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    Immobilization of cellulase on non-porous ultrafine silica particles

    , Article Scientia Iranica ; Volume 14, Issue 4 , 2007 , Pages 379-383 ; 10263098 (ISSN) Afsahi, B ; Kazemi, A ; Kheirolomoom, A ; Nejati, S ; Sharif University of Technology
    Sharif University of Technology  2007
    Abstract
    The immobilization of cellulase onto non-porous ultrafine silica particles was studied. Cellulase was extracted from a Trichoderma reesei culture after partial purification with ammonium sulfate (pH = 5.0), which was then immobilized onto non-porous ultrafine silica particles, with or without the use of glutaraldehyde as a crosslinking agent. Cellulase was immobilized by adsorption onto ultrafine silica particles efficiently, as well as by covalent cross-linking with glutaraldehysde. Increasing the concentration of the free form of enzyme increased the amount of immobilized cellulase. The maximum enzyme immobilization happened at the free enzyme concentration of 0.48 mg/ml. In general, the... 

    Immobilization of α -chymotrypsin on the surface of magnetic/gold core/shell nanoparticles

    , Article Journal of Nanotechnology ; Volume 2013 , 2013 ; 16879503 (ISSN) Kamal Ahmadi, M ; Vossoughi, M ; Sharif University of Technology
    Hindawi Publishing Corporation  2013
    Abstract
    Over the last decade, nanoparticles used as protein carriers have opened new avenues for a variety of biomedical applications. The main concern for these applications is changes in biological activity of immobilized proteins due to conformational changes on the surface of the carrier. To evaluate this concern, the preparation and biocatalyst activity of α-chymotrypsin-Fe 3O4 @ Au core/shell nanoparticles were investigated. First, Fe3O4 @ Au core/shell nanoparticles were synthesized by coprecipitation method and citrate reduction of HAuCl 4. TEM imaging revealed a core size of 13 ± 3 nm and a shell thickness of 4 ± 1 nm for synthesized nanoparticles. X-ray diffraction (XRD) was used to study... 

    Novel type of two-impinging-jets reactor for solid-liquid enzyme reactions

    , Article AIChE Journal ; Volume 52, Issue 2 , 2006 , Pages 692-704 ; 00011541 (ISSN) Molaei Dehkordi, A ; Sharif University of Technology
    2006
    Abstract
    The isomerization of D-glucose to D-fructose using the immobilized glucose isomerase, as a typical model system of solid-liquid enzyme reactions has been carried out in a novel type of two-impinging-jets reactor (TIJR), which is characterized by a rotating inner cylinder in a stationary one. Because of the impinging process, turbulence, and complex trajectory of the solid particles within the reactor, the fractional conversion of glucose obtained in the TIJR increased dramatically compared to that obtained by conventional reaction systems. A compartment model was considered to describe the pattern of flow [residence time distribution (RTD) of solid particles] within the TIJR. Considering... 

    Co-Immobilization of Multi-Enzyme Cascade System into the Metal-Organic Frameworks (MOFs)for the Removal of Microcontaminants and Process Equipment Layout

    , M.Sc. Thesis Sharif University of Technology Babaei, Hassan (Author) ; Farhadi, Fatolla (Supervisor) ; Yaghmaei, Soheila (Supervisor) ; Ghobadiejad, Zahra (Co-Supervisor)
    Abstract
    In recent years, the biodegradation of micro-contaminants using enzymes has attracted the attention of many researchers in the field of environment and health. Micro- and nano-scale environments play an important role in enzymatic catalysis that directly affects the activity and stability of enzymes. Therefore, setting a nanoscale environment for enzymes is very important, especially in liquids with undesirable properties (such as pH, temperature, toxicity, etc.) in this work, a method proposed in which the pH and the substrate concentration are regulated for enzymatic catalysis using a metal-organic framework, consisting of Glucose Oxidase (GOx) and Horseradish Peroxidase (HRP) immobilized... 

    Covalent immobilization of cellulase using magnetic poly(ionic liquid) support: improvement of the enzyme activity and stability

    , Article Journal of Agricultural and Food Chemistry ; Volume 66, Issue 4 , 2018 , Pages 789-798 ; 00218561 (ISSN) Hosseini, H ; Hosseini, A ; Zohreh, N ; Yaghoubi, M ; Pourjavadi, A ; Sharif University of Technology
    American Chemical Society  2018
    Abstract
    A magnetic nanocomposite was prepared by entrapment of Fe3O4 nanoparticles into the cross-linked ionic liquid/epoxy type polymer. The resulting support was used for covalent immobilization of cellulase through the reaction with epoxy groups. The ionic surface of the support improved the adsorption of enzyme, and a large amount of enzyme (106.1 mg/g) was loaded onto the support surface. The effect of the presence of ionic monomer and covalent binding of enzyme was also investigated. The structure of support was characterized by various instruments such as FT-IR, TGA, VSM, XRD, TEM, SEM, and DLS. The activity and stability of immobilized cellulase were investigated in the prepared support. The... 

    Influence of phosphate anions on the stability of immobilized enzymes. Effect of enzyme nature, immobilization protocol and inactivation conditions

    , Article Process Biochemistry ; Volume 95 , August , 2020 , Pages 288-296 Kornecki, J. F ; Carballares, D ; Morellon Sterling, R ; Siar, E. H ; Kashefi, S ; Chafiaa, M ; Arana Peña, S ; Rios, N. S ; Gonçalves, L. R. B ; Fernandez Lafuente, R ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    A destabilizing effect at pH 7 of sodium phosphate on several lipases immobilized via interfacial activation is shown in this work. This paper investigates if this destabilizing effect is extended to other inactivation conditions, immobilization protocols or even other immobilized enzymes (ficin, trypsin, β-galactosidase, β-glucosidase, laccase, glucose oxidase and catalase). As lipases, those from Candida antarctica (A and B), Candida rugosa and Rhizomucor miehei have been used. Results confirm the very negative effect of 100 mM sodium phosphate at pH 7.0 for the stability of all studied lipases immobilized on octyl agarose, while using glutaraldehyde-support the effect is smaller (still... 

    Alkaline protease production by immobilized cells using B. licheniformis

    , Article Scientia Iranica ; Volume 20, Issue 3 , 2013 , Pages 607-610 ; 10263098 (ISSN) Maghsoodi, V ; Kazemi, A ; Nahid, P ; Yaghmaei, S ; Sabzevari, M. A ; Sharif University of Technology
    2013
    Abstract
    In recent years there has been potential increase in the use of alkaline protease as industrial catalysts. Many major industrial and commercial applications, such as food and textile industries, and medical diagnoses, are highly dependent on the protease enzyme. In the cell immobilization technique, the free movement of microorganisms is restricted in the process, and a continuous system of fermentation can be used. In the present work, this technique has been used for alkaline protease production using different carriers, such as chitosan, corn cob and corn tassel. Enzyme activity before immobilization (72 h) was 78.3 U/ml. Corn cob, with 65% immobilization capacity and the highest enzyme... 

    Development and verification of a model to describe an immobilized glucose isomerase packed bed bioreactor

    , Article Biochemical Engineering Journal ; Volume 40, Issue 2 , 2008 , Pages 328-336 ; 1369703X (ISSN) Khalilpour, R ; Roostaazad, R ; Sharif University of Technology
    2008
    Abstract
    In this paper, the performance of immobilized packed bed glucose isomerase enzyme was mathematically modeled. A modified Michaelis-Menten type relation was used to describe the enzyme kinetics. Mass transfer inside the biocatalyst particle and through the bed column was analyzed simultaneously. Using measured data, physicochemical properties including diffusivity, viscosity and density of sugar solutions were correlated with its concentrations and were used to provide precision in solving the set of model equations. Model equations were solved using the Runge-Kutta and Gauss-Seidel algorithms and finite difference numerical method in MATLAB environment. Model output was used to demonstrate... 

    Immobilization of penicillin G acylase on non-porous ultrafine silica particles

    , Article Scientia Iranica ; Volume 12, Issue 3 , 2005 , Pages 295-299 ; 10263098 (ISSN) Fazelinia, H ; Kheirolomoom, A ; Sharif University of Technology
    Sharif University of Technology  2005
    Abstract
    In this paper, immobilization of penicillin G aclylase onto non-porous ultrafine silica particles has been studied. The amount of penicillin G acylase immobilized was increased by increasing the free enzyme concentration and, at 0.45 mg/ml concentration of the free enzyme, 80% of the enzyme was immobilized. The optimum pH for immobilization was found to be 7.0, close to the pl of the enzyme. Although immobilization of the enzyme on ultrafine silica particles with and without glutaraldehyde showed almost the same activities, the enzyme immobilized with glutaraldehyde retained its initial activity much longer during 40 cycle-repeated batches with a half life of 163.2 h. © Sharif University of... 

    Phenols removal by immobilized horseradish peroxidase

    , Article Journal of Hazardous Materials ; Volume 166, Issue 2-3 , 2009 , Pages 1082-1086 ; 03043894 (ISSN) Alemzadeh, I ; 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... 

    Amperometric sulfide detection using Coprinus cinereus peroxidase immobilized on screen printed electrode in an enzyme inhibition based biosensor

    , Article Biosensors and Bioelectronics ; Volume 35, Issue 1 , 2012 , Pages 297-301 ; 09565663 (ISSN) Savizi, I. S. P ; Kariminia, H. R ; Ghadiri, M ; Roosta Azad, R ; Sharif University of Technology
    2012
    Abstract
    In the present work, an amperometric inhibition biosensor for the determination of sulfide has been fabricated by immobilizing Coprinus cinereus peroxidase (CIP) on the surface of screen printed electrode (SPE). Chitosan/acrylamide was applied for immobilization of peroxidase on the working electrode. The amperometric measurement was performed at an applied potential of -150. mV versus Ag/AgCl with a scan rate of 100. mV in the presence of hydroquinone as electron mediator and 0.1. M phosphate buffer solution of pH 6.5. The variables influencing the performance of sensor including the amount of substrate, mediator concentration and electrolyte pH were optimized. The determination of sulfide... 

    Magnetite nanoparticle as a support for stabilization of chondroitinase ABCI

    , Article Artificial Cells, Nanomedicine and Biotechnology ; Volume 47, Issue 1 , 2019 , Pages 2721-2728 ; 21691401 (ISSN) Askaripour, H ; Vossoughi, M ; Khajeh, K ; Alemzadeh, I ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Abstract
    Chondroitinase ABCI (cABCI) is a drug enzyme that can be used to treat spinal cord injuries. Due to low thermal stability of cABCI, this enzyme was immobilized on Fe3O4 nanoparticle to increase its thermal stability. The size and morphology, structure and magnetic property of the Fe3O4 nanoparticles were characterized by the analyses of SEM, XRD and VSM, respectively, and FTIR spectroscopy was employed to confirm the immobilization of cABCI on the surface of Fe3O4 nanoparticles. The results indicated that the optimum conditions for pH, temperature, cABCI-to-Fe3O4 mass ratio and incubation time in immobilization process were 6.5, 15 °C, 0.75 and 4.5 h, respectively, and about 0.037 mg cABCI... 

    Removal of bisphenol A in aqueous solution using magnetic cross-linked laccase aggregates from Trametes hirsuta

    , Article Bioresource Technology ; Volume 306 , 2020 Sadeghzadeh, S ; Ghobadi Nejad, Z ; Ghasemi, S ; Khafaji, M ; Borghei, S. M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Enzymatic removal of Bisphenol A (BPA), acknowledged as an environmentally friendly approach, is a promising method to deal with hard degradable contaminants. However, the application of “enzymatic treatment” has been limited due to lower operational stability and practical difficulties associated with recovery and recycling. Enzyme immobilization is an innovative approach which circumvents these drawbacks. In this study, laccase from Trametes hirsuta was used for BPA removal. Amino-functionalized magnetic Fe3O4 nanoparticles were synthesized via the co-precipitation method followed by surface modification with (3-aminopropyl)trimethoxysilane (APTMS). The as-prepared nanoparticles were... 

    Pharmaceuticals removal by immobilized laccase on polyvinylidene fluoride nanocomposite with multi-walled carbon nanotubes

    , Article Chemosphere ; Volume 263 , 2021 ; 00456535 (ISSN) Masjoudi, M ; Golgoli, M ; Ghobadi Nejad, Z ; Sadeghzadeh, S ; Borghei, S. M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    The presence of pharmaceutical micropollutants in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, biodegradation of pharmaceuticals using enzymes such as laccase, is proposed as a green method. In this study, immobilized laccase was used for the removal of two model pharmaceutical compounds, carbamazepine and diclofenac. Polyvinylidene fluoride (PVDF) membrane modified with multi-walled carbon nanotubes (MWCNTs) were synthesized as a tailor-made support for enzyme immobilization. Covalently immobilized laccase from Trametes hirsuta exhibited remarkable activity and activity recovery of 4.47 U/cm2 and 38.31%, respectively. The results also... 

    Evaluation of biodiesel production using lipase immobilized on magnetic silica nanocomposite particles of various structures

    , Article Biochemical Engineering Journal ; Volume 79 , 2013 , Pages 267-273 ; 1369703X (ISSN) Kalantari, M ; Kazemeini, M ; Arpanaei, A ; Sharif University of Technology
    2013
    Abstract
    Nonporous and mesoporous silica-coated magnetite cluster nanocomposites particles were fabricated with various silica structures in order to develop a desired carrier for the lipase immobilization and subsequent biodiesel production. Lipase from Pseudomonas cepacia was covalently bound to the amino-functionalized particles using glutaraldehyde as a coupling agent. The hybrid systems that were obtained exhibited high stability and easy recovery regardless of the silica structure, following the application of an external magnetic field. The immobilized lipases were then used as the recoverable biocatalyst in a transesterification reaction to convert the soybean oil to biodiesel with methanol.... 

    Spectrophotometric determination of sulfide based on peroxidase inhibition by detection of purpurogallin formation

    , Article Ecotoxicology and Environmental Safety ; Volume 91 , 2013 , Pages 117-121 ; 01476513 (ISSN) Ghadiri, M ; Kariminia, H. R ; Roosta Azad, R ; Sharif University of Technology
    2013
    Abstract
    This paper presents a new method for spectrophotometirc detection of sulfide applying fungal peroxidase immobilized on sodium alginate. The sensing scheme was based on decrease of the absorbance of the orange compound, purpurogallin produced from pyrogallol and H2O2 as substrates, due to the inhibition of peroxidase by sulfide. Absorbance of purpurogallin was detected at 420nm by using a spectrophotometer. The proposed method could successfully detect the sulfide in the concentration range of 0.6-7.0μM with a detection limit of 0.4μM. The kinetic parameters of Michaelis-Menten with and without sulfide were also calculated. Possible inhibition mechanism of peroxidase by sulfide was deduced... 

    Amine-functionalized magnetic nanocomposite particles for efficient immobilization of lipase: effects of functional molecule size on properties of the immobilized lipase

    , Article RSC Advances ; Volume 5, Issue 42 , Apr , 2015 , Pages 33313-33327 ; 20462069 (ISSN) Esmaeilnejad Ahranjani, P ; Kazemeini, M ; Singh, G ; Arpanaei, A ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    A cost-effective design of reusable enzyme-functionalized particles with better catalytic activity is of great scientific interest due to their applications in a wide range of catalytic reactions in several industrial processes. In this work, a systematic approach for preparing amine-functionalized magnetic nanocomposite particles through the surface modification of core/shell type Fe3O4 cluster@SiO2 particles by the small molecules of 3-(2-aminoethyl)aminopropyltrimethoxysilane (AAS) or the large molecules of polyethyleneimine (PEI) with two different molecular weights, as the support materials for enzyme immobilization, has been demonstrated. The functional... 

    Optimization of l-asparaginase immobilization onto calcium alginate beads

    , Article Chemical Engineering Communications ; Volume 204, Issue 2 , 2017 , Pages 216-220 ; 00986445 (ISSN) Bahraman, F ; 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... 

    Covalently immobilized laccase onto graphene oxide nanosheets: Preparation, characterization, and biodegradation of azo dyes in colored wastewater

    , Article Journal of Molecular Liquids ; Volume 276 , 2019 , Pages 153-162 ; 01677322 (ISSN) Kashefi, S ; Borghei, S. M ; Mahmoodi, N. M ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    In this study, graphene oxide (GO) was synthesized via modified Hummer's method and exploited as an ideal enzyme immobilization support due to its exclusive chemical and structural features. Then, laccase from genetically modified Aspergillus was covalently immobilized onto GO (nanobiocatalyst). Enzymatic characterization of the nanobiocatalyst exhibited promising results: laccase loading of 156.5 mg g−1 and immobilization yield of 64.6% at laccase concentration of 0.9 mg/ mL. Further employment of various structural characterization techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Thermo-Gravimetric... 

    Immobilization of laccase from trametes hirsuta onto CMC coated magnetic nanoparticles

    , Article International Journal of Engineering, Transactions A: Basics ; Volume 33, Issue 4 , 2020 , Pages 513-519 Sadeghzadeh, S ; Ghazvini, S ; Hejazi, S ; Yaghmaei, S ; Ghobadi Nejad, Z ; Sharif University of Technology
    Materials and Energy Research Center  2020
    Abstract
    In this study Fe3O4/CMC magnetic nanoparticles were synthesized through co-precipitation method. Afterward, laccase from Trametes hirsuta was immobilized onto Carboxymethyl cellulose (CMC)-coated magnetic Fe3O4 nanoparticles by covalent bonding between carboxyl groups of carboxymethyl cellulose and amine group of laccases. Also, the resulted magnetic nanoparticles and immobilized laccase were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and dynamic light scattering (DLS) analysis. Moreover, the vital factors in enzyme immobilization, such as contact time, amount of N-hydroxysuccinimide (NHS), and the amount of nanoparticles were...