Facile Method of Enzyme Immobilization on Silica Quasi-Nanospheres (SiO2) Synthesized Using PODFA for Biosensing Applications

2016 ◽  
Vol 694 ◽  
pp. 67-71
Author(s):  
Nurulaina Fasya Saiful Anuar ◽  
Halina Misran ◽  
Musdalilah Ahmad Salim ◽  
S.Z. Othman
Keyword(s):  
Physical Adsorption ◽  
Glucose Sensors ◽  
Glucose Detection ◽  
Interaction Method ◽  
Bending Vibration ◽  
Support Materials ◽  
Optimum Ph ◽  
Ca 50 ◽  
Ft Ir ◽  
Absorbance Peak

In this study, silica spheres (SiO2) nanomaterials were introduced as the support materials for glucose sensors. Glucose oxidase (GOx) was immobilized onto SiO2 spheres (SiO2/GOx) using physical adsorption (electrostatic interaction) method. The SiO2 spheres were synthesized in-house using a nonsurfactant template of palm oil derived fatty alcohols (PODFA). Based on FT-IR analyses, SiO2/GOx exhibited N-H absorbance at ca. 2990 cm-1 and O-H absorbance at ca. 3330 cm-1. One new absorbance peak was observed at ca. 2320 cm1 attributed to the bending vibration (νbend)of silane molecules (Si-H) obtained by the interaction of GOx and the surface silanols (Si-OH). UV-Vis analysis results exihibited the presence of a new broad peak for GOx/SiO2 sample at ca. 250 nm to 280 nm suggested to be assigned to H2O2, C=C and benzene ring from GOx. The optimum pH and optimum temperature for SiO2/GOx for GOx activity were ca. 7.0 and ca. 50°C respectively. The increase of glucose concentration from 2mM to 5mM resulted to the increment of absorbance value for both GOx and SiO2/GOxsuggesting succesful immobilization of GOx on SiO2 spheres. These materials were suitable for glucose detection at very small glucose concentrations particularly in salivary glucose detection.

scholarly journals Enhanced Phenol Tert-Butylation Reaction Activity over Hierarchical Porous Silica-Alumina Materials

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1098
Author(s):  
Ling Xu ◽  
Fan Wang ◽  
Zhi Xiu ◽  
Limei Duan ◽  
Zongrui Liu ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Porous Silica ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
Crystallization Time ◽  
Hydrothermal Conditions ◽  
Transmission Electron ◽  
Hierarchical Porous ◽  
Silica Alumina ◽  
Ft Ir

Hierarchical aluminum-silicon materials have been successfully prepared by mixing pre-crystallization of silica-alumina sol and citric acid under hydrothermal conditions. The influence of pre-crystallization time on the micro-mesoporous structure is studied using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), N2 physical adsorption, and high-resolution transmission electron microscopy (HRTEM). The catalytic performance of hierarchical silica-alumina material is evaluated by alkylation of phenol with tert-butanol. The results show that the silica-alumina materials with a pre-crystallization time of 16 h show micro-mesoporous structure and excellent catalytic activity.

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 Adsorption of Tea Polyphenols using Microporous Starch: A Study of Kinetics, Equilibrium and Thermodynamics

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1449 ◽  
Author(s):  
Xianchun Hu ◽  
Xianfeng Du
Keyword(s):  
Physical Adsorption ◽  
Tea Polyphenols ◽  
Adsorptive Capacity ◽  
Partial Hydrolysis ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Long Term Storage ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ft Ir

Microporous starch (MPS) granules were formed by the partial hydrolysis of starch using α–amylase and glucoamylase. Due to its biodegradability and safety, MPS was employed to adsorb tea polyphenols (TPS) based on their microporous characteristics. The influences of solution pH, time, initial concentration and temperature on the adsorptive capacity were investigated. The adsorption kinetics data conformed to the pseudo second–order kinetics model, and the equilibrium adsorption data were well described by the Langmuir isotherm model. According to the fitting of the adsorption isotherm formula, the maximum adsorption capacity of TPS onto MPS at pH 6.7 and T = 293 K was approximately 63.1 mg/g. The thermodynamic parameters suggested that the adsorption of TPS onto MPS was spontaneous and exothermic. Fourier transform infrared (FT–IR) analysis and the thermodynamics data were consistent with a physical adsorption mechanism. In addition, MPS-loaded TPS had better stability during long-term storage at ambient temperature.

Investigation of the Hydrophobization Efficiency of Terbium-Exchanged BEA Zeolites by Means of FT-IR, TGA, Physical Adsorption, and Time-Resolved Photoluminescence

Langmuir ◽  
2007 ◽  
Vol 23 (12) ◽  
pp. 6781-6787 ◽  
Author(s):  
Carmen Tiseanu ◽  
Bogdan Gagea ◽  
Vasile Ion Parvulescu ◽  
Víctor Lórenz-Fonfría ◽  
André Gessner ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Time Resolved ◽  
Ft Ir ◽  
Time Resolved Photoluminescence

Study on Adsorption Characteristics of Klebsiella Biological Adsorbent to Leaded Wastewater

2014 ◽  
Vol 926-930 ◽  
pp. 4353-4356
Author(s):  
Jing Zhao ◽  
Xiao Jun Xu ◽  
Qiang Zhan ◽  
Xuan Li ◽  
Shu Li Liu ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Adsorption Properties ◽  
Amide Group ◽  
Langmuir Isotherm Model ◽  
Ft Ir ◽  
Resistant Strains ◽  
Main Component

A lead-resistant strains was isolated from activated sludge of the sewage treatment plant in Chenggong County, Kunming, which was identified as Klebsiella by 16 SrDNA. The wet microbial cells were used as adsorbent, we studied adsorption properties for water Pb (II) ions in water of sorbent. The results showed that when the adsorbent treated the waste water with Pb (II) ions, the pH was 5, the time was 60min, the temperature was 30°C, the equilibrium adsorption amount was 73.45mg/g; Adsorbent’s adsorption of Pb (II) ions can better fit Langmuir isotherm model. The FT-IR result presented that the main component of adsorbent was polysaccharide, the physical adsorption and chemisorption occurred between the adsorbent and the Pb (II) ions in the solution, adsorption mainly involved with hydroxyl functional groups, the amide group and the carboxyl group, etc.

Spectroscopic Investigations on the Depth-Dependent Degradation Gradients of Aged Triterpenoid Varnishes

2007 ◽  
Vol 61 (10) ◽  
pp. 1045-1051 ◽  
Author(s):  
Charis Theodorakopoulos ◽  
Vassilis Zafiropulos ◽  
Jaap J. Boon ◽  
Stamatis C. Boyatzis
Keyword(s):  
Structural Modification ◽  
Attenuated Total Reflection ◽  
Vibration Modes ◽  
Bending Vibration ◽  
Depth Profiles ◽  
Excimer Laser Ablation ◽  
Natural Resin ◽  
Ft Ir ◽  
Krf Excimer Laser ◽  
Ft Ir Spectroscopy

The depth-profiles of accelerated aged triterpenoid dammar and mastic varnishes, which had been uncovered by optimized KrF excimer laser ablation (248 nm, 25 ns), were examined by ultraviolet–visible (UV/VIS) spectrophotometry and attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy. The results reflect both the optical properties at the bulk (UV/VIS) and the surface (ATR/FT-IR) and establish the presence of degradation gradients across the depth of the degraded natural resin films. It is demonstrated that the UV part of the ambient radiation is absorbed by the deteriorated surface and that the optical densities of the aged varnish decrease as a function of depth. The absorbed UV wavelengths at the surface and the depth-wise reduction of light intensity result in a depth-dependent decrease in carbonyl absorbance and an increase in C–H bending vibration modes of methylene species pointing to structural modification in the triterpenoid mixture across depth.

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 Isolation of Lycopene Component from Tamarillo (Solanum betaceum)

2021 ◽  
Vol 9 (2) ◽  
pp. 99-104
Author(s):  
Jeanne Dewi Damayanti ◽  
Ririn Azmilia ◽  
Zul Ainun ◽  
Nur Amin R. ◽  
M. Ilham Nurdin
Keyword(s):  
Group Analysis ◽  
Extraction Process ◽  
Premature Aging ◽  
Gas Chromatography Mass Spectrometry ◽  
Negative Effects ◽  
Bending Vibration ◽  
Ft Ir ◽  
Functional Group Analysis ◽  
Fruit Powder

Lycopene is a red pigment found in tamarillo with its function as an antioxidant that protects body cells from the negative effects of free radicals so that they do not trigger diseases, especially cancer and premature aging. This study was intended to improve the quality of tamarillo by isolating lycopene from tamarillo through an extraction process with chloroform as a solvent by maceration for 3 days at room temperature. The lycopene extract obtained was dissolved by means of a rotary evaporator at 40 oC under vacuum pressure and oven temperature at 60 oC. The lycopene obtained was analyzed by Gas Chromatography-Mass Spectrometry and the crystal structure of lycopene was characterized by Fourier Transform Infra-Red Spectroscopy. GCMS results showed that 0.21 g of lycopene was successfully isolated from 100 g of dried red tamarillo fruit powder. Functional group analysis using FT-IR at a wavelength of 978.23 cm-1 showed the R-CH=CH-R group; the -CH3- group of 1371.43 cm-1; the 1460.16 cm-1 indicates the bending vibration of -CH2-; the C=C chain of 1656.91 and 1745.64 cm-1; and the   C-H of 2856.67 and 2926.11 cm-1 of the lycopene chain.

scholarly journals Recent Advances in Non-Enzymatic Glucose Sensors Based on Metal and Metal Oxide Nanostructures for Diabetes Management- A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Gowhar A. Naikoo ◽  
Hiba Salim ◽  
Israr U. Hassan ◽  
Tasbiha Awan ◽  
Fareeha Arshad ◽  
...  
Keyword(s):  
Active Sites ◽  
Glucose Oxidation ◽  
Diabetes Management ◽  
Glucose Sensing ◽  
Glucose Sensors ◽  
Glucose Detection ◽  
Hydrous Oxide ◽  
Oxide Nanostructures ◽  
Metal Oxide Nanostructures ◽  
Glucose Electrooxidation

There is an undeniable growing number of diabetes cases worldwide that have received widespread global attention by many pharmaceutical and clinical industries to develop better functioning glucose sensing devices. This has called for an unprecedented demand to develop highly efficient, stable, selective, and sensitive non-enzymatic glucose sensors (NEGS). Interestingly, many novel materials have shown the promising potential of directly detecting glucose in the blood and fluids. This review exclusively encompasses the electrochemical detection of glucose and its mechanism based on various metal-based materials such as cobalt (Co), nickel (Ni), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), titanium (Ti), iridium (Ir), and rhodium (Rh). Multiple aspects of these metals and their oxides were explored vis-à-vis their performance in glucose detection. The direct glucose oxidation via metallic redox centres is explained by the chemisorption model and the incipient hydrous oxide/adatom mediator (IHOAM) model. The glucose electrooxidation reactions on the electrode surface were elucidated by equations. Furthermore, it was explored that an effective detection of glucose depends on the aspect ratio, surface morphology, active sites, structures, and catalytic activity of nanomaterials, which plays an indispensable role in designing efficient NEGS. The challenges and possible solutions for advancing NEGS have been summarized.

scholarly journals Characterisation of a “green” lipase from Aspergillus niger immobilised on polyethersulfone membranes

2019 ◽  
Vol 42 ◽  
pp. e44498
Author(s):  
Fernanda Martins de Souza ◽  
Cleide Mara Faria Soares ◽  
Alvaro Silva Lima ◽  
Luciana Cristina Lins de Aquino Santana
Keyword(s):  
Thermal Stability ◽  
Aspergillus Niger ◽  
Thermal Inactivation ◽  
Physical Adsorption ◽  
Covalent Bonding ◽  
Point Of View ◽  
Thermal Stabilities ◽  
Optimum Ph ◽  
Hancornia Speciosa ◽  
Free Lipase

In this work, a “green” Aspergillus niger lipase obtained from the solid-state fermentation of Hancornia speciosa (“mangaba”) seeds was efficiently immobilised on polyethersulfone membranes (PES) by physical adsorption (PES-ADS-lipase) and covalent bonding (PES-COV-lipase) (immobilisation yields of 92 and 81%, respectively). The free lipase showed an optimum pH close to neutrality, while the biocatalysts displaced the pH to the alkaline region (optimum pH 9.0 and 11.0 for PES-ADS-lipase and PES-COV-lipase, respectively). The optimum temperature of free lipase was 55°C; however, a higher thermal stability occurred at 37°C. The PES-ADS-lipase and PES-COV-lipase showed lower optimum temperatures (37 and 45°C, respectively) but higher thermal stabilities at 45 and 55°C, respectively. The lower thermal inactivation constant and higher half-life of PES-COV-lipase at 55°C confirmed the efficiency of covalent bonding in maintaining the thermal stability of the enzyme. The Michaelis–Menten constant (Km) and maximum rate of reaction (Vmax) were also determined, and the biocatalysts showed higher affinities to substrates (lower Km values) than free lipase. In this work, the biocatalysts showed good catalytic properties with future potential applications in hydrolysis reactions. The use of a “green” lipase obtained from agroindustrial residue makes this product economically attractive from an industrial point of view.

Sign in / Sign up

Export Citation Format

Share Document