APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2013
·Vol. 172
·期 2
·701-712
·
IF 1.893
Cui Yanjun,Chen Xia,Li Yanfeng,Liu Xiao,Lei Lin,Zhang Yakui,Qian Jiayu
Using emulsion copolymer of styrene (St), glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA) as seed latexes, the superparamagnetic polymer emulsion particles were prepared by seeded emulsion copolymerization of butyl methacrylate (BMA), vinyl acetate (VAc) and ethylene glycol dimethacrylate in the presence of the seed latexes and superparamagnetic Fe 3 O 4 /SiOx nanoparticles (or Fe 3 O 4 -APTS nanoparticles) through a two-step process, without addition of any emulsifier. The magnetic emulsion particles named P(St-GMA-HEMA)/P(BMA-VAc) were characterized by transmission electron microscope and vibrating sample magnetometry. The results showed that the magnetic emulsion particles held a structure with a thinner shell (around 100 nm) and a bigger cavity (around 200 nm), and possessed a certain level of magnetic response. The resulting magnetic emulsion particles were employed in the immobilization of lipase by two strategies to immobilized lipase onto the resulting magnetic composites directly (S-1) or using glutaraldehyde as a coupling agent (S-2), thus, experimental data showed that the thermal stability and reusability of immobilized lipase based on S-2 were higher than that of S-1.
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MICROCHIMICA ACTA
·
2015
·Vol. 182
·期 7
·1387-1393
·
IF 3.741
Zhang Siqi,Sun Ting,Wang Jiahai
A biomimetic ion-responsive single nanopore sensor was constructed by immobilizing zirconium(IV) ion on a film of poly(ethylene terephthalate) whose surface was modified with polyethyleneimine (PEI) to form nanopores. PEI is an excellent metal-chelating ligand that was initially modified on the surface of the membrane through amidation. The Zr-chelated nanopore responds to inorganic phosphate by a change in the ion current–voltage plot. This is due to a reversal of the charge from positive to negative after binding of the phosphate to the tip of the ion channel. Inorganic phosphate can be quantified by measurement of the extent of rectification. The limit of detection of the method is 118 nM, and response is linear in the 0 to 40 μM phosphate concentration range. The formation of the Zr(IV)/phosphate system on the surface was corroborated by X-ray photoelectron spectroscopy and current–voltage characterization. The single synthetic nanopore display excellent selectivity, high sensitivity and a wide response range for phosphate. The accuracy of the method and applicability of the nanopore-based detection scheme was proven by the successful determination of inorganic phosphate in (spiked) lake water and a cola drink.
The Zr-chelated nanopore responds to inorganic phosphate by a change in the ion current–voltage plot due to a reversal of the charge from positive to negative after binding of the phosphate to the tip of the ion channel. Inorganic phosphate can be quantified by measurement of the extent of rectification. Nanopore-based assay can successful determine inorganic phosphate in (spiked) lake water and a cola drink.
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JOURNAL OF BIOTECHNOLOGY
·
2014
·
IF 2.884
Chengli Hu,Na Wang,Weiwei Zhang,Sheng Zhang,Yanfa Meng,Xiaoqi Yu
The aim of this study was to improve the ability of Aspergillus terreus lipase to separate the racemic ketoprofen vinyl ester into individual enantiomers using hollow self-assembly alginate- graft -poly(ethylene glycol)/α-cyclodextrins (Alg- g -PEG/α-CD) spheres as enzyme immobilization carriers. The morphology and size of the Alg- g -PEG/α-CD particles were investigated by transmission electron microscopy (TEM) and were found to be nanoscale. To facilitate recycling, calcium alginate (CA) beads were developed to encapsulate Alg- g -PEG/α-CD particles, thereby producing Alg- g -PEG/α-CD/CA composite beads. The influence of buffer pH and enzyme concentration during immobilization was studied along with the biocatalyst's kinetic parameters. When the immobilized enzyme was under optimal conditions in the resolution reaction, maximal conversion (approximately 45.9%) and enantioselectivity (approximately 128.8) were obtained. The immobilized A. terreus lipase maintained excellent performance even after 20 reuses and retained nearly 100% of its original activity after 24 weeks of storage at 4 °C.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2014
·
IF 3.065
Meng Wang,Xu Liu,Yu-xiang Jia,Xun-liang Wang
In this work, a three-step modification scheme was devised to covalently immobilize the polyethyleneimine (PEI) multilayers for improving the comprehensive transport properties of a heterogeneous cation exchange membrane (CEM), including the grafting of carboxyl groups, the PEI immobilization by amidation reaction and glutaraldehyde-induced PEI multilayers deposition. Firstly, the changes in surface chemical composition and morphology after modification were investigated by attenuated total reflection-Fourier transform infrared spectroscopy and scanning probe microscope. Then, the membrane properties corresponding to different modification steps were comprehensively evaluated by the measurements of ion exchange capacity, water content, salt permeability coefficient, membrane electrical resistance, limiting current density and so on. Especially, in order to simulate the possible applications in the reclamation of the industrial effluents from the hydrometallurgy processes and the comprehensive utilization of seawater, respectively, some electrodialysis experiments for H + /Zn 2+ system and Na + /Mg 2+ system were performed to estimate and compare the monovalent selectivity of the membrane samples. Furthermore, the alteration of surface heterogeneity after modification was explored by current–voltage curves and chronopotentiometric curves. The experimental results showed that the modification scheme proposed in this work can make significant contributions to a heterogeneous CEM, such as the endowment of monovalent cation permselectivity, the improvement of surface homogeneity for ameliorating concentration polarization, the ability to impeding salt diffusion and even the possibility of extending membrane life-span.
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BIOORGANIC CHEMISTRY
·
2024
·
IF 4.5
Wenbo Li,Xin Yan,Wenli Xia,Linguo Zhao,Jianjun Pei
Prenyltransferases catalyze the synthesis of prenylated flavonoids, providing these with greater lipid solubility, biological activity, and availability. In this study, a thermostable prenyltransferase (AfPT) from Aspergillus fumigatiaffinis was cloned and expressed in Escherichia coli . By optimizing induction conditions, the expression level of AfPT reached 39.3 mU/mL, which was approximately 200 % of that before optimization. Additionally, we determined the enzymatic properties of AfPT. Subsequently, AfPT was immobilized on carboxymethyl cellulose magnetic nanoparticles (CMN) at a maximum load of 0.6 mg/mg. Optimal activity of CMN-AfPT was achieved at pH 8.0 and 55 °C. Thermostability assays showed that the residual activity of CMN-AfPT was greater than 50 % after incubation at 55 °C for 4 h. Km and Vmax of CMN-AfPT for naringenin were 0.082 mM and 5.57 nmol/min/mg, respectively. The Kcat/Km ratio of CMN-AfPT was higher than that of AfPT. Residual prenyltransferase activity of CMN-AfPT remained higher than 70 % even after 30 days of storage. Further, CMN-AfPT retained 68 % of its original activity after 10 cycles of reuse. Compared with free AfPT, CMN-AfPT showed higher catalytic efficiency, thermostability, metal ion tolerance, substrate affinity, storage stability, and reusability. Our study presents a thermostable prenyltransferase and its immobilized form for the production of prenylated flavonoids in vitro .
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Chen Wang,Xiaohui Wu,Mingjie Huang,Tao Zhou,Juan Mao,Xiangling Zhang
Treatment of Cr(VI)-contaminated wastewaters by conventional reduction methods has been intensively challenged by alkaline environments. In this study, a novel copper-iron oxide composite (Cit@CuFeO) enriched with oxygen vacancies (OVs) was developed by ball milling with citric acid ligand (Cit). The material demonstrated efficient Cr(VI) removal within a broad pH range (6.0–12.0). Intriguingly, simultaneous and nearly complete in-situ immobilization of Cr(III) occurred, instead of precipitated in strong alkaline circumstances. Characterizations of the Cit@CuFeO revealed that ball milling of Cit could introduce abundant OVs into the oxide structure, serving as pivotal active sites linearly correlated with Cr(VI) capture and removal. These generated OVs could also boost electron conduction in Cit@CuFeO and cause a positive shift in the zeta potential , thereby enabling the adsorption of negative CrO 4 2- at high pH. Furthermore, DFT calculation verified that the surface-attached Cit would significantly decrease the adsorption energy of Cr(VI) at OVs sites, competitively excluding the occupancy of common inorganic anions especially CO 3 2– and thus favoring the Cr(III) immobilization under alkaline conditions. This study has provided a green functional material for the one-step remediation of alkaline Cr(VI) wastewaters without the need for acidification.
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MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 11
·1-12
·
IF 5.3
Wen Peng,Su Hao,Yin Wen-jia,Hu Jian-cheng,Wang Yu,Yang Jin-yi,Xiao Zhi-li,Xu Zhen-lin,Shen Yu-dong,Wang Hong,Hammock Bruce D.
A new type of label-free electrochemical immunosensor for the high-sensitivity determination of parathion was developed based on the oriented immobilization of nanobody (VHH9) on a gold nanoparticle-loaded polyvinyl alcohol/citric acid nanofiber membrane-modified electrode. The morphology characterization and assembly process of the modified materials were investigated using scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Under the optimum conditions, the label-free electrochemical immunosensor for parathion exhibited a linear range of 0.0015–6400 ng/mL and a low detection limit of 0.48 pg/mL, the signal response of which was 10 times higher than that of the randomly immobilized VHH9. The immunosensor possessed high selectivity, good repeatability and reusability (keeping above 90% of its initial activity after repeating 8 times), and stability (remaining 90% after 9 weeks of storage). Finally, the average recoveries of parathion from food samples were 93.76–105.73% with the coefficient of variation being 2.65–6.85%, showing good correlation with UPLC ( R 2 = 0.9950). Therefore, our nanobody immobilization protocol is simple and effective and proves the potential to be utilized as a promising candidate for sensing platform. Graphical
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yue Du,Chong-Mei Xu,Yu-Min Zhang,Zheng-Xuan Pan,Feng-Shan Wang,Hong-Ming Yang,Jin-Bao Tang
Covalent and oriented immobilization of antibodies (Abs) can substantially improve the sensitivity and stability of solid-phase immunoassays . By modifying the natural Abs with functional groups that provide unique handles for further conjugation, Abs could be immobilized onto the solid matrices with uniform orientation. Herein, an effective approach for Fc-specific modification of Abs was developed for the oriented and covalent immobilization of Abs. Twelve photoreactive Z -domain variants, incorporated with a photoactivable probe ( p -benzoyl- L -phenylalanine, Bpa) at different positions and carrying a C-terminal Cys-tag (i.e. Z Bpa -Cys variants), were individually constructed and produced in Escherichia coli and tested for photo-cross-linking to various IgGs. The different Z Bpa -Cys variants demonstrated large differences in photo-conjugation efficiency for the tested IgGs. The conjugation efficiencies of 17th Z Bpa -Cys ranged from 90 % to nearly 100 % for rabbit IgG and mouse IgG 2a , IgG 2b and IgG 3 . Other variants, including 5th Z Bpa -Cys, 18th Z Bpa -Cys, 32th Z Bpa -Cys, and 35th Z Bpa -Cys, also displayed conjugation efficiencies of 61 %–83 % for mouse IgG 1 , IgG 2a and IgG 3 . Subsequently, the photo-modified Abs, namely IgG–Cys conjugates, were covalently immobilized onto a maleimide group-functionalized solid-phase carrier on the basis of the reaction of sulfhydryl and maleimide . Thus, a generic platform for the controlled and oriented immobilization of Abs was developed, and the efficacy and potential of the proposed approach for sensitive immunoassays was demonstrated by detecting human α-fetoprotein.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhenlei Wang,Tingting Zhang,Yunliang Zhao,Yanhui Miao,Lingjie Zhang,Damiano Sarocchi,Shaoxian Song,Qiwu Zhang
Large scale of Cd-contaminated soil has become a serious threat to environmental safety and human health, whereas field applicability of existing remediation technologies has encountered numerous obstacles, such as poor stability, secondary pollution, long operation time, and high chemical cost. Herein, a novel activated calcite with significantly enhanced immobilization stability of Cd in soil has been synthesized based on mechanochemical technology. Our results demonstrate that the passivation rate of bioavailable Cd in Cd-contaminated soil (initial concentration 3 mg/kg) could be maintained at 65 % after 50 days of passivation cultured with activated calcite. Mechanistic studies have revealed that the outstanding performance is attributed to the enhancement of the CO 3 2– and Ca 2+ release properties of calcite through mechanical activation, leading to a 550 % increase in Ca 2+ release. The CO 3 2– fraction binds in situ to the free Cd in the soil, forming a stable carbonate-bound state. Simultaneously, the OH – released from the continuous hydrolysis of CO 3 2– effectively regulates and stabilizes the soil pH within the neutral range. Further, SEM-EDS and sequential extraction procedures (SEP) analyses implied that the specific adsorption of Cd by in-situ formed iron oxides in soil was visibly related to the release of OH – from activated calcite and immobilized the free state Cd in the more stable iron oxide-bound state. The current work shows the high sustainability and stability of Cd-contaminated soil immobilization by activated calcite materials.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Ayman K. El-Sawaf,Abdelrahman M. Abdelgawad,Amal A. Nassar,Dalia A. Elsherbiny
The increasing threat of spoilage bacterial infections, driven by the resistance of bacteria to many antimicrobial treatments, is a significant worldwide public health problem, especially concerning food preservation. To tackle these difficulties, this research investigates the possibility of using packaging sheets that include antimicrobial agents and increasing the prolonged storage time by preventing the bioburden of foodborne pathogens . This approach uses metal nanoparticles' ability to prevent harmful bacteria that cause food spoiling. Gallium nanoparticles (GaNPs) were created using a water-based extract from Andrographis paniculata leaves as a bioreducing agent. The GaNPs were added to a film made of sodium alginate (SA) and polyvinylpyrrolidone (PVP). The study showed that incorporating GaNPs into polymer films resulted in films with a desirable contact angle and decreased water vapor permeability. Significantly, the developed films demonstrated increased efficiency against E.coli O157 compared to other species. Also, it exhibited increased vulnerability to bacterial strains at the biofilm stage, surpassing PVP-SA/GaNPs-0. Remarkably, the toxicity tests showed that the films exhibited no cytotoxicity. Overall, the films indicated their potential for avoiding bacterial bioburden, prolonging the shelf life of perishable products , and contributing to diverse antimicrobial applications in the food industry.
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PREPARATIVE BIOCHEMISTRY & BIOTECHNOLOGY
·
2024
·
IF 2
Shanshan Tang,Jia Zhao,Chang Liu,Dezhi Huang,Jing Tian,Yi Yang
Coprinus comatus is an edible mushroom and its fermented product possesses antioxidant activity. In this study, to further enhance the antioxidant activity and improve the reusability of the strain, calcium alginate hydrogel was used as the carrier for embedding and immobilizing Coprinus comatus. The effects of CaCl2 concentration, sodium alginate concentration, microsphere diameter, and the amount of magnetic particle on the antioxidant activity of fermented products were investigated. The results showed that the magnetic immobilized microsphere prepared by 2.50% CaCl2, 2.00% sodium alginate and 0.50% Fe3O4 had the best fermentation antioxidant activity (EC50 was 0.43 ± 0.01 mg/mL) when the diameter was 5 mm, which increased by 24.56% compared to the initial activity. Besides, the microsphere showed strong reusability, the antioxidant activity was still better than the free strain after being used five times. This study not only enhanced the antioxidant activity of Coprinus comatus fermented product through immobilization, but also provided an effective method for microbial fermentation.
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Advanced Sustainable Systems
·
2025
·
IF 6.1
Jianle Zhou,Xiongliang He,Yanyan Ye,Zhuoxin Zhuang,Xingyu Tang,Junpeng Zhao,Yunjian Ma,Yonghua Wang
Fatty acid photodecarboxylase (FAP) plays a crucial role in the green production of biofuel and other valuable biochemicals. However, the reusability of immobilized FAP has been limited due to inadequate durability. Here, a porous, translucent chitosan hydrogel sphere carrier functionalized with cyclic carbonate group to enhance the reusability of immobilized FAP is presented. Based on the arrangement of basic amino acid residues on the surface of FAP, bis(cyclic carbonate) containing a flexible chain from CO 2 is designed and synthesized. This compound is used to modify porous hydrogels obtained via a template-etching process. FAP is then covalently immobilized within the hydrogel framework through a reaction with the remaining cyclic carbonate groups, as evidenced by quartz crystal microbalance analysis. The modified porous hydrogel carrier, PH3-BC-II, significantly improves the activity of FAP, achieving a maximum conversion of 70.0%, with the enzyme loading of 125.3 mg g −1 (dry carrier). Furthermore, PH3-BC-II retains >50% of its initial activity after eight consecutive reaction cycles (total runtime of 24 h) at high fatty acid substrate concentrations. This study provides an effective strategy for constructing stable immobilized (photo)enzymes from sustainable materials.
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