Co-Immobilization of Glucose Oxidase-Catalase: Optimization of Immobilization Parameters to Improve the Immobilization Yield

2011 ◽  
Vol 7 (2) ◽  
Author(s):  
Sandip B Bankar ◽  
Mahesh V Bule ◽  
Rekha S Singhal ◽  
Laxmi A Ananthanarayan
Keyword(s):  
Glucose Oxidase ◽  
Response Surface ◽  
Glass Bead ◽  
Cross Linking ◽  
Optimization Strategy ◽  
Composite Optimization ◽  
The Cross ◽  
Glass Surfaces ◽  
Central Composite ◽  
Potential Use

Co-immobilization of glucose oxidase (EC 1.1.3.4) and catalase (EC 1. 11.1.6) on non-porus glass surfaces using ?-aminopropyltriethoxysilane and polyethyleneimine as an activator and gluteraldehyde as cross linking agent has been carried out for its potential use. Polyethyleneimine was found to be a superior immobilization activator than ?-aminopropyltriethoxysilane. In present study, the effects of rough and smooth beads and optimization of the ratio of enzyme concentrations, activator material and concentration of the cross linking agent were investigated using response surface technology. With optimized concentration of glucose oxidase to catalase ratio (0.97), polyethyleneimine (150 mg/l) and gluteraldehyde (15 ml), the effect of glass bead concentration for maximum immobilization yield was investigated. Central composite optimization strategy with 16 experiments increased immobilization yield from 82.63% to 92.74%. It was observed that 0.3 ml of beads per 120 U of glucose oxidase were necessary for higher immobilization yield.

Optimal Study of Co-Immobilized GOD/CAT on Cross-Linked Chitosan Microsphere Containing L-Lysine

2011 ◽  
Vol 236-238 ◽  
pp. 926-929 ◽  
Author(s):  
Xiao Hua Zhou ◽  
Ying Li Wang ◽  
Xia Li Su
Keyword(s):  
Enzyme Activity ◽  
Glucose Oxidase ◽  
Half Life ◽  
Immobilized Enzyme ◽  
Activity Ratio ◽  
Cross Linking ◽  
Chitosan Microsphere ◽  
Activity Recovery ◽  
The Cross ◽  
Optimized Conditions

Glucose oxidase (GOD) and catalase (CAT) were co-immobilized on the cross-linked chitosan microsphere containing L-Lysine (CCL) by the method of absorption-crosslink, with cross-linking agent of glutaraldehyde. The optimized conditions of the co-immobilization are as follows: activity ratio of GOD and CAT is 0.78:1, concentration of glutaraldehyde is 0.17mmol/L, and the immobilizing process last for 3 hours. The enzyme activity of co-immobilized enzyme is 15.3U/mg and activity recovery is 50.1%. The half life is 231 days, 2.4 times of immobilized GOD.

scholarly journals Chemical cross-linking of a dimeric protein on a modified lectin matrix. A general probe for the chemical topology of oligomeric glycoproteins

1981 ◽  
Vol 193 (3) ◽  
pp. 825-828 ◽  
Author(s):  
S Pillai
Keyword(s):  
Glucose Oxidase ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Cross Linking ◽  
Low Density ◽  
Amino Groups ◽  
Lysine Residues ◽  
The Cross ◽  
Interfacial Surfaces ◽  
Chemical Cross Linking

A dimeric glycoprotein, glucose oxidase, was allowed to react with lysine-specific cross-linkers, both when immobilized on a succinoylated lectin matrix at a critically low density and also at a high density in solution. Analysis of the cross-linked complexes thus obtained led to the following inferences with regard to the structure of this protein. (1) Of the 15 lysine residues on each glucose oxidase protomer, none is available on the non-interfacial surfaces. (2) Assuming that this protein possesses C2 symmetry with isologous bonding between subunits, it may be inferred that on each promoter there are at least two lysine clusters along or close to the interprotomeric interface. (3) These ‘interfacial’ lysine residues on each protomer are so oriented that the epsilon-amino groups of lysine residues a and b on protomer 1 ‘face’, and are very close to, the epsilon-amino groups of lysine residues b' and a' respectively on protomer 2. General inferences on the geometry of dimeric proteins derivable from an analysis of the cross-linked complexes obtained (as well as those not seen) by using this low-density matrix cross-linking approach were enumerated. Modified lectin matrices may prove useful in studying the three-dimensional structure of glycoproteins, particularly non-crystallizable oligomers.

Enzyme-assisted Extraction for Optimized Recovery of Phenolic Bioactives from Peganum hermala Leaves Using Response Surface Methodology

2018 ◽  
Vol 17 (4) ◽  
pp. 349-354
Author(s):  
Qadir Rahman ◽  
Anwar Farooq ◽  
Amjad Gilani Mazhar ◽  
Nadeem Yaqoob Muhammad ◽  
Ahmad Mukhtar
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Enzyme Concentration ◽  
Coumaric Acid ◽  
Assisted Extraction ◽  
Pre Treatment ◽  
Optimized Conditions ◽  
Enzyme Complexes ◽  
Hydrolysis Of ◽  
Central Composite

This study investigates the effect of enzyme formulations (Zympex-014, Kemzyme dry-plus and Natuzyme) on recovery of phenolics from Peganum hermala (harmal) leaves, under optimized conditions using response surface methodology. As compared to the other enzyme complexes, the yield (34 g/100g) obtained through Zympex-014-assisted extraction was higher under optimized conditions such as time (75 min), temperature (70°C), pH (6.5) and enzyme concentration (5 g/100 g) using central composite design (CCD). Effectiveness of Zympex-014 towards hydrolysis of P. hermala leaves cell wall was examined by analyzing the control and enzyme-treated leave residues using scanning electron microscope (SEM). GC/MS characterization authenticated the presence of quercetin (1.44), gallic acid (0.23), caffeic acid (0.04), cinnamic acid (0.05), m-coumaric acid (0.23) and p-coumaric acid (0.37 μg/g) as the potent phenolics in Zympex-014 based extract. It can be concluded from the findings of the current work that pre-treatment of P. hermala leaves with Zympex-014 significantly enhanced the recovery of phenolics that supports its potential uses in the nutra-pharamaceutical industry.

Response Surface Methodology towards Optimization of Calotropis Procera Essential oil Extraction by using Supercritical CO2.

2019 ◽  
Vol 09 ◽  
Author(s):  
Hossein Zaeri ◽  
Bahareh Kamyab Moghadas ◽  
Bijan Honarvar ◽  
Ali Shokuhi Rad
Keyword(s):  
Response Surface Methodology ◽  
Essential Oil ◽  
Response Surface ◽  
Extraction Time ◽  
Calotropis Procera ◽  
Retrieval Rate ◽  
The Family ◽  
Effects Of Temperature ◽  
Carbon Dioxide Co2 ◽  
Central Composite

: In this research, the extraction of essential oil from Calotropis Procera with the family name of Asclepiadaceae, by supercritical carbon dioxide (CO2) solvent has been investigated in detail, and the yield and chemical profile of the extracts achieved by this method were compared with those resulted by the conventional Hydro distillation method. To optimize the process parameters of CO2 supercritical extraction (SCE) of the Calotropis Procera, the Response Surface Methodology (RSM) with central composite design (CCD) was employed. The effects of temperature, pressure, and extraction time on the oil yield are considered for investigation. Results showed that the data were sufficiently fitted into the second-order polynomial model. The extraction conditions, including pressure, temperature, and extraction time, were studied between 150-200 bar, 40-50 ºC, and 50-100 min, respectively. The optimal conditions are achieved as the temperature of 47.19ºC, the pressure of 172.2 bar, and time of 86 minutes with the retrieval rate of 31.39%.

scholarly journals Investigation of the functional network modifier loading on the stoichiometric ratio of epoxy resins and their dielectric properties

2021 ◽  
Author(s):  
Istebreq A. Saeedi ◽  
Sunny Chaudhary ◽  
Thomas Andritsch ◽  
Alun S. Vaughan
Keyword(s):  
Glass Transition ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Epoxy Resins ◽  
Functional Network ◽  
Cross Linking ◽  
Network Modifier ◽  
Epoxy Resin System ◽  
The Cross ◽  
The Impact

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

scholarly journals The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik
Keyword(s):  
Total Pore Volume ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Cross ◽  
Chain Lengths ◽  
First Time ◽  
Substituent Influence ◽  
Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

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