scholarly journals Molecular Decoration of Ceramic Supports for Highly Effective Enzyme Immobilization—Material Approach

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 201
Author(s):  
Joanna Kujawa ◽  
Marta Głodek ◽  
Izabela Koter ◽  
Borys Ośmiałowski ◽  
Katarzyna Knozowska ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Immobilized Lipase ◽  
Material Surface ◽  
Specific Enzyme ◽  
Enzyme Loading ◽  
Enantiomeric Ratio ◽  
Highly Effective ◽  
Functionalized Materials ◽  
Specific Material ◽  
The Impact

A highly effective method was developed to functionalize ceramic supports (Al2O3 powders and membranes) using newly synthesized spacer molecules. The functionalized materials were subsequently utilized for Candida antarctica lipase B enzyme immobilization. The objective is to systematically evaluate the impact of various spacer molecules grafted onto the alumina materials will affect both the immobilization of the enzymes and specific material surface properties, critical to enzymatic reactors performance. The enzyme loading was significantly improved for the supports modified with shorter spacer molecules, which possessed higher grafting effectiveness on the order of 90%. The specific enzyme activity was found to be much higher for samples functionalized with longer modifiers yielding excellent enantioselectivity >97%. However, the enantiomeric ratio of the immobilized lipase was slightly lower in the case of shorter spacer molecules.

scholarly journals Parameters Affecting the Performance of Immobilized Enzyme

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Dong-Hao Zhang ◽  
Li-Xia Yuwen ◽  
Li-Juan Peng
Keyword(s):  
Enzyme Immobilization ◽  
Large Scale ◽  
Immobilized Enzyme ◽  
Immobilized Lipase ◽  
Industrial Process ◽  
Poor Performance ◽  
Current Status ◽  
Enzyme Loading ◽  
The Past ◽  
The Poor

Enzyme immobilization has been investigated to improve lipase properties over the past few decades. Different methods and various carriers have been employed to immobilize enzyme. However, the application of enzymatic technology in large scale is rarely seen during the industrial process. The main obstacles are a high cost of the immobilization and the poor performance of immobilized lipase. This review focuses on the current status of enzyme immobilization, which aims to summarize the latest research on the parameters affecting the performance of immobilized enzyme. Particularly, the effect of immobilization methods, immobilization carriers, and enzyme loading has been discussed.

scholarly journals Functionalized Materials as a Versatile Platform for Enzyme Immobilization in Wastewater Treatment

2021 ◽  
Author(s):  
Agnieszka Kołodziejczak-Radzimska ◽  
Long D. Nghiem ◽  
Teofil Jesionowski
Keyword(s):  
Wastewater Treatment ◽  
Enzyme Immobilization ◽  
Organic Dyes ◽  
Scientific Progress ◽  
Immobilized Enzymes ◽  
Chemical Oxidation ◽  
Biologically Active ◽  
Water Pollutants ◽  
Untreated Wastewater ◽  
Functionalized Materials

Abstract Purpose of Review Untreated wastewater discharge can significantly and negatively impact the state of the environment. Rapid industrialization and economic development have directly contributed to land and water pollution resulting from the application of many chemicals such as organic dyes, pharmaceuticals, and industrial reagents. The removal of these chemicals before effluent discharge is crucial for environmental protection. This review aims to explore the importance of functionalized materials in the preparation of biocatalytic systems and consider their application in eliminating water pollutants. Recent Findings Wastewater treatment methods can be classified into three groups: (i) chemical (e.g., chemical oxidation and ozonation), (ii) physical (e.g., membrane separation and ion exchange), and (iii) biological processes. Biological treatment is the most widely used method due to its cost-effectiveness and eco-friendliness. In particular, the use of immobilized enzymes has recently become more attractive as a result of scientific progress in advanced material synthesis. The selection of an appropriate support plays an important role in the preparation of such biologically active systems. Recent studies have demonstrated the use of various materials for enzyme immobilization in the purification of water. Summary This review identifies and discusses different biocatalytic systems used in the enzymatic degradation of various water pollutants. Materials functionalized by specific groups can serve as good support matrices for enzyme immobilization, providing chemical and thermal stability to support catalytic reactions. Enzymatic biocatalysis converts the pollutants into simpler products, which are usually less toxic than their parents. Due to immobilization, the enzyme can be used over multiple cycles to reduce the cost of wastewater treatment. Future studies in this field should focus on developing new platforms for enzyme immobilization in order to improve degradation efficiency.

A Review on Non-Asbestos Friction Materials: Material Composition and Manufacturing

2018 ◽  
Vol 1150 ◽  
pp. 22-42
Author(s):  
Dinesh Shinde ◽  
Kishore N. Mistry ◽  
Suyog Jhavar ◽  
Sunil Pathak
Keyword(s):  
Composite Materials ◽  
Material Properties ◽  
Single Phase ◽  
Friction Material ◽  
Material Surface ◽  
Surface Wear ◽  
Friction Modifier ◽  
Friction Materials ◽  
Morphological Studies ◽  
The Impact

The peculiar feature of friction materials to absorb the kinetic energy of rotating wheels of an automobile to control the speed makes them remarkable in automobile field. The regulation of speed cannot be achieved with the use of single phase material as a friction material. Consequently, the friction material should be comprised of composite materials which consist of several ingredients. Incidentally, the friction materials were formulated with friction modifier, binders, fillers and reinforcements. Due to its pleasant physical properties, asbestos was being used as a filler. Past few decades, it is found that asbestos causes dangerous cancer to its inhaler, which provides a scope its replacement. Several attempts have been made to find an alternative to the hazardous asbestos. The efforts made by different researchers for the impact of every composition of composite friction material in the field are reviewed and studied for their effect on the properties of friction material. Surface morphological studies of different friction material are compared to interpret the concept of surface wear and its correlation with material properties.

High Strength Autoclaved Mortars

1984 ◽  
Vol 42 ◽  
Author(s):  
R. Baggott ◽  
A. Sarandily
Keyword(s):  
Surface Energy ◽  
Modulus Of Elasticity ◽  
Preparation Method ◽  
High Strength ◽  
Dominant Factor ◽  
Material Surface ◽  
Specific Material

AbstractAutoclaved cement-silica mortars having flexural strengths of up to 57 MPa were prepared by pressing and casting methods of fabrication. It was found that the Griffith dependence of strength upon the size of the largest flaw, the modulus of elasticity and the surface energy was applicable. The relative contributions of these three parameters were evaluated and it was established that although the maximum flaw was the dominant factor in a specific material, surface energy changes were responsible for major strength differences associated with water-solid ratios or variations in the preparation method. Preliminary studies identified the various microstructural features that operated as Griffith's flaws.

scholarly journals The Spread of Corrosion in Cast Iron and its Effect on the Life Cycle of Transportation Vehicles

2017 ◽  
Vol 65 (2) ◽  
pp. 383-389 ◽  
Author(s):  
Tomáš Binar ◽  
Jiří Švarc ◽  
Petr Dostál ◽  
Michal Šustr ◽  
Jan Tippner
Keyword(s):  
Impact Strength ◽  
Fractographic Analysis ◽  
Bending Test ◽  
Material Surface ◽  
Bending Tests ◽  
Corrosion Tests ◽  
Fracture Surfaces ◽  
Impact Bending ◽  
Notch Impact Strength ◽  
The Impact

This article deals with the spread of corrosion in material at different exposure times, and its effect on the measured brittle fracture and notch impact strength under different temperature conditions. To assess the degradational effect of corrosion on the material characteristics represented by the measured impact strength, we conducted a fractographic analysis of fracture surfaces, the aim of which was to evaluate the spread of corrosion in the material. In the first part of the experiment, two corrosion tests are simulated with a duration time of 432 and 648 hours, to compare the degradation effect of corrosion on the notch impact strength, depending on the duration of the corrosion tests. The following part shows the results of the impact bending test, where the experiment was conducted in an area of reduced and increased temperatures. The final part summarizes the results of the fractographic analysis of sample fracture surfaces from the impact bending tests. Based on the measured the length of the corrosion cracks, we analyzed the sample at the notch and from the material surface after the impact bending test.

scholarly journals Effect of pH on membrane fouling during alcohol dehydrogenase immobilization in PES membrane

2020 ◽  
Vol 3 (2) ◽  
pp. 30
Author(s):  
Nurshahira Hazwani Hamran ◽  
Fauziah Marpani ◽  
Nur Hidayati Othman ◽  
Nik Raikhan Nik Him ◽  
Nur Hashimah Alias ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Enzyme Immobilization ◽  
Membrane Fouling ◽  
Feed Solution ◽  
Permeate Flux ◽  
Enzyme Loading ◽  
Solution Ph ◽  
Observed Rejection ◽  
Pes Membrane ◽  
Blocking Mechanism

Fouling-induced enzyme immobilization is a technique to immobilize enzyme by positively manipulating the knowledge of membrane fouling. In this study, Alcohol dehydrogenase (ADH) (EC 1.1.1.1) was immobilized in the support layer of ultrafiltration PES membrane at different solution pH (acid, neutral and alkaline). ADH catalyses formaldehyde (CHOH) to methanol (CH3OH) and simultaneously oxidised nicotinamide adenine dinucleotide (NADH) to NAD+. The initial feed amount of enzyme is 3.0 mg. The objective of the study aims at the effect of different pH of feed solution during enzyme immobilization, in terms of permeate flux, observed rejection, enzyme loading and fouling mechanism. The results showed that, pH 5 holds the highest enzyme loading which is 65% while pH 7 holds the lowest at 52% out of 3.0 mg as the initial enzyme feed. The permeate flux for each pH decreased with increasing cumulative permeate volume. The observed rejection is inversely correlated with the pH where increase in pH will cause a lower observed rejection. The fouling model predicted that irreversible fouling occurs during enzyme immobilization at pH 7 with standard blocking mechanism while reversible fouling occurs at pH 5 and 9 with intermediate and complete blocking, respectively.

scholarly journals Biocatalytic Reduction of Formaldehyde to Methanol: Effect of pH on Enzyme Immobilization and Reactive Membrane Performance

2021 ◽  
Vol 16 (3) ◽  
pp. 472-480
Author(s):  
Norhayati Abdul Rahman ◽  
Fauziah Marpani ◽  
Nur Hidayati Othman ◽  
Nur Hashimah Alias ◽  
Junaidah Jai ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Enzymatic Reaction ◽  
Feed Solution ◽  
Permeate Flux ◽  
High Concentration ◽  
Enzyme Loading ◽  
Reaction Conversion ◽  
Observed Rejection ◽  
Pes Membrane ◽  
Reactive Membrane

Thermodynamic stabled CO2 molecules can be biocatalytically reduced to methanol via three cascade dehydrogenases (formate, formaldehyde and alcohol) with the aid of cofactor as the electron donor. In this study, Alcohol dehydrogenase (EC 1.1.1.1), the third step of the cascade enzymatic reaction which catalyzed formaldehyde (CHOH) to methanol (CH3OH) will be immobilized in an ultrafiltration membrane. The enzyme will be immobilized in the support layer of a poly(ether)sulfone (PES) membrane via a technique called fouling induced enzyme immobilization. The objective of this study is to evaluate the effect of varying pH (acid (pH 5), neutral (pH 7) and alkaline (pH 9)) of the feed solution during immobilization process of ADH in the membrane in terms of permeate flux, observed rejection, enzyme loading and fouling mechanism. The experiment was conducted in a pressure driven, dead-end stirred filtration cell. Reaction conversion and biocatalytic productivity will be also evaluated. The results showed that permeate flux for acid solution were the lowest during immobilization. High concentration polarization and fouling resistance cause lower observed rejection for pH 7 and 9. Enzyme loading for pH 5 give 73.8% loading rate which is the highest compared to 62.4% at pH 7 and 70.1% at pH 9. Meanwhile, the conversion rate during the reaction shows that reaction on fouled membrane showed more than 90% conversion for pH 5 and 7. The fouling model predicted that irreversible fouling occurs during enzyme immobilization at pH 7 with standard blocking mechanism while reversible fouling occurs at pH 5 and 9 with intermediate and complete blocking, respectively. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

scholarly journals Impact of Structural Defects on the Surface Quality of Hardwood Species Sliced Veneers

2020 ◽  
Vol 10 (18) ◽  
pp. 6265
Author(s):  
Vasiliki Kamperidou ◽  
Efstratios Aidinidis ◽  
Ioannis Barboutis
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Wood Species ◽  
Research Work ◽  
Structural Defects ◽  
Material Surface ◽  
Typical Structure ◽  
Hardwood Species ◽  
The Impact

The surface roughness constitutes one of the most critical properties of wood and wood veneers for their extended utilization, affecting the bonding ability of the veneers with one another in the manufacturing of wood composites, the finishing, coating and preservation processes, and the appearance and texture of the material surface. In this research work, logs of five significant European hardwood species (oak, chestnut, ash, poplar, cherry) of Balkan origin were sliced into decorative veneers. Their surface roughness was examined by applying a stylus tracing method, on typical wood structure areas of each wood species, as well as around the areas of wood defects (knots, decay, annual rings irregularities, etc.), to compare them and assess the impact of the defects on the surface quality of veneers. The chestnut veneers presented the smoothest surfaces, while ash veneers, despite the higher density, recorded the highest roughness. In most of the cases, the roughness was found to be significantly lower around the defects, compared to the typical structure surfaces, probably due to lower porosity, higher density and the presence of tensile wood. The results reveal that the presence of defects does not affect the roughness of the veneers and increases neither the processing requirements of the veneer sheets before finishing, nor the respective production cost of veneers and the veneer-based wood panels. The high utilization prospects of the examined wood species in veneer production, even those bearing various defects, is highlighted.

Slurry Erosion Behaviors of Pseudoelastic TiNi Alloy

2007 ◽  
Author(s):  
Renbo Xu ◽  
Lishan Cui ◽  
Yanjun Zheng ◽  
Siwei Zhang
Keyword(s):  
Stainless Steel ◽  
Erosion Resistance ◽  
Deformation Mode ◽  
Experimental Results ◽  
Material Surface ◽  
Tini Alloy ◽  
Erosion Process ◽  
Slurry Erosion ◽  
Pile Up ◽  
The Impact

The slurry erosion behaviors of pseudoelastic TiNi alloy were studied using the liquid/solid impingement system and compared with SUS 630 and 2Cr12NiMo1W1V alloy. The influences of erosion time and angle on erosion resistance of three materials were surveyed. The experimental results show that TiNi alloy has the highest erosion resistance among the three materials and SUS 630 stainless steel is more resistant than 2Cr12NiMoW1V alloy. The KQL-300 indentation tester was used to simulate the impact of particle on material surface during erosion process. The results show that the deformation mode of indention can be pile-up or sink-in and there is a good correlation between erosion resistance of material and its indentation deformation mode. The sink-in deformation mode indicates the higher resistance to erosion, and the pile-up deformation mode implies the lower erosion resistance.

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