Electrospun Poly(Styrene-co-maleic anhydride) Nanofibers for β-D-Galactosidase Immobilization and Enzymatic Transgalactosylation

2011 ◽  
Vol 396-398 ◽  
pp. 1394-1397
Author(s):  
Peng Ju Li ◽  
Yu Fei Zhang ◽  
Song Ping Zhang ◽  
Ping Wang ◽  
Min Wang
Keyword(s):  
Maleic Anhydride ◽  
Flow Rate ◽  
Applied Voltage ◽  
Nonionic Surfactants ◽  
Immobilized Enzyme ◽  
Electrospun Nanofibers ◽  
Significant Enhancement ◽  
Enzyme Loading ◽  
Original Activity ◽  
Uniform Diameter

Poly(styrene-co-maleic anhydride) nanofibers with a uniform diameter of about 400 nm were prepared by eletrospinning a solution containing 50 % (w/v) polymer and 1% (w/v) LiCl, 25 cm gap between jection needle tip and collector, a flow rate of 200 L/h, and an applied voltage of 24 kV. β-D-galactosidase was immobilized to the electrospun nanofibers and subsequently used for synthesizing hexyl-galactoside, an important nonionic surfactants, by catalyzing the transgalactosylation reaction between hexanol and lactose. Co-electrospun LiCl was found leading to a significant enhancement in the enzyme loading and activity of the immobilized β-D-galactosidase compared to nanofiber without LiCl. After 7 reusing cycles at 37oC, the immobilized enzyme retained about 33% of its original activity.

Artificial Neural Networks Modeling of Electrospun Polyurethane Nanofibers from Chloroform/Methanol Solution

2016 ◽  
Vol 41 ◽  
pp. 18-30 ◽  
Author(s):  
Saman Firoozi ◽  
Amir Amani ◽  
Mohammad Ali Derakhshan ◽  
Hossein Ghanbari
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Polymer Solution ◽  
Flow Rate ◽  
Applied Voltage ◽  
Polymer Concentration ◽  
Electrospun Nanofibers ◽  
Dominant Factor ◽  
Artificial Neural ◽  
Chloroform Methanol

In this study, electrospun nanofibers of polyurethane were prepared utilizing a new solvent system made of chloroform/methanol. Also, we planned to assess effects of four important parameters on diameter of electrospun polyurethane nanofibers using Artificial Neural Networks (ANNs). The parameters investigated included flow rate of syringe pump, distance of spinneret to collector, applied voltage and concentration of polymer solution. Diameter of obtained electrospun nanofibers was measured using scanning electron microscopy (SEM). Results showed that flow rate and distance had reverse relation with fiber diameter, while applied voltage and concentration of polymer solution directly affected the diameter. Also, polymer concentration was shown to be the dominant factor here.

Improvement of Uniformity of Needleless Electrospun Nanofibers

2013 ◽  
Vol 821-822 ◽  
pp. 200-203
Author(s):  
Wan Jun Liu ◽  
Chen Huang ◽  
Xiang Yu Jin
Keyword(s):  
Polyvinyl Alcohol ◽  
Applied Voltage ◽  
Water Solution ◽  
Electrospun Nanofibers ◽  
Diameter Distribution ◽  
Needleless Electrospinning ◽  
Uniform Diameter

Polyvinyl alcohol (PVA) water solution was electrospun using both needle electrospinning and needleless electrospinning methods. Finer and uniform nanofibers were obtained from disc and coil electrospinng, when compared to those of conventional needle electrospinning. The finest nanofibers were 217±86 nm and 234±82 nm in diameter from disc and coil electrospinning respectively, while fibers from needle electrospinning was 296±36 nm when the applied voltage was 12kV. However, needle electrospinning produced nanofibers with a more uniform diameter distribution.

scholarly journals Production of Aspartame by Immobilized Thermolysin

2019 ◽  
pp. 1232-1239
Author(s):  
Mohammed A Alsoufi ◽  
Raghad A. Aziz
Keyword(s):  
Reaction Time ◽  
Immobilized Enzyme ◽  
Bentonite Clay ◽  
Optimum Temperature ◽  
Initial Activity ◽  
Reaction Conditions ◽  
Original Activity ◽  
Ph Profile ◽  
Full Activity ◽  
Main Activity

The aim of this study was the production of aspartame by using immobilized thermolysin in bentonite clay. The yield of immobilized thermolysin in bentonite was 92% of the original enzyme amount. pH profile of free and immobilized enzyme was 7.0 and 7.5 respectively which was stable at 6.5-9.0 for 30min. The optimum temperature of both enzymes was 50°C, while they were stable at 65°C for 30min. however, they lost 52.73 and 61.72% from its main activity at 80°C respectively. Immobilized thermolysin has retained all activity within 27 days, but it kept 68.27% of initial activity when stored for 60 days at 4°C whereas, it retained a full activity after 20 continue usage. In addition, it retained 86.53% of its original activity after 30 continuing usages. The yield of produced aspartame was increased with reaction time; it was 9% after 1h and increased gradually to 100% after 10h at reaction conditions.

EFFECT OF POLYVINYLPYRROLIDONE AND FABRICATION PARAMETERS ON ELECTROSPUN TITANIUM OXIDE NANOFIBRES’ DIAMETER

2016 ◽  
Vol 78 (12) ◽  
Author(s):  
Zi Sheng Tang ◽  
Nurmin Bolong ◽  
Ismail Saad ◽  
Rosdianah Ramli ◽  
Franklin Tiam Yang Lim
Keyword(s):  
Titanium Oxide ◽  
Flow Rate ◽  
Applied Voltage ◽  
Cost Effective ◽  
Titanium Tetraisopropoxide ◽  
Effective Technique ◽  
Polymer Carrier ◽  
Custom Made ◽  
Cost Effective Technique ◽  
Fabrication Parameters

Electrospinning is the most versatile and cost effective technique to produce titanium oxide (TiO2) nanofibres. An ethanolic solution containing titanium tetraisopropoxide, polyvinylpyrrolidone and acetic acid was loaded in the syringe to produce TiO2 nanofibres. In the present work, a custom-made electrospinning system was developed to investigate the fabrication and solution effects to the diameter of electrospun TiO2 fibres. The fabrication parameters were applied voltage (kV), flow rate (ml/hr) and tip to collector distance (cm). In addition, the effect of varying the weightage of polymer carrier on electrospun TiO2 nanofibres was investigated. The surface morphology of the fibres was examined with scanning electron microscope (SEM) and further analysed with the aid of JMicroVision. The significance of the influencing parameters was observed from high to low order as PVP content > tip to collector distance > applied voltage > flow rate. In conclusion, the parameters of applied voltage (15 kV), flow rate (1 ml/hr), tip to collector distance (10 cm) and PVP content (6 wt. %) are able to produce uniform TiO2 nanofibres.

Research on Electrospinning Process of Pullulan Nanofibers

2012 ◽  
Vol 268-270 ◽  
pp. 198-201 ◽  
Author(s):  
Xiao Bin Sun ◽  
D. Jia ◽  
Wei Min Kang ◽  
Bo Wen Cheng ◽  
Ya Bin Li
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Great Influence ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Diameter Distribution ◽  
Optimal Parameters ◽  
Redistilled Water ◽  
Water As Solvent

A kind of pullulan biopolymer nanofibers with diameter of 100～700nm were obtained using redistilled water as solvent through electrospinning technology in this paper. The effects of the spinning solution concentration, applied voltage, flow rate and capillary–screen distance on morphology and diameter distribution of pullulan nanofiber were studied by SEM. The results show that, different parameters had great influence on nanofibers’ morphology and diameter. The optimal parameters of pullulan nanofibers electrospinning were: 22wt.% spinning solution concentration, 31 kV voltage, 20 cm capillary–screen distance and 0.5ml/h flow rate.

Effect of Contaminant Flow-rate and Applied Voltage on the Current Density and Electric Field of Polymer Tracking Test

2016 ◽  
Vol 6 (2) ◽  
pp. 819
Author(s):  
F. L. Muhamedin ◽  
M. A. M. Piah ◽  
N. A. Othman ◽  
Nasir Ahmed Algeelani
Keyword(s):  
Electric Field ◽  
Flow Rate ◽  
Current Density ◽  
Applied Voltage ◽  
Fem Simulation ◽  
Surface Discharge ◽  
Physical Parameters ◽  
Insulation Material ◽  
Material Degradation ◽  
Contaminant Flow

<p>Electrical failure due to surface discharge on the insulation material will cause material degradation and eventually lead to system failure. The flow of leakage current (LC) on the insulator surface under wet contamination is used to determine the material degradation level. According to IEC 60587 standard, LC exceeding 60 mA for more than two seconds is considered as failure. In this study, the  electric field and current density distributions on the linear low-density polyethylene (LLDPE) and natural rubber blend material have been analyzed using finite element method (FEM) analysis. The physical parameters used in FEM simulation were applied with voltage and contaminant flow rate, in accordance to contaminant conductivity. Tracking test condition according to IEC 60587 standard has been applied as proposed by the reference work in simulation using QuickField FEM software. The results show that the electric field and current density would become critical in higher applied voltage and contaminant flow rate. The highest average and highest maximum current density and electric field are found in both applied voltage of 6 kV and contaminant flow rate of 0.90 mlmin<sup>-1</sup>.</p>

scholarly journals Immobilization of an Endo-β-N-acetylglucosaminidase for the Release of Bioactive N-glycans

Catalysts ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 278 ◽  
Author(s):  
Joshua Cohen ◽  
Sercan Karav ◽  
Daniela Barile ◽  
Juliana de Moura Bell
Keyword(s):  
Immobilized Enzyme ◽  
Whey Proteins ◽  
Original Activity ◽  
Kinetic Evaluation ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Pathogenic Factors ◽  
Health And Disease ◽  
Higher Temperature ◽  
Ribonuclease B

As more is learned about glycoproteins’ roles in human health and disease, the biological functionalities of N-linked glycans are becoming more relevant. Protein deglycosylation allows for the selective release of N-glycans and facilitates glycoproteomic investigation into their roles as prebiotics or anti-pathogenic factors. To increase throughput and enzyme reusability, this work evaluated several immobilization methods for an endo-β-N-acetylglucosaminidase recently discovered from the commensal Bifidobacterium infantis. Ribonuclease B was used as a model glycoprotein to compare N-glycans released by the free and immobilized enzyme. Amino-based covalent method showed the highest enzyme immobilization. Relative abundance of N-glycans and enzyme activity were determined using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Kinetic evaluation demonstrated that upon immobilization, both Vmax and the Km decreased. Optimal pH values of 5 and 7 were identified for the free and immobilized enzyme, respectively. Although a higher temperature (65 vs. 45 °C) favored rapid glycan release, the immobilized enzyme retained over 50% of its original activity after seven use cycles at 45 °C. In view of future applications in the dairy industry, we investigated the ability of this enzyme to deglycosylate whey proteins. The immobilized enzyme released a higher abundance of neutral glycans from whey proteins, while the free enzyme released more sialylated glycans, determined by nano-LC Chip Q-ToF MS.

Effect of applied voltage on jet electric current and flow rate in electrospinning of polyacrylonitrile solutions

2008 ◽  
Vol 57 (12) ◽  
pp. 1363-1368 ◽  
Author(s):  
Delaram Fallahi ◽  
Mehdi Rafizadeh ◽  
Naser Mohammadi ◽  
Behrooz Vahidi
Keyword(s):  
Electric Current ◽  
Flow Rate ◽  
Applied Voltage

The influence of geometry on the flow rate sensitivity to applied voltage within cone-jet mode electrospray

2012 ◽  
Vol 112 (11) ◽  
pp. 114510 ◽  
Author(s):  
C. N. Ryan ◽  
K. L. Smith ◽  
J. P. W. Stark
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Rate Sensitivity

Effect of Electrospinning Parameters Setting towards Fiber Diameter

2013 ◽  
Vol 845 ◽  
pp. 985-988 ◽  
Author(s):  
N.H.A. Ngadiman ◽  
M.Y. Noordin ◽  
Ani Idris ◽  
Denni Kurniawan
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Fiber Diameter ◽  
Volume Flow Rate ◽  
Electrospinning Process ◽  
Volume Flow ◽  
Fiber Volume ◽  
Nanofiber Diameter ◽  
New Process

Fabrication of nanofibers using electrospinning has recently attracted much attention for various applications due to its simplicity. Electrospinning has the ability to produce nanofibers within 100-500 nm. Some applications require certain fiber diameter. As a relatively new process, there are many electrospinning parameters that are believed to influence the nanofibers diameter. The purpose of this review is to identify and discuss the effect of some of those parameters, i.e. concentration, spinning distance, and applied voltage, and volume flow rate, to the nanofiber diameter during electrospinning process. It was concluded that fiber volume flow rate is proportional to fiber diameter while there is no agreement in reports on other parameters.

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