Catalysts
·
2022
·Vol. 12
·期 9
·932
·
IF 4.501
Guoyun Sun,Ziyang Huang,Zhiqian Zhang,Yanfeng Liu,Jianghua Li,Guocheng Du,Xueqin Lv,Long Liu
Free enzymes often face economic problems due to their non-recyclability, which limits their applications for industrial manufacturing. Organic biopolymers are frequently used to fabricate hydrogel for enzyme immobilization due to their advantages of non-toxicity, biocompatibility, biodegradability, and flexibility. However, for highly thermostable enzymes, simple cross-linking causes either low immobilizing efficiency or low thermal stability. Herein, we developed a novel enzyme immobilization strategy with two-step cross-linked gelatin hydrogel for thermostable enzymes working at high temperature. The hydrogel was firstly “soft cross-linked” to immobilize most enzyme molecules and then “hard cross-linked” to gain strong thermal stability. We selected the enzyme diacetylchitobiose deacetylase (Dac), which was firstly derived from hyperthermophilic bacteria, to demonstrate the advantages of our method. With the optimized fabrication steps, our hydrogel showed ~87% Dac immobilization efficiency and excellent stability against heating, dehydrating, long-time storing, and massive recycling. Importantly, our hydrogel showed ~85.0% relative enzyme activity at 80 °C and retained ~65.8% activity after 10 rounds of catalysis. This strategy showed high immobilizing efficiency and strong thermal stability and we believe it could improve the industrial potential for those enzymes.Keywords:enzyme immobilization;gelatin hydrogel;two-step cross-linking;diacetylchitobiose deacetylase
研究领域:
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2023
·
IF 3.4
Xinqi Xu,Tianheng Chen,Lian Xu,Juan Lin
Laccase is an efficient biocatalyst for oxidative polymerization of organic substrates. However, cost of enzyme preparation , low stability and residual protein diminish the efficiency of laccase mediated polymerization. In this work, a series of silicon dioxide coated ferroferric oxide magnetic nanoparticles were modified by different functional groups including γ-methacryloxypropyltrimethoxy, succinic anhydride, glutaraldehyde and polyethylene imine. Infrared spectra indicated the magnetic carriers have been successfully modified. Vibrating sample magnetometer (VSM) analysis revealed that all of these carriers showed high magnetic responsiveness after the surface functionalization. Laccase from Cerrena sp. HYB07 was then respectively immobilized covalently on these functionalized magnetic carriers. All the immobilized laccases displayed higher thermostability than free laccase and glutaraldehyde functionalized support (named FSNG) immobilized laccase showed better performance. These immobilized laccases all showed higher efficiency than free laccase for oxidative polymerization of catechol and hydroquinone. The immobilized laccases could be separated from the water insoluble polymerization products. The polymerization product of hydroquinone by FSNG immobilized laccase showed the average polymerization degree of the poly(hydroquinone) was six (DP=6). This work provided a comprehensive exploration of laccase immobilization on magnetic carrier for catalyzing polymerization of phenols .
研究领域:
生物化学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
OPTIK
·
2023
·
IF 3.1
Chu Fenghong,Feng Yuan,Hu Anduo,Dai Caihong,Qi Yue,Bian Zhenglan
This paper proposes a cholesterol biosensor with hydrogel optical fiber immobilized with cholesterol oxidase . The hydrogel optical fiber with core and cladding structure was fabricated based on precursor solutions with two different concentrations of polyethylene glycol diacrylate (PEGDA). The concentration of fluorescent indicator in the hydrogel optical fiber core and the thickness of hydrogel cladding were optimized to obtain high performance cholesterol sensing. The sensing characteristics under different laser power, temperature, and pH were investigated. The experimental results showed that the photobleaching was reduced by appropriately decreasing the magnitude of laser power. The fluorescent indicator shows the best efficiency and stability when the ambient temperature is 25 °C and pH is 7. The linearity of the system was greater than 0.997 for cholesterol concentration in the range of 0.5–1.7 mg/mL, with good repeatability and response time of 4 mins. The precision of this sensor is 0.02 mg/mL. The hydrogel optical fiber with the advantage of flexibility, good ion permeability, and biocompatibility has broad application prospect in biomedical.
研究领域:
生物医学工程
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Fatima Mumtaz,Chaoshi Chen,Haikun Zhu,Chao Pan,Yanmei Wang
In this work, poly(2-methyl-2-oxazoline-random-glycidyl methacrylate) (PMOXA-r-GMA) and poly(acrylic acid)-block-poly(glycidyl methacrylate) (PAA-b-PGMA) copolymers were synthesized via cationic ring-opening polymerization (CROP) of 2-methyl-2-oxazoline (MOXA) and reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylic acid (AA) followed by their random and block copolymerization with glycidyl methacrylate (GMA), respectively, and then characterized carefully. PMOXA/PAA based coatings were then prepared by simply spin coating the mixture of PMOXA-r-GMA and PAA-b-PGMA copolymer solutions onto silicon/glass substrates followed by annealing at 110 °C. The coatings were rigorously characterized by using X-ray photoelectron spectroscopy (XPS), the static water contact angle (WCA) test, ellipsometry and atomic force microscopy (AFM). The results demonstrated that the coating based mixed PMOXA/PAA brushes with desired surface composition could be attained by simply maintaining their percentage in the mixture of PMOXA-r-GMA and PAA-b-PGMA copolymer solutions. Finally, the switchable behavior of PMOXA/PAA based coatings toward bovine serum albumin (BSA) adsorption was investigated by fluorescein isothiocyanate-labelled BSA (FITC-BSA) assay and quartz crystal microbalance with dissipation monitoring (QCM-D), which indicated that the coating based mixed PMOXA/PAA brushes could control BSA adsorption/desorption from very low to high amount (>90% desorption) through adjusting the composition of PMOXA-r-GMA and PAA-b-PGMA solution used in preparing PMOXA/PAA based coatings upon pH and ionic strength change. Furthermore, PMOXA/PAA based coatings displayed efficient repeatability of reversible BSA adsorption/desorption cycles.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
Sensor Letters
·
2016
·Vol. 14
·期 6
·623-629
·
IF 0
Li Liping,Liu Xiaojia,Xiao Qian,Zheng Yizhi,Wang Suiping,Feng Bo
A novel antibody immobilization method was developed for enzyme-linked immunosorbent assay (ELISA). The proposed method utilizes amine-bearing polymer macromolecules, namely, polyamidoamine (PAMAM) or polyethylenimine (PEI) to enhance antibody binding on polystyrene (PS) microwells,
as well as staphylococcal protein A (SPA) to realize orientation immobilization. After carboxylating the PS microwells with the solution of potassium permanganate (KMnO4) in diluted sulfuric acid (H2SO4), the PS surface was activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide
hydrochloride and N-hydroxysuccinimide and then grafted with PAMAM or PEI to introduce free amino groups. Glutaraldehyde was subsequently added to conjugate the amino groups and SPA prior to antibody adsorption. X-ray photoelectron spectroscopy and atomic force microscopy were performed to
investigate the morphology of the PS surfaces before and after different treatments. The immunoglobulin binding sites were confirmed through anti-Fab and anti-Fc ELISA kits. Results from the alpha fetoprotein ELISA kit showed that the use of both PAMAM and SPA is the optimal method for antibody
immobilization. In this treatment, absorbance exhibited an evident gradient with antigen concentrations and reached higher values over 200 ng/mL antigen compared with the ones of other methods.
研究领域:
生物化学
·
分子生物学
·
分析化学
✓ 已验证
DOI
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Mengnan Han,Xiaozheng Li,Xuming Wang,Dexu Liu,Shuangqing Fu,Wenzhi Xu,Wei Li,Honglei Zhang
A polyhydroxyalkanoate (PHA) magnetic microsphere was designed for one-step purification and immobilization of a novel carbonyl reductase (RLSR5) from recombinant Escherichia coli lysate. The hydrophobic core of this microsphere was composed of a highly biocompatible polymer, poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) (PHBHHx), in which magnetic Fe 3 O 4 particles were embedded during solvent evaporation. The hydrophilic shell of the fusion protein formed by PHA particle-binding protein (PhaP) and RLSR5 (PR) was expressed in recombinant E. coli . The magnetic core of Fe 3 O 4 @PHBHHx directly purified the hydrophilic shell from the E. coli lysate, and the two self-assembled to form Fe 3 O 4 @PHBHHx-PR through hydrophobic and hydrophilic interactions, eliminating the separation of the fusion protein. The microstructure, magnetic properties, morphology, size, and dispersion of Fe 3 O 4 @PHBHHx-PR were investigated by XRD, VSM, SEM, TEM, elemental mapping and DLS. It was found that Fe 3 O 4 @PHBHHx-PR correctly assembled, with a well dispersed spherical structure at the nanoscale and superparamagnetism properties. The amount of RLSR5 immobilized on PHA microspheres reached 121.9 mg/g. The Fe 3 O 4 @PHBHHx-PR was employed to synthesize (R )-tolvaptan with 99 % enantiomeric excess and 97 % bioconversion efficiency, and the catalyst maintained 78.6 % activity after 10 recovery cycles. These PHA magnetic microspheres are versatile carriers for enzyme immobilization and demonstrate improved stability and reusability of the free enzyme .
研究领域:
生物技术
·
酶工程
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Wei Su,Ping Liu,Changqing Cai,Hongzhi Ma,Bo Jiang,Yi Xing,Yunyi Liang,Liping Cai,Changlei Xia,Quyet Van Le,Christian Sonne,Su Shiung Lam
The dispersion of hyperaccumulators used in the phytoremediation process has caused environmental concerns because of their heavy metal (HM) richness. It is important to reduce the environmental risks and prevent the HM to reenter the ecological cycle and thereby the human food web. In this work, supercritical water gasification (SCWG) technology was used to convert Sedum plumbizincicola into hydrogen (H 2 ) gas and to immobilize HMs into biochar. The H 2 production correlated with temperature ranging from 380 to 440 ℃ with the highest H 2 yield of 2.74 mol/kg at 440 ℃. The free-radical reaction and steam reforming reaction at high temperatures were likely to be the mechanism behind the H 2 production. The analyses of bio-oil by the Gas Chromatography-Mass Spectrometer (GC–MS) and Nuclear magnetic resonance spectroscopy (NMR) illustrated that the aromatic compounds, oxygenated compounds, and phenols were degraded into H 2 -rich gases. The increase of temperature enhanced the HM immobilization efficiency (>99.2 % immobilization), which was probably due to the quickly formed biochar that helped adsorb HMs. Then those HMs were chemically converted into stable forms through complexation with inorganic components on biochar, e.g., silicates, SiO 2 , and Al 2 O 3 . Consequently, the SCWG process was demonstrated as a promising approach for dispersing hyperaccumulators by immobilizing the hazardous HMs into biochar and simultaneously producing value-added H 2 -rich gases.
研究领域:
环境科学
·
能源技术
·
植物学
✓ 已验证
DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 11
·期 10
·3609-3618
·
IF 6.119
Palle Ramana Murthy,Jing-Cai Zhang,Wei-Zhen Li
Pd-Based catalysts are efficient for methane combustion but impractical at high temperatures due to the sintering effect. Herein, we report a thermally stable Pd/SBA-15 catalyst that was prepared by using the sol-immobilization (SI) method, instead of the conventional incipient wetness impregnation (IWI) method. Pd nanoparticles retain the small size of ∼5 nm in the channels of SBA-15 in Pd/SBA-15-SI even after aging at 800 °C in air for 3 days, while those in the Pd/SBA-15-IWI samples aggregate into particles larger than 10 nm over the surface. The thermally stable Pd/SBA-15-SI indeed displays excellent catalytic activity for methane combustion at low temperatures with T50 at ∼300 °C and T90 at ∼350 °C and high stability during cyclic operations, which are much superior to those of the Pd/SBA-15-IWI catalysts. Interestingly, hydrothermal treatment of the Pd/SBA-15-SI catalysts leads to partial re-dispersion of Pd to form smaller particles of ∼1.6 nm, while the catalytic activity decreases a bit. Steam in the reactant mixture has a negative effect on the catalytic activity of Pd/SBA-15-SI catalysts, presumably due to the competitive adsorption of H2O to O2/CH4. Significantly, the size of Pd nanoparticles is essential to the catalytic performance and those having sizes of ∼5 nm are the most active. Finally, the catalytic activity of the catalysts in the presence of CO2 was studied. This work might be helpful in designing stable metal catalysts using porous materials for reactions under harsh conditions.
研究领域:
催化化学
·
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2014
·Vol. 29
·期 5
·1071-1077
·
IF 0.422
Qiu Bingsong,Mai Weizhong,Zeng Rong,Tu Mei,Zhao Jianhao,Zha Zhengang
Heparin was covalently immobilized onto polyurethane surface via a PEG spacer by a microwave-assisted approach to improve blood compatibility. Firstly, amino-terminated poly(ethylene glycol) (APEG) was rapidly grafted onto PU surface within 20 min by a two-step method involving microwave-assisted MDI-functionalization and subsequent microwave-assisted APEG coupling. Then, heparin was covalently immobilized through an amide linkage by the direct coupling of the carboxylic acid of heparin with the amino group of APEG on PU surface using carbodiimide coupling reaction. The surface structure and properties were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurements. The results revealed that heparin-immobilized PU surface had slightly increased roughness and significantly improved hydrophilicity in comparison to the original PU surface. The anticoagulant activity of films was evaluated by whole blood clotting time (CT) and prothrombin time (PT). Complement activation was assessed by detecting complement fragment 3a concentrations of serum exposed to the films. The results revealed that the microwave-assisted heparin-immobilized PU films had excellent antithrombogenicity and suppressed complement activation, indicating improved blood compatibility.
研究领域:
生物医学工程
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2012
·Vol. 127
·期 6
·4251-4255
·
IF 1.289
Wentao Liu,Hongdong Duan,Xia Meng,Dawei Qin,Xingjian Wang,Juan Zhang
A series of macroporous beaded terpolymers with epoxy groups were synthesized by suspension polymerization with glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA), and the third monomers including styrene, methyl methacrylate, n -butyl acrylate (BA), butyl methacrylate (BMA), and 2-hydroxyethyl methacrylate for immobilization of Candida lipolytica lipase. The effect of various third monomers on loading and activity recovery of immobilized lipase were studied. Terpolymers with BA as the third monomer were found to give the biggest loading of lipase, and the activity recovery of lipase immobilized on poly(GMA-EGDMA-BA) terpolymers reached 79.0%. As the content of BA (%) increasing, the loading of lipase enhanced, but the activity recovery reached 88.5% for the initial stage and decreased to 46.9% at last. The poly(GMA-EGDMA-BA-10) showed an optimal result in lipase immobilization. Lipase immobilized on poly(GMA-EGDMA-BA-10) carriers had broader pH and higher temperature stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
研究领域:
生物化学
·
高分子科学
·
酶工程
·
生物催化
·
材料化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
·
2014
·
IF 2.745
Teng Zhang,Xiao-Ling Xu,Yi-Ning Jin,Jian Wu,Zhi-Kang Xu
Carbon nanotubes are widely applied in electronics, which offers great potential for enhancing the activity of redox enzyme. In this work, polyimide (PI) was blended with multiwalled carbon nanotubes (MWCNTs) and then electrospun into nanofibers for the immobilization of horseradish peroxidase (HRP), a redox enzyme. SEM and TEM were used to characterize the surface morphology of the PI/MWCNTs nanofibers and to analyze the protruding parts induced by the blending of MWCNT. The results indicate that, compared to the virgin PI nanofibers, the blending of MWCNTs increases the retention activity of immobilized HRP from 2.38% to 12.50%. Circular dichroism and UV–vis molecular absorption spectrometry were used to explore the interactions between HRP and MWCNTs . It seems that MWCNTs increase the enzyme activity by the facilitation of electron transfer among the catalytic intermediates “HRP I”, “HRP II” and MWCNTs.
研究领域:
生物化学
·
纳米生物技术
·
酶工程
·
生物材料
·
分析化学
✓ 已验证
DOI
高影响因子
BIOCATALYSIS AND BIOTRANSFORMATION
·
2016
·
IF 0.892
Yanmei Wei,Hui Luo,Yanhong Chang,Huimin Yu,Zhongyao Shen
In this study, a recombinant cephalosporin C acylase (CCA) was covalently or physically immobilized on an epoxy-activated support LX1000-EPC4 (EP) or its derivatives, EP-polyethyleneimine (EP-PEI) and EP-ethylenediamine (EP-EDA) with cationic groups on the surface. Zeta potential was used as a tool for activated carrier analysis and immobilization analysis. The EP-PEI (the cationic polymer PEI grafted support) showed higher zeta potential than EP-EDA (the small diamine EDA modified support) and EP support. Among these three supports, immobilization of CCA on EP-PEI had the highest specific activity according to the range of enzyme loadings. Michaelis constant Km values of EP-PEI-CCA and EP-EDA-CCA were 22 mM and 30 mM, respectively, which were lower than that of the free enzyme (43 mM), suggesting that the support’s zeta potential is related to the affinity of the enzyme for the substrate. The enzyme immobilized on EP-PEI showed a much higher thermal stability (stabilization factor of 32-fold compared with the free enzyme) than that on the EP-EDA (stabilization factor of 5.5-fold) and EP supports (stabilization factor of 1.7-fold). The adsorption of CCA on EP-PEI support was very strong and reversible. The CCA could be thoroughly desorbed using a high concentration of NaCl (e.g., 2 M) at low pH value (pH 3.0). The regenerated EP-PEI support could then be reused for enzyme immobilization.
研究领域:
酶工程
·
生物催化
·
蛋白质固定化
·
应用微生物学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）