scholarly journals Enzymatic Bioreactors: An Electrochemical Perspective

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1232
Author(s):  
Simin Arshi ◽  
Mehran Nozari-Asbemarz ◽  
Edmond Magner
Keyword(s):  
Direct Electron Transfer ◽  
High Surface ◽  
High Surface Area ◽  
Enzyme Engineering ◽  
Future Perspective ◽  
Enzymatic System ◽  
Reaction Conditions ◽  
Flow Reactors ◽  
Recent Developments ◽  
Enzyme Cascades

Biocatalysts provide a number of advantages such as high selectivity, the ability to operate under mild reaction conditions and availability from renewable resources that are of interest in the development of bioreactors for applications in the pharmaceutical and other sectors. The use of oxidoreductases in biocatalytic reactors is primarily focused on the use of NAD(P)-dependent enzymes, with the recycling of the cofactor occurring via an additional enzymatic system. The use of electrochemically based systems has been limited. This review focuses on the development of electrochemically based biocatalytic reactors. The mechanisms of mediated and direct electron transfer together with methods of immobilising enzymes are briefly reviewed. The use of electrochemically based batch and flow reactors is reviewed in detail with a focus on recent developments in the use of high surface area electrodes, enzyme engineering and enzyme cascades. A future perspective on electrochemically based bioreactors is presented.

scholarly journals Towards a Novel Computer-Aided Optimization of Microreactors: Techno-Economic Evaluation of an Immobilized Enzyme System

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 524
Author(s):  
Philip Pietrek ◽  
Manfred Kraut ◽  
Roland Dittmeyer
Keyword(s):  
Magnetic Beads ◽  
Glucose Dehydrogenase ◽  
Packed Bed ◽  
Detailed Knowledge ◽  
Reaction Conditions ◽  
Flow Reactors ◽  
Continuous Flow Reactors ◽  
Enzyme Cascades ◽  
And Control ◽  
Physical And Chemical

Immobilized multi-enzyme cascades are increasingly used in microfluidic devices. In particular, their application in continuous flow reactors shows great potential, utilizing the benefits of reusability and control of the reaction conditions. However, capitalizing on this potential is challenging and requires detailed knowledge of the investigated system. Here, we show the application of computational methods for optimization with multi-level reactor design (MLRD) methodology based on the underlying physical and chemical processes. We optimize a stereoselective reduction of a diketone catalyzed by ketoreductase (Gre2) and Nicotinamidadenindinukleotidphosphat (NADPH) cofactor regeneration with glucose dehydrogenase (GDH). Both enzymes are separately immobilized on magnetic beads forming a packed bed within the microreactor. We derive optimal reactor feed concentrations and enzyme ratios for enhanced performance and a basic economic model in order to maximize the techno-economic performance (TEP) for the first reduction of 5-nitrononane-2,8-dione.

Efficient and Reusable Silica Gel Supported Metal Ionic Liquid Catalysts for Palmitic Acid Esterification to Biodiesel

2021 ◽  
Vol 43 (1) ◽  
pp. 1-1
Author(s):  
Guo Yingwei Guo Yingwei ◽  
Chen Xuedan Chen Xuedan ◽  
Yan Shiting Yan Shiting ◽  
Zhang Zhengliang Zhang Zhengliang ◽  
Chen Yuqin Chen Yuqin ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Palmitic Acid ◽  
Silica Gel ◽  
High Surface ◽  
High Surface Area ◽  
Kinetic Studies ◽  
Catalytic Performance ◽  
Reaction Conditions ◽  
Acid Esterification ◽  
Supported Metal

A series of silica gel (SG) supported metal ionic liquid catalysts (x[Bmim]Cl-CrCl3/SG) were synthesized and exploited for the esterification of palmitic acid (PA) with methanol (ML) to produce biodiesel efficiently. The 10%[Bmim]Cl-CrCl3/SG catalyst with high surface area and desirable acidity exhibited the best catalytic performance and reusability after six consecutive running cycles. Based on the response surface analysis, the optimal reaction conditions were obtained as follows: methanol/acid mole ratio = 11:1 mol/mol, catalyst amount = 5.3 wt%, reaction time = 65 min, as well as reaction temperature = 373 K, reaching to a biodiesel yield of 96.1%. Further kinetic studies demonstrated that the esterification of PA with ML obeyed 1.41 order kinetics for acid concentration with the activation energy of 16.88 kJ/mol

scholarly journals Catalytic Activity of High-Surface-Area Amorphous MgO Obtained from Upsalite

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1338
Author(s):  
Marek Gliński ◽  
Ewa M. Iwanek (nee Wilczkowska) ◽  
Urszula Ulkowska ◽  
Agnieszka Czajka ◽  
Zbigniew Kaszkur
Keyword(s):  
Surface Area ◽  
Carbonyl Compounds ◽  
Main Product ◽  
High Surface ◽  
High Surface Area ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Reaction Conditions ◽  
Synthesis Conditions ◽  
Transfer Hydrogenation Reaction

The first aim of the research was to synthesize a pure Upsalite, which is an amorphous form of MgCO3, by modifying a procedure described in the literature, so that it would be the precursor of a high-surface, amorphous magnesium oxide. The results indicate that within the studied reaction conditions, the type of alcohol used as the reactant has the most pronounced effect on the yield of reaction. From the two alcohols that led to the highest yield of Upsalite, methanol gave a substantially larger surface area (794 vs. 191 m2 g−1). The optimized synthesis conditions of Upsalite were used to obtain MgO via thermolysis, whose activity in the transfer hydrogenation reaction (THR) from ethanol, 2-propanol and 2-pentanol to various carbonyl compounds was determined. The optimal conditions for the thermolysis were as follows: vacuum, T = 673 K as the final temperature, and a heating rate of 2 deg min−1. The high-surface, amorphous magnesia (SBET = 488 m2 g−1) was found to be a very selective catalyst to 4-t-butylcyclohexanone in THR, which led to a diastereoselectivity of over 94% to the E-isomer of 4-t-butylcyclohexanol for more than 3 h, with conversions of up to 97% with either 2-propanol or 2-pentanol as the hydrogen donor. In the case of acrolein and 2-n-propylacrolein being used as the hydrogen acceptors, the unsaturated alcohol (UOL) was the main product of the reaction, with higher UOL yields noted for ethanol than 2-propanol.

Efficient and Reusable Silica Gel Supported Metal Ionic Liquid Catalysts for Palmitic Acid Esterification to Biodiesel

2021 ◽  
Vol 43 (1) ◽  
pp. 1-1
Author(s):  
Guo Yingwei Guo Yingwei ◽  
Chen Xuedan Chen Xuedan ◽  
Yan Shiting Yan Shiting ◽  
Zhang Zhengliang Zhang Zhengliang ◽  
Chen Yuqin Chen Yuqin ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Palmitic Acid ◽  
Silica Gel ◽  
High Surface ◽  
High Surface Area ◽  
Kinetic Studies ◽  
Catalytic Performance ◽  
Reaction Conditions ◽  
Acid Esterification ◽  
Supported Metal

A series of silica gel (SG) supported metal ionic liquid catalysts (x[Bmim]Cl-CrCl3/SG) were synthesized and exploited for the esterification of palmitic acid (PA) with methanol (ML) to produce biodiesel efficiently. The 10%[Bmim]Cl-CrCl3/SG catalyst with high surface area and desirable acidity exhibited the best catalytic performance and reusability after six consecutive running cycles. Based on the response surface analysis, the optimal reaction conditions were obtained as follows: methanol/acid mole ratio = 11:1 mol/mol, catalyst amount = 5.3 wt%, reaction time = 65 min, as well as reaction temperature = 373 K, reaching to a biodiesel yield of 96.1%. Further kinetic studies demonstrated that the esterification of PA with ML obeyed 1.41 order kinetics for acid concentration with the activation energy of 16.88 kJ/mol

Concluding remarks: there's nowt so queer as carbon electrodes

2014 ◽  
Vol 172 ◽  
pp. 521-532 ◽  
Author(s):  
Patrick R. Unwin
Keyword(s):  
Carbon Materials ◽  
Local Density ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Electrodes ◽  
Key Points ◽  
Recent Developments ◽  
History Of ◽  
History Of Use ◽  
The Impact

This contribution provides a personal overview and summary of Faraday Discussion 172 on “Carbon in Electrochemistry”, covering some of the key points made at the meeting within the broader context of other recent developments on carbon materials for electrochemical applications. Although carbon electrodes have a long history of use in electrochemistry, methods and techniques are only just becoming available that can test long-established models and identify key features for further exploration. This Discussion has highlighted the need for a better understanding of the impact of surface structure, defects, local density of electronic states, and surface functionality and contamination, in order to advance fundamental knowledge of various electrochemical processes and phenomena at carbon electrodes. These developments cut across important materials such as graphene, carbon nanotubes, conducting diamond and high surface area carbon materials. With more detailed pictures of structural and electronic controls of electrochemistry at carbon electrodes (and electrodes generally), will come rational advances in various technological applications, from sensors to energy technology (particularly batteries, supercapacitors and fuel cells), that have been well-illustrated at this Discussion.

Applications of Gold Nanoparticles in Biosensors

Nano LIFE ◽  
2016 ◽  
Vol 06 (02) ◽  
pp. 1642001 ◽  
Author(s):  
Xinjun Yu ◽  
Yang Jiao ◽  
Qinyuan Chai
Keyword(s):  
Heavy Metals ◽  
Gold Nanoparticles ◽  
Optical Properties ◽  
Metal Nanoparticles ◽  
Surface Area ◽  
Surface Functionalization ◽  
High Surface ◽  
High Surface Area ◽  
Synthetic Methods ◽  
Future Perspective

Gold nanoparticles (AuNPs) as one of the most stable metal nanoparticles have demonstrated extensive applications in recent years. This paper will give a focus on the AuNPs as biosensors, due to their inertness, unique optical properties, high surface area, and various surface functionalization methods. Synthesis of AuNps and the surface functionalization will be discussed in the first part. The size, shape, and stability can be controlled by different synthetic methods, while reductant usually needed. By surface functionalization with different molecules such as polymers, nucleic acids, and proteins, AuNPs will aggregate when specified molecule linkages showing up enables selective detections. The application in biosensing to detect proteins, oligonucleotide, glucose, and heavy metals will be exemplified, followed by the summary and future perspective part in the conclusion.

scholarly journals MgO nanoparticles: Synthesis, characterization, and applications as a catalyst for organic transformations

2021 ◽  
Vol 12 (1) ◽  
pp. 86-108
Author(s):  
Harshal Dabhane ◽  
Suresh Ghotekar ◽  
Pawan Tambade ◽  
Shreyas Pansambal ◽  
Rajeshwari Oza ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Catalytic Performance ◽  
Organic Transformations ◽  
Reaction Conditions ◽  
Synthesis Of Nanoparticles ◽  
Oxidation Reduction ◽  
Product Separation ◽  
Shape Selective ◽  
Catalytic Applications

Currently, the size and shape selective synthesis of nanoparticles (NPs) and their varied catalytic applications are gaining significant enthusiasm in the field of nanochemistry. Homogeneous catalysis is crucial due to its inherent benefits like high selectivity and mild reaction conditions. Nevertheless, it endures with serious disadvantages of catalysts and/or product separation/recycles compared to their heterogeneous counterparts restricting their catalytic applications. The utilization of catalysts in the form of nano-size is an elective methodology for the combination of merits of homogeneous and heterogeneous catalysis. Magnesium oxide (MgO) NPs are important as they find applications for catalysis, organic transformation, and synthesis of fine chemicals and organic intermediates. The applications of MgO NPs in diverse organic transformations including oxidation, reduction, epoxidation, condensation, and C-C, C-N, C-O, C-S bond formation in a variety of notable heterocyclic reactions are also discussed. The use of MgO NPs in organic transformation is advantageous as it mitigates the use of ligands; the procurable separation of catalyst for recyclability makes the protocol heterogeneous and monetary. MgO NPs gave efficacious catalytic performance towards the desired products due to high surface area. By considering these efficient merits, scientists have focused their attentions towards stupendous applications of MgO NPs in selective organic transformation. In the current review article, we summarized the synthesis of MgO NPs and numerous characterization techniques, whereas the application section illustrates their utility as a catalyst in several organic transformations. We believe this decisive appraisal will provide imperative details to further advance the application of MgO NPs in selective catalysis.

scholarly journals MCM-41 Supported Co-Based Bimetallic Catalysts for Aqueous Phase Transformation of Glucose to Biochemicals

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 843 ◽  
Author(s):  
Somayeh Taghavi ◽  
Elena Ghedini ◽  
Federica Menegazzo ◽  
Michela Signoretto ◽  
Delia Gazzoli ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Bimetallic Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Mesoporous Structure ◽  
Acid Sites ◽  
Weak Acid ◽  
Reaction Conditions ◽  
Temperature Programmed ◽  
Mcm 41

The transformation of glucose into valuable biochemicals was carried out on different MCM-41-supported metallic and bimetallic (Co, Co-Fe, Co-Mn, Co-Mo) catalysts and under different reaction conditions (150 °C, 3 h; 200 °C, 0.5 h; 250 °C, 0.5 h). All catalysts were characterized using N2 physisorption, Temperature Programmed Reduction (TPR), Raman, X-ray Diffraction (XRD) and Temperature Programmed Desorption (TPD) techniques. According to the N2-physisorption results, a high surface area and mesoporous structure of the support were appropriate for metal dispersion, reactant diffusion and the formation of bioproducts. Reaction conditions, bimetals synergetic effects and the amount and strength of catalyst acid sites were the key factors affecting the catalytic activity and biochemical selectivity. Sever reaction conditions including high temperature and high catalyst acidity led to the formation mainly of solid humins. The NH3-TPD results demonstrated the alteration of acidity in different bimetallic catalysts. The 10Fe10CoSiO2 catalyst (MCM-41 supported 10 wt.%Fe, 10 wt.%Co) possessing weak acid sites displayed the best catalytic activity with the highest carbon balance and desired product selectivity in mild reaction condition. Valuable biochemicals such as fructose, levulinic acid, ethanol and hydroxyacetone were formed over this catalyst.

Photochemical Water Oxidation Using {PMo12O40@Mo72Fe30}n Based Soft Oxometalate

2017 ◽  
Vol 05 (01) ◽  
pp. 1750001 ◽  
Author(s):  
Santu Das ◽  
Soumyajit Roy
Keyword(s):  
Water Oxidation ◽  
Oxidation Reaction ◽  
Alternative Energy ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Energy Resource ◽  
Clean Energy ◽  
Reaction Conditions ◽  
Reaction Cycles

Finding an alternative energy resource which can produce clean energy at a low cost is one of the major concerns of our times. The conversion of light energy into chemical energy is one key step forward in the direction. With that end in view photochemical water oxidation to produce oxygen plays a crucial role. In the present paper we have synthesized a soft oxometalate {PMo[Formula: see text]O[Formula: see text]@Mo[Formula: see text]Fe[Formula: see text]}n(1) from its well-known precursor polyoxometalate constituent [Muller et al., Chem. Commun. 1, 657 (2001)]. It is known that in the matter of catalysis, high surface area, possibility of heterogenization, recoverability makes soft oxometalates (SOMs) attractive as catalytic materials. Here we exploit such advantages of SOMs. The SOM based material acts as an active catalyst for photochemical water oxidation reaction with a maximum turnover number of 20256 and turnover frequency of 24.11[Formula: see text]min[Formula: see text]. The catalyst material is stable under photochemical reaction conditions and therefore can be reused for multiple photo catalytic water oxidation reaction cycles.

TiO2 nanofibers resembling ‘yellow bristle grass’ in morphology by a soft chemical transformation

2015 ◽  
Vol 44 (20) ◽  
pp. 9637-9645 ◽  
Author(s):  
Sandeep Nandan ◽  
T. G. Deepak ◽  
Shantikumar V. Nair ◽  
A. Sreekumaran Nair
Keyword(s):  
Surface Area ◽  
Chemical Transformation ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Conditions ◽  
Tio2 Nanofibers ◽  
One Dimensional

We synthesized a uniquely shaped one-dimensional (1-D) TiO2 nanostructure having the morphology of yellow bristle grass with high surface area by the titanate route under mild reaction conditions.

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