of different cell density, using penicillin G acylation by penicillin G acylase, to produce. 6-amino penicillanic acid. Enzyme activity and conversion were found to depend on both cell concentration...
A simple granulation technique for preparing high-porosity nano copper oxide(II) catalyst beads
, Article Particuology ; Volume 9, Issue 5 , 2011 , Pages 480-485 ; 16742001 (ISSN) ; Outokesh, M ; Hosseinpour, M ; Mousavand, T ; Sharif University of Technology
Abstract
A simple and efficient method was developed for fabricating spherical granules of CuO catalyst via a three-step procedure. In the first step, copper oxide nanoparticles were synthesized by hydrothermal decomposition of copper nitrate solution under supercritical condition. Then, they were immobilized in the polymeric matrix of calcium alginate, and followed by high-temperature calcination in an air stream as the third step, in which carbonaceous materials were oxidized, to result in a pebble-type catalyst of high porosity. The produced CuO nanoparticles were characterized by transmission electron microscopy (TEM) that revealed an average size of 5 nm, X-ray diffractometry (XRD), and thermo...
Synthesis and characterization of a bentonite-alginate microspherical adsorbent for removal of uranyl ions from aqueous Solutions
, Article Separation Science and Technology ; Volume 45, Issue 2 , 2010 , Pages 288-298 ; 01496395 (ISSN) ; Khanchi, A ; Ghofrani, M.B ; Outokesh, M ; Sharif University of Technogy
2010
Abstract
A novel microspherical adsorbent for the removal of uranium from aqueous solutions was developed by immobilizing of natural bentonite in the polymeric matrix of calcium alginate. Different uptake properties of the prepared microspheres were examined using batch, stirred and column methods. The adsorbent showed high affinity toward uranium ions, especially at pHs above 3. Major uptake mechanisms included ion exchange, chelating of the (UO2)2+ ions to the -OH groups of alginate, and surface complexation with bentonite. Surprisingly, the capacity of microspheres was higher than both its constituents, revealing that a synergetic effect occurs. Adsorption kinetics was controlled by slow chemical...
Phenols removal by immobilized horseradish peroxidase
, Article Journal of Hazardous Materials ; Volume 166, Issue 2-3 , 2009 , Pages 1082-1086 ; 03043894 (ISSN) ; Nejati, S ; Sharif University of Technology
2009
Abstract
Application of immobilized horseradish peroxidase (HRP) in porous calcium alginate (ca-alginate) for the purpose of phenol removal is reported. The optimal conditions for immobilization of HRP in ca-alginate were identified. Gelation (encapsulation) was optimized at 1.0% (w/v) sodium alginate in the presence of 5.5% (w/v) of calcium chloride. Upon immobilization, pH profile of enzyme activity changes as it shows higher value at basic and acidic solution. Increasing initial phenol concentration results in a decrease in % conversion. The highest conversion belongs to phenol concentration of 2 mM. Investigation into time course of phenol removal for both encapsulated and free enzymes showed...