scholarly journals Efficient Biodiesel Production Catalyzed by Nanobioconjugate of Lipase from Pseudomonas fluorescens

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 651 ◽  
Author(s):  
Judith-Hajnal Bartha-Vári ◽  
Mădălina Elena Moisă ◽  
László Csaba Bencze ◽  
Florin-Dan Irimie ◽  
Csaba Paizs ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Carbon Nanomaterials ◽  
Diglycidyl Ether ◽  
Biodiesel Production ◽  
Optimal Conditions ◽  
Initial Activity ◽  
Batch System ◽  
Multiple Recycling ◽  
Walled Carbon Nanotubes ◽  
Active Lipase

The Amano lipase from Pseudomonas fluorescens (L-AK) was covalently immobilized on various carbon nanomaterials (functionalized single-walled carbon nanotubes and graphene oxide) and tested for biodiesel production. Using the most active lipase preparation (covalently immobilized L-AK on SwCNTNH2 derivatized with glycerol diglycidyl ether) under optimal conditions, quasi-complete conversion (>99%) of sunflower oil was obtained after only 4 h reaction time. Moreover, the biocatalyst maintained more than 99% of its initial activity in the batch system after multiple recycling experiments.

scholarly journals Preparation of Bulk13C-Enriched Graphene Materials

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Leilei Tian ◽  
Xin Wang ◽  
Li Cao ◽  
Mohammed J. Meziani ◽  
Chang Yi Kong ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Convenient Method ◽  
Carbon Nanomaterials ◽  
Arc Discharge ◽  
Single Walled Carbon Nanotubes ◽  
Production Technique ◽  
Graphene Oxides ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes ◽  
Bulk Production

Arc-discharge has been widely used in the bulk production of various carbon nanomaterials, especially for structurally more robust single-walled carbon nanotubes. In this paper, the same bulk-production technique was applied to the synthesis of significantly13C-enriched graphitic materials, from which graphene oxides similarly enriched with13C were prepared and characterized. The results demonstrate that arc-discharge is a convenient method to produce bulk quantities of13C-enriched graphene materials from relatively less expensive precursors (largely amorphous13C powders).

scholarly journals Expression and Characterization of a Dye-Decolorizing Peroxidase from Pseudomonas Fluorescens Pf0-1

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 463 ◽  
Author(s):  
Nikola Lončar ◽  
Natalija Drašković ◽  
Nataša Božić ◽  
Elvira Romero ◽  
Stefan Simić ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pseudomonas Fluorescens ◽  
Alginate Beads ◽  
Sequence Information ◽  
Soluble Enzyme ◽  
Initial Activity ◽  
Alternative Substrate ◽  
65 H ◽  
Genome Sequence Information

The consumption of dyes is increasing worldwide in line with the increase of population and demand for clothes and other colored products. However, the efficiency of dyeing processes is still poor and results in large amounts of colored effluents. It is desired to develop a portfolio of enzymes which can be used for the treatment of colored wastewaters. Herein, we used genome sequence information to discover a dye-decolorizing peroxidase (DyP) from Pseudomonas fluorescens Pf-01. Two genes putatively encoding for DyPs were identified in the respective genome and cloned for expression in Escherichia coli, of which one (PfDyP B2) could be overexpressed as a soluble protein. PfDyP B2 shows some typical features known for DyPs which includes the ability to convert dyes at the expense of hydrogen peroxide. Interestingly, t-butyl hydroperoxide could be used as an alternative substrate to hydrogen peroxide. Immobilization of PfDyP B2 in calcium-alginate beads resulted in a significant increase in stability: PfDyP B2 retains 80% of its initial activity after 2 h incubation at 50 °C, while the soluble enzyme is inactivated within minutes. PfDyP B2 was also tested with aniline and ethyl diazoacetate as substrates. Based on GC-MS analyses, 30% conversion of the starting material was achieved after 65 h at 30 °C. Importantly, this is the first report of a DyP-catalyzed insertion of a carbene into an N-H bond.

Electrical and piezoresistive properties of cement composites with carbon nanomaterials

2018 ◽  
Vol 52 (24) ◽  
pp. 3325-3340 ◽  
Author(s):  
Doo-Yeol Yoo ◽  
Ilhwan You ◽  
Hyunchul Youn ◽  
Seung-Jung Lee
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Carbon Nanomaterials ◽  
Peak Load ◽  
Compressive Load ◽  
Gauge Factor ◽  
Fractional Change ◽  
Graphite Nanofibers ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

This study investigates the effect of nanomaterials on the piezoresistive sensing capacity of cement-based composites. Three different nanomaterials—multi-walled carbon nanotubes, graphite nanofibers, and graphene oxide—were considered along with a plain mortar, and a cyclic compressive test was performed. Based on a preliminary test, the optimum flowability was determined to be 150 mm in terms of fiber dispersion. The electrical resistivity of the composites substantially decreased by incorporating 1 wt% multi-walled carbon nanotubes, but only slightly decreased by including 1 wt% graphite nanofibers and graphene oxide. This indicates that the use of multi-walled carbon nanotubes is most effective in improving the conductivity of the composites compared to the use of graphite nanofibers and graphene oxide. The fractional change in resistivity of the composites with nanomaterials exhibited similar behavior to that of the cyclic compressive load, but partial reversibility in fractional change in resistivity was obtained beyond 60% of the peak load. A linear relationship between the fractional change in resistivity and cyclic compression strain (up to 1500 με) was observed in the composites with multi-walled carbon nanotubes, and the gauge factor was found to be 166.6. It is concluded that cement-based composites with 1 wt% multi-walled carbon nanotubes can be used as piezoresistive sensors for monitoring the stress/strain generated in concrete structures.

scholarly journals Reuse of Lipase from Pseudomonas fluorescens via Its Step-by-Step Coimmobilization on Glyoxyl-Octyl Agarose Beads with Least Stable Lipases

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 487 ◽  
Author(s):  
Nathalia Rios ◽  
Sara Arana-Peña ◽  
Carmen Mendez-Sanchez ◽  
Claudia Ortiz ◽  
Luciana Gonçalves ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Rhizomucor Miehei ◽  
The Other ◽  
Initial Activity ◽  
Interfacial Activation ◽  
Full Activity ◽  
Agarose Beads ◽  
Lecitase Ultra ◽  
The Stability ◽  
Triton X

Coimmobilization of lipases may be interesting in many uses, but this means that the stability of the least stable enzyme determines the stability of the full combilipase. Here, we propose a strategy that permits the reuse the most stable enzyme. Lecitase Ultra (LU) (a phospholipase) and the lipases from Rhizomucor miehei (RML) and from Pseudomonas fluorescens (PFL) were immobilized on octyl agarose, and their stabilities were studied under a broad range of conditions. Immobilized PFL was found to be the most stable enzyme under all condition ranges studied. Furthermore, in many cases it maintained full activity, while the other enzymes lost more than 50% of their initial activity. To coimmobilize these enzymes without discarding fully active PFL when LU or RML had been inactivated, PFL was covalently immobilized on glyoxyl-agarose beads. After biocatalysts reduction, the other enzyme was coimmobilized just by interfacial activation. After checking that glyoxyl-octyl-PFL was stable in 4% Triton X-100, the biocatalysts of PFL coimmobilized with LU or RML were submitted to inactivation under different conditions. Then, the inactivated least stable coimmobilized enzyme was desorbed (using 4% detergent) and a new enzyme reloading (using in some instances RML and in some others employing LU) was performed. The initial activity of immobilized PFL was maintained intact for several of these cycles. This shows the great potential of this lipase coimmobilization strategy.

scholarly journals Load Sensing Capability of Cementitious Matrixes—Nanomodified Cement Versus Carbon Nanotube Dispersion

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 19
Author(s):  
Buasiri ◽  
Habermehl-Cwirzen ◽  
Krzeminski ◽  
Cwirzen
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Carbon Nanomaterials ◽  
Compressive Load ◽  
Weight Changes ◽  
Load Sensing ◽  
Carbon Nanotube Dispersion ◽  
Uniform Dispersion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A cement-based matrix incorporating conductive materials such as carbon nanotubes and carbon nanofibers can have self-sensing capability. Both nanomaterials are characterized by excellent physical, mechanical and electrical properties. A disadvantage is that due to their hydrophobic nature it is very difficult to ensure uniform dispersion throughout the cementitious matrix. To overcome this problem a new nanomodified cement containing in-situ attached CNFs was developed leading to a very homogenous and conductive binder matrix. This study aimed to compare the piezoresistive responses of two types of matrixes, one based on the nanomodified cement and the second containing multi-walled carbon nanotubes. Several mortars were prepared containing either MWCNTs or the nanomodified cement, which partially replaced the untreated cement. The effective amount of the carbon nanomaterials was the same for both types of mixes and ranged from 0 wt.% to 0.271 wt.%, calculated by the all binder weight. Changes in the electrical properties were determined while applying compressive load. The results showed that the binders based on the nanomodified cement have significantly better load sensing capabilities and are suitable for applications in monitoring systems.

scholarly journals Sulfonated multi-walled carbon nanotubes for biodiesel production through triglycerides transesterification

RSC Advances ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 7250-7258 ◽  
Author(s):  
Qingqing Guan ◽  
Yi Li ◽  
Yuan Chen ◽  
Yuzhen Shi ◽  
Junjie Gu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Solid Acid ◽  
Biodiesel Production ◽  
Solid Acid Catalysts ◽  
Acid Catalysts ◽  
High Quality ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Effective solid acid catalysts play a key role to produce high-quality biodiesel through triglyceride transesterification.

scholarly journals Epoxy-based nanocomposites with amine modified single walled carbon nanotubes

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Celina-Maria Petrea ◽  
Corina Andronescu ◽  
Andreea Madalina Pandele ◽  
Sorina Alexandra Garea ◽  
Horia Iovu
Keyword(s):  
Carbon Nanotubes ◽  
Single Walled Carbon Nanotubes ◽  
Diglycidyl Ether ◽  
Covalent Attachment ◽  
Single Walled Carbon ◽  
Reinforcing Agent ◽  
Different Types ◽  
Walled Carbon Nanotubes ◽  
Thermal Stability Of ◽  
Long Chain

AbstractCarboxylated Single Walled Carbon Nanotubes (SWNT-COOH) were functionalized using different types of amines as modifier agents to improve the compatibility with the epoxy matrix. Covalent attachment was proved by XPS and Raman spectroscopy. TGA showed that only long chain modifier agents improved the thermal stability of modified SWNTs. Epoxy-based composites were synthesized using diglycidyl ether of bisphenol A (DGEBA) as polymer matrix and modified SWNTs as reinforcing agent.

Optimized Enzymatic Production of Waste Oil to Biodiesel

2013 ◽  
Vol 291-294 ◽  
pp. 284-289
Author(s):  
Xue Lin Zhang ◽  
Jun Jun Li ◽  
Xiang Hua Tang ◽  
Zhen Rong Xie ◽  
Zun Xi Huang
Keyword(s):  
Response Surface Methodology ◽  
Experimental Designs ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
Optimum Conditions ◽  
Waste Oil ◽  
Reaction Parameters ◽  
Enzymatic Production ◽  
Oil Water

This study employed statistically based on experimental designs to optimize transesterification conditions for biodiesel production from waste oil via lipase-catalyzed in homoeothermy. Optimization of different reaction parameters were done by using response surface methodology. Results indicated optimum conditions including: alcohol to oil molar ratio 3:1, lipase concentration 58.38 U each gram of oil, water and n-hexane content were 24.59% and 13.28% respectively, reaction temperature at 20 °C , and reaction time for 24 h. Under these optimal conditions, 98.24% yield of biodiesel was obtained. This study will probably contribute to the development of continuous enzymatic processes, and maybe a suitable method for industrial production of biodiesel.

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