Recent progress in nanotechnology has provided high-performance nanomaterials for enzyme immobilization.Nanobiocatalysts combining enzymes and nanocarriers are drawing increasing attention because of their high cataly...Recent progress in nanotechnology has provided high-performance nanomaterials for enzyme immobilization.Nanobiocatalysts combining enzymes and nanocarriers are drawing increasing attention because of their high catalytic performance,enhanced stabilities,improved enzyme-substrate affinities,and reusabilities.Many studies have been performed to investigate the efficient use of cellulose nanocrystals,polydopamine-based nanomaterials,and synthetic polymer nanogels for enzyme immobilization.Various nanobiocatalysts are highlighted in this review,with the emphasis on the design,preparation,properties,and potential applications of nanoscale enzyme carriers and nanobiocatalysts.展开更多
Microfluidic,as the systems for using microchannel(micron-or sub-micron scale)to process or manipulate microflow,is being widely applied in enzyme biotechnology and biocatalysis.Microfluidic immobilized enzyme reactor...Microfluidic,as the systems for using microchannel(micron-or sub-micron scale)to process or manipulate microflow,is being widely applied in enzyme biotechnology and biocatalysis.Microfluidic immobilized enzyme reactor(MIER)is a tool with great value for the study of catalytic property and optimal reaction parameter in a flourishing and highly producing manner.In view of its advantages in efficiency,economy,and addressable recognition especially,MIER occupies an important position in the investigation of life science,including molecular biology,bioanalysis and biosensing,biocatalysis etc.Immobilization of enzymes can generally improve their stability,and upon most occasions,the immobilized enzyme is endowed with recyclability.In this review,the enzyme immobilization techniques applied in MIER will be discussed,followed by summarizing the novel developments in the field of MIER for biocatalysis,bioconversion and bioanalysis.The preponderances and deficiencies of the current state-of-the-art preparation ways of MIER are peculiarly discussed.In addition,the prospects of its future study are outlined.展开更多
This paper sets out to summarize the literatures based on immobilized enzyme bio-chromatography and its application in inhibitors screening in the last decade.In order to screen enzyme inhibitors from a mass of compou...This paper sets out to summarize the literatures based on immobilized enzyme bio-chromatography and its application in inhibitors screening in the last decade.In order to screen enzyme inhibitors from a mass of compounds in preliminary screening,multi-pore materials with good biocompatibility are used for the supports of immobilizing enzymes,and then the immobilized enzyme reactor applied as the immobilized enzyme stationary phase in HPLC.Therefore,a technology platform of high throughput screening is gradually established to screen the enzyme inhibitors as new anti-tumor drugs.Here,we briefly summarize the selective methods of supports,immobilization techniques,co-immobilized enzymes system and the screening model.展开更多
Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-...Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.展开更多
The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists...The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N?methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO2 electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The properties of the immobilized enzyme on CM-CADB were studied by investigating the initial rate of the enzyme reaction, the effect of various parameters on the immobilized GDC activity and its stability. An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO2 electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamate acid. The limit of detection is 1.0×10-5 M. The linearity response is in the range of 5×10 -2-5×10 -5 M . The equation of linear regression of the calibration curve is y= 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamate acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.展开更多
The immobilized technique of manganese peroxidase(MnP) in gelatin-containing microemulsion-based gels and the effects of storage time and reuse times on its catalytic activity were studied. The results show that the M...The immobilized technique of manganese peroxidase(MnP) in gelatin-containing microemulsion-based gels and the effects of storage time and reuse times on its catalytic activity were studied. The results show that the MnP immobilized together with Mn 2+ and H_2O_2 could effectively oxidize syringaldazine in n-heptane. The immobilized MnP still had a high catalytic activity after one-month storage under a freezing condition. The reuse times have a relation to the amount of the immobilized H_2O_2. When the amount of the immobilized H_2O_2 is sufficient, the microemulsion-based gels containing MnP could be used many times.展开更多
Capillary electrophoresis with many advantages plays an important role in pharmaceutical analysis and drug screening. This review gives an overview on the recent advances in the developments and applications of capill...Capillary electrophoresis with many advantages plays an important role in pharmaceutical analysis and drug screening. This review gives an overview on the recent advances in the developments and applications of capillary electrophoresis in the field of enzyme inhibitor screening. The period covers 2013 to 2017. Both the pre-capillary enzyme assays and in-capillary enzyme assays which include electrophoretically mediated microanalysis（EMMA） and immobilized enzyme microreactor（IMER） are summarized in this article.展开更多
Carboxyl-functionalized SBA-15(COOH/SBA-15)was prepared by a one-pot synthesis method and characterized.COOH-SBA-15/LZM-LP,an immobilized bi-enzyme(lipase and lysozyme),was prepared using COOH/SBA-15 as a carrier.The ...Carboxyl-functionalized SBA-15(COOH/SBA-15)was prepared by a one-pot synthesis method and characterized.COOH-SBA-15/LZM-LP,an immobilized bi-enzyme(lipase and lysozyme),was prepared using COOH/SBA-15 as a carrier.The orthogonal experiments were used to optimize the immobilization conditions with the index of corrosion inhibition.Electrochemical tests show that COOH-SBA-15/LZM-LP can significantly inhibit the corrosion of carbon steel in circulating cooling water.The corrosion inhibition rate was higher than 93%when the amount of COOHSBA-15/LZM-LP was 0.2 g/L.The inhibition mechanism was proposed and discussed from the perspective of carboxyl and enzymes.Finally,when COOH-SBA-15/LZM-LP was doped into epoxy resin,the corrosion resistance of epoxy coatings can be significantly improved,and the corrosion resistance only decreased by 0.23%after 720 h of soaking.展开更多
Plasma was purified in an immobilized L-asparaginase column. The predicted results are in good agreement with experimental data. It is indicated that the mathematical model is suitable for the mass transfer and react...Plasma was purified in an immobilized L-asparaginase column. The predicted results are in good agreement with experimental data. It is indicated that the mathematical model is suitable for the mass transfer and reaction of blood purification.展开更多
Magnetic nanoparticles（Fe3O4） were synthesized by co-precipitating Fe^2＋ and Fe^3＋ ions in an ammonia solution and treating under hydrothermal conditions.Cellulase was immobilized onto Fe3O4 magnetic nanoparticles...Magnetic nanoparticles（Fe3O4） were synthesized by co-precipitating Fe^2＋ and Fe^3＋ ions in an ammonia solution and treating under hydrothermal conditions.Cellulase was immobilized onto Fe3O4 magnetic nanoparticles via glutaraldehyde activation.Using response surface methodology and Box-Behnken design,the variables such as magnetic nanoparticle concentration,glutaraldehyde concentration,enzyme concentration,and cross linking time were optimized.The Box-Behnken design analysis showed a reasonable adjustment of the quadratic model with the experimental data.Statistical contour plots were generated to evaluate the changes in the response surface and to understand the relationship between the nanoparticles and the enzyme activity.Scanning electron microscopy,X-ray diffraction analysis,and Fourier transform infrared spectroscopy were studied to characterize size,structure,morphology,and binding of enzyme onto the nanoparticles.The stability and activity of the bound cellulase was analyzed using various parameters including pH,temperature,reusability,and storage stability.The immobilized cellulase was compared with free cellulase and it shows enhanced stability and activity.展开更多
Luciferase from firefly lantern extract was immobilized on CNBr activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. The K m′ for D luciferin is 11.9 μmol/L, the ...Luciferase from firefly lantern extract was immobilized on CNBr activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. The K m′ for D luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose bound enzyme were 7.8 and 25℃ respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10 -9 -10 -5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.展开更多
Transesterification between methyl-butyrate and 1-butanol in nonaqueous systems was catalyzed by porcine pancreatic lipase which was immobilized on cross- linked polystyrene. Organic solvents, substrate concentration,...Transesterification between methyl-butyrate and 1-butanol in nonaqueous systems was catalyzed by porcine pancreatic lipase which was immobilized on cross- linked polystyrene. Organic solvents, substrate concentration, contents of water and other parameters which affect the immobilized enzyme activity were studied. Lipase immobilized on hydrophobic crosslinked polystyrene can reduce its diffusion limit in the reaction. It was found that the activity of immobilized lipase in organic systems was two times as high as that of free lipase.展开更多
Porphyrin-filled nanofibrous membranes were facilely prepared by electrospinning of the mixtures of poly（acrylonitrile-co-acrylic acid）（PANCAA） and porphyrins. 5,10,15,20-Tetraphenylporphyrin（TPP） and its metal-...Porphyrin-filled nanofibrous membranes were facilely prepared by electrospinning of the mixtures of poly（acrylonitrile-co-acrylic acid）（PANCAA） and porphyrins. 5,10,15,20-Tetraphenylporphyrin（TPP） and its metal-loderivatives（ZnTPP and CuTPP） were studied as filling mediators for the immobilization of redox enzyme. Results indicate that the introduction of TPP, ZnTPP and CuTPP improves the retention activity of the immobilized catalase. Among these three porphyrins, the ZnTPP-filled PANCAA nanofibrous membrane exhibits an activity retention of 93%, which is an exciting improvement. This improvement is attributed to both the strong catalase-porphyrin affinity and the possible facilitated electron transfer induced by the porphyrin as evidenced by quartz crystal microbalance （QCM） and fluorescence spectroscopy studies.展开更多
This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was obt...This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was obtained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90℃, which is higher than that of free acylase I (60℃). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I.展开更多
Modular bioreactors can provide a flexible platform for constructing complex multi-step pathways,which may be a solution for maximizing reactions and overcoming the complexity of multi-enzyme systems.Here,we selected ...Modular bioreactors can provide a flexible platform for constructing complex multi-step pathways,which may be a solution for maximizing reactions and overcoming the complexity of multi-enzyme systems.Here,we selected wood-derived cellulose scaffold as a support for enzyme immobilization and constructed the modular bioreactor.Cellulose scaffold was prepared after removing lignin from wood,followed by citric acid functionalization and the addition of glutaraldehyde finally allowed the cross-linking of enzymes.Three enzymes,horseradish peroxidase(HRP),glucose oxidase(GOD),and catalase(CAT),were separately immobilized,resulting in the immobilized enzyme amount to over 40 mg/g.The introduction of carboxyl groups from citric acid facilitated the rapid enzyme adsorption on the support surface and immobilized enzymes possess~65%expressed activity.Modular bioreactors were constructed by using the immobilized enzymes.With the immobilized HRP module,reactor showed desired catalytic performance with the phenol degradation rate of>90%.Also,a pH regulation can occur in the bioreactors for preserving enzyme activities and neutralizing acid products.In the GOD/CAT modular bioreactor,the cascade reaction with adjusting pH values can achieve a 95%yield of sodium gluconate and exhibit a favorable reusability of 5 operation cycles.展开更多
Redox homeostasis,which is regulated by enzymes acting as regulatory valves,is crucial for maintaining the proper functioning of biomolecules and a stable microenvironment for physiological processes by modulating the...Redox homeostasis,which is regulated by enzymes acting as regulatory valves,is crucial for maintaining the proper functioning of biomolecules and a stable microenvironment for physiological processes by modulating the homeostasis of reactive oxygen species(ROS).Antioxidant enzymes in biocatalysis are used in the prevention or treatment of oxidative stress-related disease by counteracting the harmful effects of ROS.However,designing a system that can efficiently immobilize antioxidant enzymes with high catalytic activity and stability is still challenging.Bioinspired by photo-biocatalysis,a novel and effective catalase(CATase)-immobilized hydrogel platform has been developed by the proposed photo-enzymatic coupled radical polymerization strategy of the visible light coupling with the porphyrin-centered CATase.The higher catalytic stability and activity can therefore be achieved due to the preferential polymerization of CATase-immobilized hydrogel platform with a favorable three-dimensional network of enhanced coupling efficacy between light and enzymes.The mechanisms of free radical-initiated polymerization as well as the antioxidant cycle in the photo-CATase coupling system have been explored.Intriguingly,the CATase-immobilized hydrogel platform affords an unprecedented antioxidant ability to scavenge ROS and provide an effective cellular protection mechanism against external oxidative stress.Additionally,the CATase-immobilized hydrogel platform can effectively prevent peritoneal adhesion by reducing the expression of inflammatory cytokines.Therefore,the novel CATase-immobilized hydrogel platform is a potential candidate for physical barriers that effectively prevent postoperative adhesion formation,offering a new anti-adhesion strategy for clinical applications.展开更多
Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials,where the material properties are mainly influenced by the species of natural biomolecules,linear ...Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials,where the material properties are mainly influenced by the species of natural biomolecules,linear synthetic polymer,or small molecules,limiting their diversity.Herein,we adopted dendrimer poly(amidoamine)(PAMAM)as the inducer to synthesize organosilica-PAMAM network(OSPN)capsules for mannose isomerase(MIase)encapsulation based on a hard-templating method.The structure of OSPN capsules can be precisely regulated by adjusting the molecular weight and concentration of PAMAM,thereby demonstrating a substantial impact on the kinetic behavior of the MIase@OSPN system.The MIase@OSPN system was used for catalytic production of mannose from Dfructose.A mannose yield of 22.24% was obtained,which is higher than that of MIase in organosilica network capsules and similar to that of the free enzyme.The overall catalytic efficiency(kcat/Km)of the MIase@OSPN system for the substrate D-fructose was up to 0.556 s^(-1)·mmol^(-1)·L.Meanwhile,the MIase@OSPN system showed excellent stability and recyclability,maintaining more than 50% of the yield even after 12 cycles.展开更多
Dendritic mesoporous silica nanoparticles(DMSNs)are a new class of solid porous materials used for enzyme immobilization support due to their intrinsic characteristics,including their unique open central-radial struct...Dendritic mesoporous silica nanoparticles(DMSNs)are a new class of solid porous materials used for enzyme immobilization support due to their intrinsic characteristics,including their unique open central-radial structures with large pore channels and their excellent biocompatibility.In this review,we review the recent progress in research on enzyme immobilization using DMSNs with different structures,namely,flower-like DMSNs and tree-branch-like DMSNs.Three DMSN synthesis methods are briefly compared,and the distinct characteristics of the two DMSN types and their effects on the catalytic performance of immobilized enzymes are comprehensively discussed.Possible directions for future research on enzyme immobilization using DMSNs are also proposed.展开更多
Amphiphilic copolymer of 5-benzyloxytrimethylene carbonate （BTMC） with poly （vinyl pyrrolidone） （PVP） was successfully synthesized using immobilized porcine pancreas lipase （IPPL） or SnOct2 as catalyst. Hydrox...Amphiphilic copolymer of 5-benzyloxytrimethylene carbonate （BTMC） with poly （vinyl pyrrolidone） （PVP） was successfully synthesized using immobilized porcine pancreas lipase （IPPL） or SnOct2 as catalyst. Hydroxyl terminated PVP, synthesized with 2-mercaptoethanol as a chain transfer reagent, was employed as a rnacroinitiator. The resulting copolymers were characterized by GPC, ^1H NMR and IR. Increasing the BTMC/PVP-OH feed ratio （[B]/[P]） resulted in the increase of Mn of corresponding copolymers and the decrease of Mw/Mn. Immobilized enzyme has comparable catalytic activity to SnOct2 for the copolymerization.展开更多
Porcine pancreas lipase (PPL) and PPL immobilized on narrow distributed micron-sized glass beads wereemployed successfully for the ring-opening polymerization of 5, 5-dimethyl-1, 3-dioxan-2-one (DTC) for the first tim...Porcine pancreas lipase (PPL) and PPL immobilized on narrow distributed micron-sized glass beads wereemployed successfully for the ring-opening polymerization of 5, 5-dimethyl-1, 3-dioxan-2-one (DTC) for the first time.Different polymerization conditions such as enzyme concentration and reaction temperature were studied. Immobilized PPLexhibits higher activity than native PPL. Along wth the increasing enzyme concentration, the molecular weigh of resultingPDTC decreases. PPL immobilized on narrow distributed micron-sized glass beads has outstanding recyclability. For thethird recycle time, immobilized PPL exhibits the highest catalytic activity and with high activity even after the fifth recyletime for the synthesis of PDTC. The ~1H-NMR spectra indicate that decarboxylation does not occur during the ring-openingpolymerization.展开更多
基金supported by the National Natural Science Foundation of China(21336002,21222606,21376096)the Key Program of Guangdong Natural Science Foundation(S2013020013049)+2 种基金the Fundamental Research Funds for the Chinese Universities(2015PT002,2015ZP009)the Program of State Key Laboratory of Pulp and Paper Engineering(2015C04)the South China University of Technology Doctoral Student Short-Term Overseas Visiting Study Funding Project~~
文摘Recent progress in nanotechnology has provided high-performance nanomaterials for enzyme immobilization.Nanobiocatalysts combining enzymes and nanocarriers are drawing increasing attention because of their high catalytic performance,enhanced stabilities,improved enzyme-substrate affinities,and reusabilities.Many studies have been performed to investigate the efficient use of cellulose nanocrystals,polydopamine-based nanomaterials,and synthetic polymer nanogels for enzyme immobilization.Various nanobiocatalysts are highlighted in this review,with the emphasis on the design,preparation,properties,and potential applications of nanoscale enzyme carriers and nanobiocatalysts.
文摘Microfluidic,as the systems for using microchannel(micron-or sub-micron scale)to process or manipulate microflow,is being widely applied in enzyme biotechnology and biocatalysis.Microfluidic immobilized enzyme reactor(MIER)is a tool with great value for the study of catalytic property and optimal reaction parameter in a flourishing and highly producing manner.In view of its advantages in efficiency,economy,and addressable recognition especially,MIER occupies an important position in the investigation of life science,including molecular biology,bioanalysis and biosensing,biocatalysis etc.Immobilization of enzymes can generally improve their stability,and upon most occasions,the immobilized enzyme is endowed with recyclability.In this review,the enzyme immobilization techniques applied in MIER will be discussed,followed by summarizing the novel developments in the field of MIER for biocatalysis,bioconversion and bioanalysis.The preponderances and deficiencies of the current state-of-the-art preparation ways of MIER are peculiarly discussed.In addition,the prospects of its future study are outlined.
基金supported by the Province Natural Science Foundation of Shandong (Grant number 2009ZRB02230)
文摘This paper sets out to summarize the literatures based on immobilized enzyme bio-chromatography and its application in inhibitors screening in the last decade.In order to screen enzyme inhibitors from a mass of compounds in preliminary screening,multi-pore materials with good biocompatibility are used for the supports of immobilizing enzymes,and then the immobilized enzyme reactor applied as the immobilized enzyme stationary phase in HPLC.Therefore,a technology platform of high throughput screening is gradually established to screen the enzyme inhibitors as new anti-tumor drugs.Here,we briefly summarize the selective methods of supports,immobilization techniques,co-immobilized enzymes system and the screening model.
基金supported by grants from the National Key Research and Development Program of China(2021YFC2102805,2019YFD1101204)the National Natural Science Foundation of China(21878142,21776132)+3 种基金Key Research and Development Plan of Jiangsu Province(BE2020712)Key Research and Development Plan of Jiangsu Province(BE2019001)Jiangsu Natural Science Fund for Distinguished Young Scholars(BK20190035)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.
基金The Applied Fundamental Foundation of Jiangsu province P. R. China. Contract No BJ98041.
文摘The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N?methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO2 electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The properties of the immobilized enzyme on CM-CADB were studied by investigating the initial rate of the enzyme reaction, the effect of various parameters on the immobilized GDC activity and its stability. An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO2 electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamate acid. The limit of detection is 1.0×10-5 M. The linearity response is in the range of 5×10 -2-5×10 -5 M . The equation of linear regression of the calibration curve is y= 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamate acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.
文摘The immobilized technique of manganese peroxidase(MnP) in gelatin-containing microemulsion-based gels and the effects of storage time and reuse times on its catalytic activity were studied. The results show that the MnP immobilized together with Mn 2+ and H_2O_2 could effectively oxidize syringaldazine in n-heptane. The immobilized MnP still had a high catalytic activity after one-month storage under a freezing condition. The reuse times have a relation to the amount of the immobilized H_2O_2. When the amount of the immobilized H_2O_2 is sufficient, the microemulsion-based gels containing MnP could be used many times.
基金financial support from the National Natural Science Foundation of China (Grant nos. 81573384 and 21375101)
文摘Capillary electrophoresis with many advantages plays an important role in pharmaceutical analysis and drug screening. This review gives an overview on the recent advances in the developments and applications of capillary electrophoresis in the field of enzyme inhibitor screening. The period covers 2013 to 2017. Both the pre-capillary enzyme assays and in-capillary enzyme assays which include electrophoretically mediated microanalysis（EMMA） and immobilized enzyme microreactor（IMER） are summarized in this article.
基金Thanks to the support of the Shandong Provincial Natural Science Foundation(ZR2017MEM013)for this research.
文摘Carboxyl-functionalized SBA-15(COOH/SBA-15)was prepared by a one-pot synthesis method and characterized.COOH-SBA-15/LZM-LP,an immobilized bi-enzyme(lipase and lysozyme),was prepared using COOH/SBA-15 as a carrier.The orthogonal experiments were used to optimize the immobilization conditions with the index of corrosion inhibition.Electrochemical tests show that COOH-SBA-15/LZM-LP can significantly inhibit the corrosion of carbon steel in circulating cooling water.The corrosion inhibition rate was higher than 93%when the amount of COOHSBA-15/LZM-LP was 0.2 g/L.The inhibition mechanism was proposed and discussed from the perspective of carboxyl and enzymes.Finally,when COOH-SBA-15/LZM-LP was doped into epoxy resin,the corrosion resistance of epoxy coatings can be significantly improved,and the corrosion resistance only decreased by 0.23%after 720 h of soaking.
基金the National Natural Science Foundation of China (No. 29806006).
文摘Plasma was purified in an immobilized L-asparaginase column. The predicted results are in good agreement with experimental data. It is indicated that the mathematical model is suitable for the mass transfer and reaction of blood purification.
文摘Magnetic nanoparticles（Fe3O4） were synthesized by co-precipitating Fe^2＋ and Fe^3＋ ions in an ammonia solution and treating under hydrothermal conditions.Cellulase was immobilized onto Fe3O4 magnetic nanoparticles via glutaraldehyde activation.Using response surface methodology and Box-Behnken design,the variables such as magnetic nanoparticle concentration,glutaraldehyde concentration,enzyme concentration,and cross linking time were optimized.The Box-Behnken design analysis showed a reasonable adjustment of the quadratic model with the experimental data.Statistical contour plots were generated to evaluate the changes in the response surface and to understand the relationship between the nanoparticles and the enzyme activity.Scanning electron microscopy,X-ray diffraction analysis,and Fourier transform infrared spectroscopy were studied to characterize size,structure,morphology,and binding of enzyme onto the nanoparticles.The stability and activity of the bound cellulase was analyzed using various parameters including pH,temperature,reusability,and storage stability.The immobilized cellulase was compared with free cellulase and it shows enhanced stability and activity.
文摘Luciferase from firefly lantern extract was immobilized on CNBr activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. The K m′ for D luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose bound enzyme were 7.8 and 25℃ respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10 -9 -10 -5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.
文摘Transesterification between methyl-butyrate and 1-butanol in nonaqueous systems was catalyzed by porcine pancreatic lipase which was immobilized on cross- linked polystyrene. Organic solvents, substrate concentration, contents of water and other parameters which affect the immobilized enzyme activity were studied. Lipase immobilized on hydrophobic crosslinked polystyrene can reduce its diffusion limit in the reaction. It was found that the activity of immobilized lipase in organic systems was two times as high as that of free lipase.
基金Supported by the National High-Tech Research and Development Program of China(No.2007AA10Z301) the National Natural Science Foundation of China for Distinguished Young Scholars(No.50625309)
文摘Porphyrin-filled nanofibrous membranes were facilely prepared by electrospinning of the mixtures of poly（acrylonitrile-co-acrylic acid）（PANCAA） and porphyrins. 5,10,15,20-Tetraphenylporphyrin（TPP） and its metal-loderivatives（ZnTPP and CuTPP） were studied as filling mediators for the immobilization of redox enzyme. Results indicate that the introduction of TPP, ZnTPP and CuTPP improves the retention activity of the immobilized catalase. Among these three porphyrins, the ZnTPP-filled PANCAA nanofibrous membrane exhibits an activity retention of 93%, which is an exciting improvement. This improvement is attributed to both the strong catalase-porphyrin affinity and the possible facilitated electron transfer induced by the porphyrin as evidenced by quartz crystal microbalance （QCM） and fluorescence spectroscopy studies.
文摘This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was obtained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90℃, which is higher than that of free acylase I (60℃). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I.
基金supported by the National Key Research and Development Program of China(2021YFC2102804)the Beijing Natural Science Foundation(No.2202034)the National Natural Science Foundation of China(No.21978024)。
文摘Modular bioreactors can provide a flexible platform for constructing complex multi-step pathways,which may be a solution for maximizing reactions and overcoming the complexity of multi-enzyme systems.Here,we selected wood-derived cellulose scaffold as a support for enzyme immobilization and constructed the modular bioreactor.Cellulose scaffold was prepared after removing lignin from wood,followed by citric acid functionalization and the addition of glutaraldehyde finally allowed the cross-linking of enzymes.Three enzymes,horseradish peroxidase(HRP),glucose oxidase(GOD),and catalase(CAT),were separately immobilized,resulting in the immobilized enzyme amount to over 40 mg/g.The introduction of carboxyl groups from citric acid facilitated the rapid enzyme adsorption on the support surface and immobilized enzymes possess~65%expressed activity.Modular bioreactors were constructed by using the immobilized enzymes.With the immobilized HRP module,reactor showed desired catalytic performance with the phenol degradation rate of>90%.Also,a pH regulation can occur in the bioreactors for preserving enzyme activities and neutralizing acid products.In the GOD/CAT modular bioreactor,the cascade reaction with adjusting pH values can achieve a 95%yield of sodium gluconate and exhibit a favorable reusability of 5 operation cycles.
基金supported by the National Science Fund for Distinguished Young Scholars(52125305)the National Natural Science Foundation of China(52173289,52273147)the Key Project of the First Demonstration Project(Artificial intelligence)of Interdisciplinary Joint Research of Tongji University(ZD-11-202151)。
文摘Redox homeostasis,which is regulated by enzymes acting as regulatory valves,is crucial for maintaining the proper functioning of biomolecules and a stable microenvironment for physiological processes by modulating the homeostasis of reactive oxygen species(ROS).Antioxidant enzymes in biocatalysis are used in the prevention or treatment of oxidative stress-related disease by counteracting the harmful effects of ROS.However,designing a system that can efficiently immobilize antioxidant enzymes with high catalytic activity and stability is still challenging.Bioinspired by photo-biocatalysis,a novel and effective catalase(CATase)-immobilized hydrogel platform has been developed by the proposed photo-enzymatic coupled radical polymerization strategy of the visible light coupling with the porphyrin-centered CATase.The higher catalytic stability and activity can therefore be achieved due to the preferential polymerization of CATase-immobilized hydrogel platform with a favorable three-dimensional network of enhanced coupling efficacy between light and enzymes.The mechanisms of free radical-initiated polymerization as well as the antioxidant cycle in the photo-CATase coupling system have been explored.Intriguingly,the CATase-immobilized hydrogel platform affords an unprecedented antioxidant ability to scavenge ROS and provide an effective cellular protection mechanism against external oxidative stress.Additionally,the CATase-immobilized hydrogel platform can effectively prevent peritoneal adhesion by reducing the expression of inflammatory cytokines.Therefore,the novel CATase-immobilized hydrogel platform is a potential candidate for physical barriers that effectively prevent postoperative adhesion formation,offering a new anti-adhesion strategy for clinical applications.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC210-2300)the National Key Research and Development Program of China(Grant No.2022YFC2105902)+2 种基金Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(Grant No.TSBICIP-KJGG-003)Open Funding Project of the State Key Laboratory of Biochemical Engineering of China(Grant No.2020KF-06)Haihe Laboratory of Sustainable Chemical Transformations.
文摘Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials,where the material properties are mainly influenced by the species of natural biomolecules,linear synthetic polymer,or small molecules,limiting their diversity.Herein,we adopted dendrimer poly(amidoamine)(PAMAM)as the inducer to synthesize organosilica-PAMAM network(OSPN)capsules for mannose isomerase(MIase)encapsulation based on a hard-templating method.The structure of OSPN capsules can be precisely regulated by adjusting the molecular weight and concentration of PAMAM,thereby demonstrating a substantial impact on the kinetic behavior of the MIase@OSPN system.The MIase@OSPN system was used for catalytic production of mannose from Dfructose.A mannose yield of 22.24% was obtained,which is higher than that of MIase in organosilica network capsules and similar to that of the free enzyme.The overall catalytic efficiency(kcat/Km)of the MIase@OSPN system for the substrate D-fructose was up to 0.556 s^(-1)·mmol^(-1)·L.Meanwhile,the MIase@OSPN system showed excellent stability and recyclability,maintaining more than 50% of the yield even after 12 cycles.
基金supported by the National Natural Science Foundation of China(No.22178083)the Natural Science Foundation of Hebei Province(C2019208174 and B2022202014)+1 种基金the S&T Program of Hebei(20372802D,21372804D,and 21372805D)the Natural Science Foundation of Tianjin City(20JCYBJC00530)
文摘Dendritic mesoporous silica nanoparticles(DMSNs)are a new class of solid porous materials used for enzyme immobilization support due to their intrinsic characteristics,including their unique open central-radial structures with large pore channels and their excellent biocompatibility.In this review,we review the recent progress in research on enzyme immobilization using DMSNs with different structures,namely,flower-like DMSNs and tree-branch-like DMSNs.Three DMSN synthesis methods are briefly compared,and the distinct characteristics of the two DMSN types and their effects on the catalytic performance of immobilized enzymes are comprehensively discussed.Possible directions for future research on enzyme immobilization using DMSNs are also proposed.
基金the financial support of National Key Fundamental Research Program of China （Grant No. G1999064703） the National Natural Science Foundation of China （Grant No. 20104005）.
文摘Amphiphilic copolymer of 5-benzyloxytrimethylene carbonate （BTMC） with poly （vinyl pyrrolidone） （PVP） was successfully synthesized using immobilized porcine pancreas lipase （IPPL） or SnOct2 as catalyst. Hydroxyl terminated PVP, synthesized with 2-mercaptoethanol as a chain transfer reagent, was employed as a rnacroinitiator. The resulting copolymers were characterized by GPC, ^1H NMR and IR. Increasing the BTMC/PVP-OH feed ratio （[B]/[P]） resulted in the increase of Mn of corresponding copolymers and the decrease of Mw/Mn. Immobilized enzyme has comparable catalytic activity to SnOct2 for the copolymerization.
基金The authors are grateful for the financial support of the National Natural Science Foundation of China (No. 20104005) and Hubei Province Natural Science Foundation of China (No. 2001B053) and a grant from National Key Fundamental Research Program of Chin
文摘Porcine pancreas lipase (PPL) and PPL immobilized on narrow distributed micron-sized glass beads wereemployed successfully for the ring-opening polymerization of 5, 5-dimethyl-1, 3-dioxan-2-one (DTC) for the first time.Different polymerization conditions such as enzyme concentration and reaction temperature were studied. Immobilized PPLexhibits higher activity than native PPL. Along wth the increasing enzyme concentration, the molecular weigh of resultingPDTC decreases. PPL immobilized on narrow distributed micron-sized glass beads has outstanding recyclability. For thethird recycle time, immobilized PPL exhibits the highest catalytic activity and with high activity even after the fifth recyletime for the synthesis of PDTC. The ~1H-NMR spectra indicate that decarboxylation does not occur during the ring-openingpolymerization.
