scholarly journals Effect of parameters on butyl butyrate synthesis using novel Aspergillus niger lipase as biocatalyst

2018 ◽  
Vol 40 (1) ◽  
pp. 35999 ◽  
Author(s):  
Beatriz Medeiros Travalia ◽  
Mercia Galvão ◽  
Alvaro Silva Lima ◽  
Cleide Mara Faria Soares ◽  
Narendra Narain ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Sol Gel ◽  
Molar Ratio ◽  
Free Form ◽  
Butyl Butyrate ◽  
Pumpkin Seeds ◽  
Higher Temperature ◽  
Substrate Molar Ratio ◽  
Esterification Reactions ◽  
Butyrate Production

 A novel “green” Aspergillus niger lipase, obtained from the fermentation of pumpkin seeds, was used in a free form and encapsulated in sol-gel matri x in butyl butyrate (pineapple flavor) synthesis. Esterification reactions were performed with varying substrate molar ratio (butanol: butyric acid) ranging between 1:1 and 5:1; temperature between 30 and 60°C and biocatalyst mass between 0 and 1g, respectively, according to experimental design 23 with 6 axial and 3 central points. Maximum butyl butyrate production was obtained when substrate molar ratio (butanol:butyric acid) 3:1, temperature at 60°C and 0.5 g free or encapsulated lipase as biocatalyst, were used. Temperature was the most significant parameter for production with the two biocatalysts, indicating that higher rates mean greater compound synthesis. Response surface plots showed that higher butyl butyrate production may be obtained with higher temperature and molar ratio rates (butanol:butyric acid) and with lower rates of biocatalyst mass in reactions catalyzed by free or encapsulated lipase. Aspergillus niger lipase obtained from agro-industrial waste could be employed as biocatalyst in esterification reactions in the production of natural aroma as butyl butyrate.  

Morphology and Phase Composition of Sol-Gel Derived Aluminum Borate Nanowhiskers

2015 ◽  
Vol 659 ◽  
pp. 121-126 ◽  
Author(s):  
Pat Sooksaen
Keyword(s):  
Fourier Transform ◽  
Phase Composition ◽  
Sol Gel ◽  
Molar Ratio ◽  
Aluminum Borate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature ◽  
Sol Gel Synthesis ◽  
Scanning Electron

Aluminium borate nanowhiskers with varying aspect ratio were synthesized via sol–gel synthesis. The morphology of aluminum borate (Al4B2O9 and Al18B4O33) nanowhiskers could be controlled by varying the aluminum to boron (Al:B) molar ratio in the sol–gel derived precursors. Sintering temperatures (850 and 1100°C) and sintering times (4 and 32 hours) also affected the phase composition and size of the nanowhiskers. Citric acid was also added in the sol–gel derived precursors as a surface stabilizer for obtaining uniform finely dispersed nanostructures. Fine nanowhiskers were obtained by the calcination at 850°C, whereas higher temperature of 1100°C led to thicker and longer nanowhiskers and became rod-like crystals. The morphology and phase composition were investigated by field emission scanning electron microscope and X-ray diffraction. Chemical bond vibrations in the synthesized nanowhiskers were investigated by Fourier-transform infrared spectroscopy.

scholarly journals Influence of molar ratio on dielectric, ferroelectric and magnetic properties of Co0.5Mg0.5Fe2O4/Ba0.85Sr0.15TiO3 composite ceramics

2019 ◽  
Vol 13 (3) ◽  
pp. 257-268
Author(s):  
Lang Bai ◽  
Rongli Gao ◽  
Qingmei Zhang ◽  
Zhiyi Xu ◽  
Zhenhua Wang ◽  
...  
Keyword(s):  
Sol Gel ◽  
Peak Position ◽  
Relaxation Peak ◽  
Molar Ratio ◽  
Composite Ceramics ◽  
Molar Ratios ◽  
Mean Grain Size ◽  
Higher Temperature ◽  
Two Phases ◽  
Two Peaks

In the present work, Co0.5Mg0.5Fe2O4/Ba0.85Sr0.15TiO3 (CMFO/BST) composite ceramics with different molar ratios (1:1, 1:2, 1:4, 1:6 and 1:8) were prepared by sol-gel method and sintered at 1150?C. The effects of molar ratio on the structure, dielectric and multiferroic properties were comparatively studied. The results indicate that all the synthesized composites mainly show bi-phase structure except slight presence of impurity phases. The surface of the specimens is relatively dense and the mean grain size is about 2 ?m. It decreases at first and then increases with the increased molar ratio. The dielectric constant shows decreased trend with increasing the molar ratio, while the dielectric loss presents the opposite behaviour. With the increase of molar ratio, the height of the relaxation peak decreases while the peak position shifts to higher temperature range. The relaxation peak evolves gradually from one to two peaks. The residual polarization increases with voltage but decreases with frequency. The maximal polarization of 1.28 ?C/cm2 is obtained in the specimen with the molar ratio of 1:8, due to the largest concentration of ferroelectric phase BST. The magnetization shows abnormal behaviour with the change in molar ratio. The largest saturation and remnant magnetization are 20.89 and 12.66 emu/g, respectively when the molar ratio is 1:2 due to the stronger interface interaction effect between the two phases.

scholarly journals Immobilization of Naringinase from Aspergillus Niger on a Magnetic Polysaccharide Carrier

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2731 ◽  
Author(s):  
Joanna Bodakowska-Boczniewicz ◽  
Zbigniew Garncarek
Keyword(s):  
Activation Energy ◽  
Aspergillus Niger ◽  
Free Form ◽  
Magnetic Carrier ◽  
Binding Force ◽  
Application Potential ◽  
Pharmaceutical Industries ◽  
Higher Temperature ◽  
Deactivation Process ◽  
Catalytic Capacity

Naringinase is an enzymatic complex used in the deglycosylation of compounds with a high application potential in the food and pharmaceutical industries. The aim of the study was to immobilize naringinase from Aspergillus niger KMS on a magnetic carrier obtained on the basis of carob gum activated by polyethyleneimine. Response surface methodology was used to optimize naringinase immobilization taking into account the following factors: pH, immobilization time, initial concentration of naringinase and immobilization temperature. The adsorption of the enzyme on a magnetic carrier was a reversible process. The binding force of naringinase was increased by crosslinking the enzyme with the carrier using dextran aldehyde. The crosslinked enzyme had better stability in an acidic environment and at a higher temperature compared to the free form. The immobilization and stabilization of naringinase by dextran aldehyde on the magnetic polysaccharide carrier lowered the activation energy, thus increasing the catalytic capacity of the investigated enzyme and increasing the activation energy of the thermal deactivation process, which confirms higher stability of the immobilized enzyme in comparison with free naringinase. The preparation of crosslinked naringinase retained over 80% of its initial activity after 10 runs of naringin hydrolysis from fresh and model grapefruit juice.

scholarly journals Enzymatic Production of Bio-Diesel from Waste Cooking Oil Using Lipase

2008 ◽  
Vol 2 (1) ◽  
pp. 84-88 ◽  
Author(s):  
Sulaiman Al-Zuhair
Keyword(s):  
Immobilized Lipase ◽  
Sol Gel ◽  
Waste Cooking Oil ◽  
Molar Ratio ◽  
Free Form ◽  
Kinetics Parameters ◽  
Enzymatic Production ◽  
Cooking Oil ◽  
Free Lipase

The applications of lipase immobilized on ceramic beads and entrapped in sol-gel matrix, in the production of bio-diesel from waste cooking oil, are compared to that of free lipase. Experimental determination of the effect of molar equivalent of methanol, to moles of ester bond in the triglyceride, on the rate of the enzymatic trans-esterification was experimentally determined. It was found that for the same weight of lipase used, the production of bio-diesel was much higher using lipase immobilized on ceramic beads in comparison to that using lipase entrapped in sol-gel and in free form. Substrates inhibition effect was observed in all cases, which agrees with previous results found in literature. The optimum methanol:oil molar ratio was found to be 0.87 for immobilized lipase from yeast source, C. antartica and 1.00 for free lipase from the same yeast source and immobilized lipase from bacterial source, P. cepacia. On the other hand, it was shown that biodieasel can be produced in considerable amounts, with yield reaching 40%, in absence of organic solvent using immobilized lipase, from P. cepacia, on ceramic beads. The results of this study can be used to determine the kinetics parameters of mathematical models which describe the system.

scholarly journals Influence of Synthesis Variables on the Textural Properties of Mesoporous Carbon Xerogels

2016 ◽  
Vol 2 (4) ◽  
Author(s):  
Nagendranath Mahata ◽  
Kamala Mandy Hansda ◽  
Gorachand Neogi ◽  
Nihar Ranjan Mahato
Keyword(s):  
Mesoporous Carbon ◽  
Sol Gel ◽  
Textural Properties ◽  
Molar Ratio ◽  
Carbon Xerogel ◽  
Carbon Xerogels ◽  
Higher Temperature ◽  
Subcritical Drying ◽  
Gel Processing ◽  
Organic Gel

Influence of synthesis variables on the textural properties of mesoporous carbon xerogels is studied. Variables explored in synthesizing mesoporous carbon xerogels (CX) are: (i) initial formaldehyde/resorcinol molar ratio in preparing the sol, (ii) pH of sol-gel processing, (iii) temperature of gelling and subsequent curing of the gel, and (iv) mode of subcritical drying of the wet gel. Making of sol having formaldehyde/resorcinol molar ratio little higher than 2 and sol-gel processing at pH around 6 resulted in carbon xerogel with wide pores. Curing of gel at higher temperature resulted in carbon xerogel with narrower pores. Drying of the organic gel after exchanging water with low boiling organic solvent was highly beneficial in obtaining carbon xerogel with wider pores along with larger mesoporous area.

Efficient Micromixing for Continuous Biodiesel Production from Jatropha Oil

2018 ◽  
Vol 9 (1) ◽  
pp. 133-139
Author(s):  
Waleed S. Mohammed ◽  
Ahmed H. El-Shazly ◽  
Marwa F. Elkady ◽  
Masahiro Ohshima
Keyword(s):  
Methyl Esters ◽  
Continuous Process ◽  
Sol Gel ◽  
Average Diameter ◽  
Biodiesel Production ◽  
High Mass ◽  
Molar Ratio ◽  
Jatropha Oil ◽  
Energy Deficiency ◽  
Gel Preparation

Introduction: The utilization of biodiesel as an alternative fuel is turning out to be progressively famous these days because of worldwide energy deficiency. The enthusiasm for utilizing Jatropha as a non-edible oil feedstock is quickly developing. The performance of the base catalyzed methanolysis reaction could be improved by a continuous process through a microreactor in view of the high mass transfer coefficient of this technique. Materials & Methods: Nanozirconium tungstovanadate, which was synthetized using sol-gel preparation method, was utilized in a complementary step for biodiesel production process. The prepared material has an average diameter of 0.066 &µm. Results: First, the NaOH catalyzed methanolysis of Jatropha oil was investigated in a continuous microreactor, and the efficient mixing over different mixers and its impact on the biodiesel yield were studied under varied conditions. Second, the effect of adding the nanocatalyst as a second stage was investigated. Conclusion: The maximum percentage of produced methyl esters from Jatropha oil was 98.1% using a methanol/Jatropha oil molar ratio of 11 within 94 s using 1% NaOH at 60 &°C. The same maximum conversion ratio was recorded with the nanocatalyst via only 0.3% NaOH.

scholarly journals One-step synthesis of nitrogen-grafted copper-gallic acid for enhanced methylene blue removal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shella Permatasari Santoso ◽  
Vania Bundjaja ◽  
Artik Elisa Angkawijaya ◽  
Chintya Gunarto ◽  
Alchris Woo Go ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Gallic Acid ◽  
Synthesis Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
One Step ◽  
Detailed Assessment ◽  
Higher Temperature

AbstractNitrogen-grafting through the addition of glycine (Gly) was performed on a metal- phenolic network (MPN) of copper (Cu2+) and gallic acid (GA) to increase its adsorption capacity. Herein, we reported a one-step synthesis method of MPN, which was developed according to the metal–ligand complexation principle. The nitrogen grafted CuGA (Ng-CuGA) MPN was obtained by reacting Cu2+, GA, and Gly in an aqueous solution at a molar ratio of 1:1:1 and a pH of 8. Several physicochemical measurements, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), N2 sorption, X-ray diffraction (XRD), and thermal gravimetry analysis (TGA), were done on Ng-CuGA to elucidate its characteristics. The analysis revealed that the Ng-CuGA has non-uniform spherical shaped morphology with a pore volume of 0.56 cc/g, a pore size of 23.25 nm, and thermal stability up to 205 °C. The applicational potential of the Ng-CuGA was determined based on its adsorption capacity against methylene blue (MB). The Ng-CuGA was able to adsorb 190.81 mg MB per g adsorbent at a pH of 6 and temperature of 30 °C, which is 1.53 times higher than the non-grafted CuGA. Detailed assessment of Ng-CuGA adsorption properties revealed their pH- and temperature-dependent nature. The adsorption capacity and affinity were found to decrease at a higher temperature, demonstrating the exothermic adsorption behavior.

scholarly journals Green Synthesis of N/Zr Co-Doped TiO2 for Photocatalytic Degradation of p-Nitrophenol in Wastewater

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 235
Author(s):  
Hayette Benkhennouche-Bouchene ◽  
Julien G. Mahy ◽  
Cédric Wolfs ◽  
Bénédicte Vertruyen ◽  
Dirk Poelman ◽  
...  
Keyword(s):  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Sol Gel ◽  
Visible Region ◽  
Chemical Properties ◽  
Pure Tio2 ◽  
Molar Ratio ◽  
Xps Spectra ◽  
Doped Tio2 ◽  
Co Doped

TiO2 prepared by a green aqueous sol–gel peptization process is co-doped with nitrogen and zirconium to improve and extend its photoactivity to the visible region. Two nitrogen precursors are used: urea and triethylamine; zirconium (IV) tert-butoxide is added as a source of zirconia. The N/Ti molar ratio is fixed regardless of the chosen nitrogen precursor while the quantity of zirconia is set to 0.7, 1.4, 2, or 2.8 mol%. The performance and physico-chemical properties of these materials are compared with the commercial Evonik P25 photocatalyst. For all doped and co-doped samples, TiO2 nanoparticles of 4 to 8 nm of size are formed of anatase-brookite phases, with a specific surface area between 125 and 280 m2 g−1 vs. 50 m2 g−1 for the commercial P25 photocatalyst. X-ray photoelectron (XPS) measurements show that nitrogen is incorporated into the TiO2 materials through Ti-O-N bonds allowing light absorption in the visible region. The XPS spectra of the Zr-(co)doped powders show the presence of TiO2-ZrO2 mixed oxide materials. Under visible light, the best co-doped sample gives a degradation of p-nitrophenol (PNP) equal to 70% instead of 25% with pure TiO2 and 10% with P25 under the same conditions. Similarly, the photocatalytic activity improved under UV/visible reaching 95% with the best sample compared to 50% with pure TiO2. This study suggests that N/Zr co-doped TiO2 nanoparticles can be produced in a safe and energy-efficient way while being markedly more active than state-of-the-art photocatalytic materials under visible light.

Sol-Gel Synthesis and Characterization of Ultrafine ZrSiO4 Powder

2014 ◽  
Vol 906 ◽  
pp. 66-71
Author(s):  
Zhen Quan Li ◽  
Qiang Zhen ◽  
Ya Li Wang
Keyword(s):  
Wavelength Range ◽  
High Purity ◽  
Raw Materials ◽  
Formation Rate ◽  
Sol Gel ◽  
Molar Ratio ◽  
Sem And Tem ◽  
Homogeneous Product ◽  
Sol Gel Synthesis ◽  
Calcined Temperature

High purity ZrSiO4 powder were synthesized using Si (C2H5O)4 and ZrOCl2·8H2O as raw materials by the sol-gel method, LiCl was added as mineralizer to promote crystallization of zircon. The influences of molar ratio of Zr:Si, calcined time and calcined temperature on the synthesis of ZrSiO4 powder were investigated. XRD, SEM and TEM were used to characterize the powders. It was found that when the molar ratio of Zr:Si was 1:1.2, the calcined temperature was 1600°C and the calcined time was 4h, the high purity ZrSiO4 ultrafine powder was obtained. The ZrSiO4 formation began at 1300°C and when the gel was calcined at 1600°Cfor 4 h, the formation rate of ZrSiO4 was up to 95%. SEM and TEM studies reveal a homogeneous product with particle sizes on the order of 0.1-1μm. The IR emissivity of ultrafine ZrSiO4 is 0.892 at the whole wavelength range, and that is up to 0.951 at the wavelength range of 8-14 μm.

scholarly journals Continuous Production of Lipase-Catalyzed Biodiesel in a Packed-Bed Reactor: Optimization and Enzyme Reuse Study

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Hsiao-Ching Chen ◽  
Hen-Yi Ju ◽  
Tsung-Ta Wu ◽  
Yung-Chuan Liu ◽  
Chih-Chen Lee ◽  
...  
Keyword(s):  
Flow Rate ◽  
Immobilized Lipase ◽  
Continuous Production ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Molar Ratio ◽  
System Response ◽  
Biodiesel Synthesis ◽  
Substrate Molar Ratio ◽  
Molar Conversion

An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435) as a catalyst in atert-butanol solvent system. Response surface methodology (RSM) and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature52.1∘C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were83.31±2.07% and82.81±.98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis.

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