Maximum Catalytic Activity Research Articles

The Mechanism of Formation of Active Fe-TAMLs Using HClO Enlightens Design for Maximizing Catalytic Activity at Environmentally Optimal, Circumneutral pH.

Fe-TAML/peroxide catalysis provides simple, powerful, ultradilute approaches for removing micropollutants from water. The typically rate-determining interactions of H2O2 with Fe-TAMLs (rate constant kI) are sharply pH-sensitive with rate maxima in the pH 9-10 window. Fe-TAML design or process design that shifts the maximum rates to the pH 6-8 window of most wastewaters would make micropollutant eliminations even more powerful. Here, we show how the different pH dependencies of the interactions of Fe-TAMLs with peroxide or hypochlorite to form active Fe-TAMLs (kI step) illuminate why moving from H2O2 (pKa, ca. 11.6) to hypochlorite (pKa, 7.5) shifts the pH of the fastest catalysis to as low as 8.2. At pH 7, hypochlorite catalysis is 100-1000 times faster than H2O2 catalysis. The pH of maximum catalytic activity is also moderated by the pKa's of the Fe-TAML axial water ligands, 8.8, 9.3, and 10.3, respectively, for [Fe{4-NO2C6H3-1,2-(NCOCMe2NSO2)2CHMe}(H2O)n]- (2) [n = 1-2], [Fe{4-NO2C6H3-1,2-(NCOCMe2NCO)2CF2}(H2O)n]- (1b), and [Fe{C6H4-1,2-(NCOCMe2NCO)2CMe2}(H2O)n]- (1a). The new bis(sulfonamido)-bis(carbonamido)-ligated 2 exhibits the lowest pKa and delivers the largest hypochlorite over peroxide catalytic rate advantage. The fast Fe-TAML/hypochlorite catalysis is accompanied by slow noncatalytic oxidations of Orange II.

Synthesis and Characterization of New Lutidinium Ionic Liquid-Supported Vanadylsalicylaldoxime Complex for Catalytic Application in Epoxidation Reaction.

A new chelating task-specific ionic liquid (TSIL), lutidinium-based salicylaldoxime (LSOH), and its square pyramidal vanadyl(II) complex (VO(LSO)2 ) have been successfully synthesized and structurally characterized using elemental (CHN), spectral, and thermal analyses. The catalytic activity of the lutidinium-salicylaldoxime complex (VO(LSO)2 ) in the alkene epoxidation reactions was studied under various reaction conditions, such as solvent effect, alkene/oxidant molar ratio, pH, reaction temperature, reaction time, and the catalyst dose. The results demonstrated that the CHCl3 solvent, 1 : 3 of the cyclohexene/H2 O2 ratio, pH 8, temperature of 340 K, and catalyst dose of 0.012 mmol are assigned as the optimum conditions for achieving maximum catalytic activity for VO(LSO)2 . Moreover, the VO(LSO)2 complex has the potential for application in the effective and selective epoxidation of alkenes. Notably, under optimal VO(LSO)2 conditions, cyclic alkenes convert more efficiently to their corresponding epoxides than linear alkenes.

Characterization of a thermostable PL-31 family alginate lyase from Paenibacillus ehimensis and its application for alginate oligosaccharides bioproduction

Currently, people pay more attention to marine sugars, because of their unique physiological effects. Alginate oligosaccharides (AOS) are the degradation products of alginate and have been used in food, cosmetic, and medicine fields. AOS display good physical characteristics (low relative molecular weight, good solubility, high safety, and high stability) and excellent physiological functions (immunomodulatory, antioxidant, antidiabetic, and prebiotic activities). Alginate lyase plays a key role in the AOS bioproduction. In this study, a novel PL-31 family alginate lyase from Paenibacillus ehimensis (paeh-aly) was identified and characterized. It was extracellularly secreted in E. coli and exhibited a preference for the substrate poly β-D-mannuronate. Using sodium alginate as the substrate, it showed the maximum catalytic activity (125.7 U/mg) at pH 7.5 and 55 °C with 50 mM NaCl. Compared with other alginate lyases, paeh-aly exhibited good stability. About 86.6% and 61.0% residual activity could be maintained after 5 h incubation at 50 and 55 °C respectively, and its Tm value was 61.5 °C. The degradation products were AOS with DP 2–4. Paeh-aly demonstrated strong promise for AOS industrial production because of its excellent thermostability and efficiency.

Pd Thickness Optimization on Silicate Sheets for Improving Catalytic Activity (Adv. Mater. Interfaces 4/2023)

Optimizing Pd-Catalyst Activity The cover image represents a plate-like Pd particle supported on layered silicate nanosheets that require at least six layers of assembly to exhibit a metallic character and hence, a maximum catalytic activity in dehydro-coupling formic acid in aqueous media, as reported in article number 2202368 by Esmail Doustkhah, Nao Tsunoji, M. Hussein N. Assadi, and Yusuke Ide.

Metal-binding and folding thermodynamics of Escherichia coli ribonuclease HI related to its catalytic function

Escherichia coli ribonuclease HI (RNH) hydrolyzes the RNA strands of RNA/DNA hybrids in the presence of Mg2+ at the highest level, relative to other metal ions. The Mg2+ binding affinity was 8.39 × 103 M−1, which was lower than those of other metal ions. The low-affinity binder can express the maximum catalytic activity of RNH. The stability of RNH increased with increasing metal ion concentration, except for Zn2+. The thermodynamic origin for enhancing the stability of RNH with Mg2+ was more favorable entropy compared to those with other metal ions, indicating that Mg2+ binding changes the RNH structure while maintaining flexibility. Upon H124A mutation, the metal ion binding affinities decreased for Mn2+ and Zn2+ to a relatively large extent. The present thermodynamic analyses provide information on the structural dynamics of RNH with metal ion exchangeable binding, which can reasonably explain the metal-ion-dependent catalytic activity.

Monodispersed ultrathin twisty PdBi alloys nanowires assemblies with tensile strain enhance C2+ alcohols electrooxidation

Direct alcohol fuel cells (DAFCs) are powered by the alcohol electro-oxidation reaction (AOR), where an electrocatalyst with an optimal electronic structure can accelerate the sluggish AOR. Interestingly, strain engineering in hetero-catalysis offers a promising route to boost their catalytic activity. Herein, we report on a class of monodispersed ultrathin twisty PdBi alloy nanowires (TNWs) assemblies with face-centered structures that drive AORs. These thin nanowire structures expose a large number of reactive sites. Strikingly, Pd6Bi1 TNWs show an excellent current density of 2066, 3047, and 1231 mA mgPd−1 for oxidation of ethanol, ethylene glycol, and glycerol, respectively. The “volcano-like” behaviors observed on PdBi TNWs for AORs indicate that the maximum catalytic mass activity is a well balance between active intermediates and blocking species at the interface. This study offers an effective and universal method to build novel nanocatalysts in various applications by rationally designing highly efficient catalysts with specific strain.

Синтез и каталитическая активность высокодисперсных твердых растворов Ce0,9Sn0,1O2 и Ce0,8Sn0,1Zr0,1O2 в реакции окисления СО

Fluorite-like solid solutions of Ce0.9Sn0.1O2 and Ce0.8Sn0.1Zr0.1O2 are synthesized by co-precipitation using ammonium carbonate as a precipitant. The samples were characterized by X-ray phase analysis, electron microscopy, energy dispersive analysis, low-temperature nitrogen adsorption, and gas chromatography. It is shown that the formation of solid solutions occurs even at an annealing temperature of 550°C. In this case, the formation of lamellar particles occurs, the size of which, according to SEM data, is 4 μm. The synthesized materials have a mesoporous structure. The specific surface area of Ce0.9Sn0.1O2 samples is 80.6 m2/g, Ce0.8Zr0.1Sn0.1O2 is 76.3 m2/g. Carrying out the calcination at a temperature of 800 °C leads to an increase in the particle size up to 8 – 10 µm. The highest specific surface area of 15.3 m2/g is typical for the Ce0.8Zr0.1Sn0.1O2 sample, which is due to the presence of zirconium ions in its composition. The synthesized compositions demonstrated high activity in CO oxidation. The maximum catalytic activity was observed for the bicomponent system Ce0.9Sn0.1O2: T50% — 180°C, T90% — 236 °C. For samples calcined at a temperature of 800 °C, the most active is Ce0.8Zr0.1Sn0.1O2, which is due to the formation of a more thermally stable system compared to cerium dioxide and Ce0.9Sn0.1O2. To increase the thermal stability, it is advisable to dope the bicomponent composition Ce0.9Sn0.1O2 with Zr+4 ions.

Ultralow reaction barriers for CO oxidation in Cu-Au nanoclusters.

Systematic structure prediction of CunAum nanoclusters was carried out for a wide compositional area (n + m ≤ 15) using the evolutionary algorithm USPEX and DFT calculations. The obtained structural data allowed us to assess the local stability of clusters and their suitability for catalysis of CO oxidation. Using these two criteria, we selected several most promising clusters for an accurate study of their catalytic properties. The adsorption energies of reagents, reaction paths, and activation energies were calculated. We found several cases with low activation energies and explained these cases using the patterns of structural change at the moment of CO2 desorption. The unique case is the Cu7Au6 cluster, which has extremely low activation energies for all transition states (below 0.05 eV). We thus showed that higher flexibility due to the binary nature of nanoclusters makes it possible to achieve the maximum catalytic activity. Considering the lower price of copper, Cu-Au nanoparticles are a promising new family of catalysts.

Biochemical characterization of a psychrophilic and halotolerant α-carbonic anhydrase from a deep-sea bacterium, Photobacterium profundum.

Prokaryotic α-carbonic anhydrases (α-CA) are metalloenzymes that catalyze the reversible hydration of CO2 to bicarbonate and proton. We had reported the first crystal structure of a pyschrohalophilic α-CA from a deep-sea bacterium, Photobacterium profundum SS9. In this manuscript, we report the first biochemical characterization of P. profundum α-CA (PprCA) which revealed several catalytic properties that are atypical for this class of CA's. Purified PprCA exhibited maximal catalytic activity at psychrophilic temperatures with substantial decrease in activity at mesophilic and thermophilic range. Similar to other α-CA's, Ppr9A showed peak activity at alkaline pH (pH 11), although, PprCA retained 88% of its activity even at acidic pH (pH 5). Exposing PprCA to varying concentrations of oxidizing and reducing agents revealed that N-terminal cysteine residues in PprCA may play a role in the structural stability of the enzyme. Although inefficient in CO2 hydration activity under mesophilic and thermophilic temperatures, PprCA exhibited salt-dependent thermotolerance and catalytic activity under extreme halophilic conditions. Similar to other well-characterized α-CA's, PprCA is also inhibited by monovalent anions even at low concentrations. Finally, we demonstrate that PprCA accelerates CO2 biomineralization to calcium carbonate under alkaline conditions.

Heterostructured BiOCl–LaOCl S-scheme composites with improved visible-light photocatalytic activity on Rhodamine B dye

In this work, we report the synthesis of heterostructured BiOCl–LaOCl composites by using KCl as a source of chlorine and varying contents of LaOCl as raw materials in the presence of ethylene glycol at a temperature of 100 °C by using the solvothermal method. The prepared composites were characterized by X-ray diffraction, UV–Visible NIR spectroscopy, photoluminescence spectroscopy, SEM, TEM, EDX mapping, BET, and XPS analysis. TEM analysis revealed that the LaOCl particles were deposited on the surface of the BiOCl microspheres. The photo-efficiency of the BiOCl–LaOCl composite as photocatalyst was assessed by decomposing the Rhodamine B dye in an aqueous solution under irradiation from sunlight. The composite was found to have a higher rate of degradation of the dye solution than those of pure BiOCl and LaOCl semiconductors. The BiOCl–LaOCl‐1 composite exhibited the maximum catalytic activity of all the synthesized materials. The ability of the composite to degrade the dye was studied by using UV–Vis spectroscopy. The apparent rate of reaction of BiOCl–LaOCl‐1 was 0.1209 min−1, four and six times higher than those of BiOCl–LaOCl-2 and BiOCl, respectively. The results of the scavenger test revealed that the superoxide and hole radicals were mainly responsible for photodegradation. The high BET surface area of the composite also indicated enhanced photocatalytic activity.

Single crystal structure feature of a new 0D Cr(III) complex, a catalyst for mild peroxidative oxidation of toluene

[Cr(dipic)(2,2'-bipyridine).H 2 O] 2 .4H 2 O. 2 NO 3 (complex 1 ) • A new water-soluble inorganic complex of Cr(III) has been synthesized. • The complex presents a the triclinic system with the space group P 1 ¯ . • The complex was used for mild peroxidative oxidation of toluene. • The complex shows the maximum catalytic activity of 43.4% • The reactions to this complex appear to follow a radical mechanism. A novel water-soluble inorganic complex of Cr(III), formulated as [Cr(dipic)(2,2'-bipyridine).H 2 O] 2 .4H 2 O. 2(NO 3 ) (complex 1 ) where dipic 2- = pyridine 2,6-dicarboxylate was synthesized. Complex 1 has been characterized by elemental analysis, Fourier transformed-infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), and single-crystal X-Ray diffraction (SC-XRD). SC-XRD results revealed a triclinic system with space group P 1 ¯ for the expected composition. Each metal center is six-coordinates, and Cr(III) ions are in a distorted octahedral geometry. 1 is a zero-dimensional mononuclear complex that is expanded to a 3D supramolecular network by extensive hydrogen bonds between adjacent layers. The catalytic activity of complex 1 was evaluated towards the peroxidative oxidation (with hydrogen peroxide as a green oxidant) of toluene to the corresponding product (benzyl alcohol and benzaldehyde) in a homogenous medium under mild conditions. The influence of various parameters such as temperature, time, amounts of nitric acid, acetonitrile, catalyst, and n(H 2 O 2 )/n(catalyst) was evaluated to optimize the catalytic system. Complex 1 exhibited high efficiency in the homogeneous oxidation system without requiring the presence of an acid promoter. In this reaction, under optimized conditions, toluene was oxidized to benzyl alcohol and benzaldehyde with a maximum total yield of 43.4%. The study of the mechanism of reaction showed that this process is carried out through both carbon-centered and oxygen-centered radicals. Also, the reaction is promoted by the production of OH radicals that act as active oxidizing agents.

Following Paths of Maximum Catalytic Activity in the Composition Space of High‐Entropy Alloys

AbstractThe search for better and cheaper electrocatalysts is vital in the global transition to renewable energy resources. High‐entropy alloys (HEAs) provide a near‐infinite number of different alloys with approximately continuous properties such as catalytic activity. In this work, the catalytic activity for the electrochemical oxygen reduction reaction as a function of molar composition of Ag‐Ir‐Pd‐Pt‐Ru HEA is treated as a landscape wherein it is shown that the maxima are connected through ridges. By following the ridges, it is possible to navigate between the maxima using a modified nudged elastic band (NEB) model integrated in a machine learning NEB algorithm. These results provide a new understanding of the composition space being similar to an evolutionary landscape. This provides a possible new search and design strategy for new catalysts in which the composition of known catalysts can be optimized by following ridges rather than exploring the whole alloy composition space.

Combination of chemo and bio-based materials for the synthesis of Cu- Persimmon tannin -Perlite catalyst and its application for organic reaction

Cu-Persimmon tannin-Perlite (Cu-PT-P) composite was synthesized as a novel heterogenous organocatalyst by cross-linking reaction and using bio-based materials such as perlite and Persimmon tannin. The synthesis of Cu-PT-P composite was confirmed by several analyses, and the results were shown high stability of this catalyst. One of the important reactions in organic chemistry is Knoevenagel condensation reaction, which used for the synthesis of biologically compounds, and Cu-PT-P composite was applied to catalyze several aromatic aldehydes and malononitrile. The conditions of reaction were optimized under various solvents, catalyst-loading amounts, and time reaction. When ethanol was mixed to other compounds, maximum catalytic activity was obtained with high yield and short time, and Cu-PT-P composite can be recycled for five times without decrease of its activity. Based on the findings, Cu-PT-P composite can be applied for organic reaction as an inexpensive and benefit catalyst.

Optimization of the immobilization of xylanase from Thermomyces lanuginosus to produce xylooligosaccharides in a batch type reactor

The xylanase from Thermomyces lanuginosus was immobilized following very different protocols, using 3-aminopropyl (Xyl/CNT-NH2) and carboxylic acid (Xyl/CNT-C) functionalized multi-walled carbon nanotubes or after glutaraldehyde activation of CNT-NH2 (Xyl/CNT-Glu). It was also immobilized on carboxylic acid functionalized multi-walled carbon nanotubes via carbodiimide chemistry (Xyl/CNT-COOH). The free and all the immobilized xylanase derivatives showed maximal catalytic activity at pH 7.5 and at 65 °C. Xyl/CNT-Glu showed 24.0-fold higher thermal stability than the free xylanase at 70 °C. The immobilized xylanase derivatives were used for the production of xylooligosaccarides, the reaction courses and the yields showing a dependence on the immobilization protocol. The highest XOS yield (22.1%) was obtained using Xyl/CNT-Glu after 8 h of reaction at pH 75 and 65 °C.

Biotransformation of (-)-Isopulegol by Rhodococcus rhodochrous.

The ability of actinobacteria of the genus Rhodococcus to biotransform the monoterpenoid (–)-isopulegol has been established for the first time. R. rhodochrous strain IEGM 1362 was selected as a bacterium capable of metabolizing (–)-isopulegol to form new, previously unknown, 10-hydroxy (2) and 10-carboxy (3) derivatives, which may presumably have antitumor activity and act as respiratory stimulants and cancer prevention agents. In the experiments, optimal conditions were selected to provide the maximum target catalytic activity of rhodococci. Using up-to-date (TEM, AFM-CLSM, and EDX) and traditional (cell size, roughness, and zeta potential measurements) biophysical and microbiological methods, it was shown that (–)-isopulegol and halloysite nanotubes did not negatively affect the bacterial cells. The data obtained expand our knowledge of the biocatalytic potential of rhodococci and their possible involvement in the synthesis of pharmacologically active compounds from plant derivatives.

Depollution of Synthetic dyes From Waste Water Using Polyazomethine/TiO2 And Polyazomethine/ZnO Nanocomposites Via Photocatalytic Process

<p>We propose a simple method for synthesising Poly(azomethine), ZnO, TiO2, poly(azomethine)/TiO2, and poly(azomethine)/ZnO nanocomposites using an ultrasonication process, as well as the use of these nanomaterials for photocatalytic degradation of organic dyes (Methylene blue (MB), malachite green (MG), Bismarck brown (BB), alizarin red S (ARS), and (MO). Our findings show that precise control and optimization of ambient factors in the presence of natural sunlight can result in efficient tailoring of poly(azomethine)/TiO2 (PNT) and poly(azomethine)/ZnO (PNZ) nanocomposites. Compared to Poly(azomethine), ZnO, TiO catalysts, the PNT and PNZ composites exhibit better photocatalytic activity for MB, MG, BB, ARS, MO degradation, which could be attributed to the formation of special catalytically active structures on the nanocomposite surface. The synthesized PNT and PNZ composites had the maximum catalytic activity under circumstances of 500 mg photocatalyst dose, 5 h of sunlight exposure and 10 ppm dye concentrations. Under ideal conditions, MB degrades at a rate of 97 % after 5 h of sunlight exposure. The composites demonstrated selective dye degradation and have greater photocatalytic effectiveness for cationic dyes. This research could lead to the simple development of a high photocatalysts for the rapid removal of ecologically harmful dyes from aqueous solutions.</p>

Purification and characterization of a chitinase from Aeromonas media CZW001 as a biocatalyst for producing chitinpentaose and chitinhexaose.

Developing chitinase suitable for the bioconversion of chitin to chitin oligosaccharides has attracted significant attention due to its benefits in environmental protection. In this study, chitinase from Aeromonas media CZW001 (AmChi) was purified and characterized. The molecular weight of AmChi was approximately 40 kDa. AmChi exhibited maximum catalytic activity at pH 8.0 with an optimum temperature of 55°C and showed broad stability between 15 and 65°C and between pH 5.0 and 9.0. AmChi was activated by Mg2+ , Na+ , and K+ and inhibited by Hg+ , Co2+ , Fe2+ , Ca2+ , Ag+ , Zn2+ , and EDTA. The main products of AmChi on colloidal chitin were chitinhexaose and chitinpentaose. AmChi had better substrate specificity for powdered chitin than colloidal chitin and had a higher catalytic efficiency toward (GlcNAc)5 than colloidal chitin. AmChi inhibited fungal growth in a dose-dependent manner. These results suggest that AmChi could be used for the enzymatic degradation of chitin to produce chitinhexaose and chitinpentaose, which have several industrial applications.

Mechanistic basis for the allosteric activation of mitochondrial glutaminase C, a key driver of glutamine metabolism in cancer cells

The dependence of cancer cells on glutamine metabolism, the most abundant amino acid in plasma, has been observed in many highly aggressive and deadly cancers including pancreatic cancer, triple‐negative breast cancer, and glioblastoma. The mitochondrial enzyme glutaminase C (GAC) catalyzes the hydrolysis of glutamine to glutamate, the first step in glutamine metabolism, highlighting GAC as a potentially important therapeutic target. GAC acquires maximal catalytic activity upon binding to anionic activators like inorganic phosphate. To delineate the mechanism of GAC activation, we used the tryptophan substitution of tyrosine 466 in the catalytic site of the enzyme as a fluorescence reporter for glutamine binding in the presence and absence of phosphate. We show that in the absence of phosphate, glutamine binding to the GAC (Y466W) tetramer exhibits positive cooperativity. A high‐resolution X‐ray structure of tetrameric GAC (Y466W) bound to glutamine suggests that cooperativity in substrate binding is coupled to tyrosine 249, located at the edge of the catalytic site (i.e. designated the ‘lid’), adopting two distinct conformations. In one dimer within the GAC tetramer, the lids are open and glutamine binds weakly, whereas, in the adjoining dimer, the lids are closed over the substrates resulting in higher affinity interactions. When crystallized in the presence of glutamine and phosphate, all four subunits of the GAC (Y466W) tetramer have bound glutamine with closed lids. Glutamine now binds with high affinity to each subunit, which then undergo simultaneous catalysis. These findings show how the regulated transitioning of GAC between different conformational states ensures maximal catalytic activity is reached in cancer cells only when an allosteric activator is available.

Efficient production of cellobionic acid using whole-cell biocatalyst of genetically modified Pseudomonas taetrolens.

Pseudomonas taetrolens has previously been shown to convert cellobiose to cellobionic acid (CBA), which can potentially be used in cosmetics, food, and pharmaceutical industries. The cellobiose-oxidizing activity of the P. taetrolens strain, which expressed the homologous quinoprotein glucose dehydrogenase (GDH), was increased by approximately 50.8% compared to the original strain. Whole-cell biocatalyst (WCB) of the genetically modified P. taetrolens strain [pDSK-GDH] was prepared simply by fermentation and washing processes. Reaction conditions for the proper use of WCB, such as reaction temperature, cell density to be added, and cell harvest time for preparing WCB, were investigated. The highest CBA productivity (18.2g/L/h) was achieved when WCB prepared in the late-exponential phase of cell culture was used at 35°C with cell density of 10 at OD600nm. Under these conditions, 200g/L of cellobiose was all converted to CBA in 11h, and the WCB of P. taetrolens [pDSK-GDH] maintained the maximum catalytic activity during at least six cycles without a significant decline in the productivity. Our results suggest that the manufacture of WCB based on genetically engineered P. taetrolens and its optimized use could be further developed as an economically viable option for the large-scale production of CBA.

Different spacer-arm attached magnetic nanoparticles for covalent immobilization of Jack bean urease

Abstract Objectives This study aims the covalent immobilization of Jack bean urease on Fe3O4 magnetic nanoparticles via glutaraldehyde (urease@MNPs-Si-Glu) and epichlorohydrin (urease@MNPs-ECH) spacer arms. Methods The optimum pH and temperature, thermal, storage and reuse stability of free and immobilized urease preparations were investigated. Thermodynamics characterizations of free and immobilized urease preparations were also studied. Results The free urease and both immobilized urease preparations showed maximal catalytic activity at pH 7.5. The free urease had a maximal catalytic activity at 50 °C, while the both immobilized urease preparations exhibited their maximal catalytic activities at 70 °C. The urease@MNPs-Si-Glu and urease@MNP-ECH showed 2.7- and 1.9-fold higher thermal stability than the free urease at 60 °C, respectively. The free urease remained 30% of their initial activity at 4 °C, while urease@MNPs-Si-Glu and urease@MNPs-ECH retained 72 and 60% of their initial activities at the same conditions. The urease@MNPs-Si-Glu and urease@MNPs-ECH preserved 53 and 52% of their initial activities, respectively for urea hydrolysis after 20 reuses. Conclusions The urease@MNPs-Si-Glu and urease@MNPs-ECH may find a potential application area in urea hydrolysis.