FOOD CHEMISTRY
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2020
·
IF 6.306
Weiping Jin,Zhifeng Wang,Dengfeng Peng,Wangyang Shen,Zhenzhou Zhu,Shuiyuan Cheng,Bin Li,Qingrong Huang
The co-existence of polysaccharides and enzymes in the food matrix could form complexes that directly influence the catalytic efficacy of enzymes. This work investigated the self-assembly behaviors of α-amylase and charged polysaccharides and fabricated the α-amylase/polysaccharides complex coacervates. The results showed that the linear charge density of polysaccharides had a critical impact on the complex formation, structure, and enzyme protection under acidic conditions. At low pH, α-amylase formed compact and tight coacervates with the λ-carrageenan. However, α-amylase/pectin coacervates dissociated when the pH was lower than 3.0. The optimized binding ratio of α-amylase/λ-carrageenan was 12:1, and α-amylase/pectin was 4:1. Finally, the α-amylase/λ-carrageenan complex coacervates effectively immobilized the enzyme and almost 70% of enzyme activity remained in coacervates after exposure to pH3.0 for 1 h. This study demonstrates that the change in the linear charge density of polysaccharides could regulate the enzyme-catalyzed process in food processing by a simple and fine-controlled method.
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高影响因子
ANALYST
·
2019
·Vol. 145
·期 1
·268-276
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IF 4.019
Guoning Chen,Hua Shu,Lu Wang,Kamran Bashir,Qun Wang,Xia Cui,Xuan Li,Zhimin Luo,Chun Chang,Qiang Fu
Immobilized enzymes play significant roles in many practical applications. However, the enzymes need to be purified before immobilization by conventional immobilizing methods, and the purification process is expensive, laborious, complicated and results in a decrease of the enzymatic activity. So, we present a novel method by a facile one-step targeted immobilization of an enzyme without a purification process from complex samples. For this purpose, a novel molecularly imprinted polymer was prepared via a silane emulsion self-assembly method using boric acid-modified Fe3O4 nanoparticles as magnetic nuclei, horseradish peroxidase as a template, 3-aminopropyltriethoxysilane as a functional monomer and tetraethyl orthosilicate as a crosslinking agent. The molecularly imprinted polymers were characterized using a scanning electron microscope, X-ray photoelectron spectroscope, vibrating sample magnetometer and X-ray diffractometer. The as-prepared and characterized materials were employed to immobilize horseradish peroxidase from a crude extract of horseradish. Moreover, the immobilized horseradish peroxidase was employed to develop visual sensors for the detection of glucose and sarcosine. This study demonstrated that the molecularly imprinted polymers prepared via the silane emulsion self-assembly method can facilely immobilize horseradish peroxidase from a crude extract of horseradish without any purification process. The developed visual method based on the immobilized horseradish peroxidase shows great potential applications for the visual detection of glucose and sarcosine.
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Materials Today Communications
·
2023
·
IF 3.8
Ruoning Chu,Xiaojie Guo,Yongjun Zhang,Xiaoyu Zhao,Xiantao Xiong,Xiujuan Zhang,Fengyi Zhang,Kun Zhang,Yaxin Wang
Water containing heavy metal ions can be extremely harmful to the environment and human body, thus the development of low-cost and high-efficient adsorbents has an exciting prospect. In this study, lignin/graphene aerogels modified with polydopamine and polyethyleneimine , respectively, were successfully prepared to remove Cr(VI) from aqueous waste. The physicochemical properties of graphene aerogels (GA), lignin/graphene aerogels (LGA), polydopamine-modified lignin/graphene aerogels (LGA@PDA), polyethyleneimine-modified lignin/graphene aerogels (LGA@PEI) were investigated using FT-IR, Raman spectroscopy , XRD , XPS , SEM-EDS, and BET analysis. The results demonstrate that adsorbents have a high specific surface area, an interconnected porous structure, and a large number of oxygen-containing groups, making them particularly favorable for heavy metal adsorption. The effects of GO/lignin ratio, surface modifiers, solution pH, contact time, initial concentration and temperature on the Cr(VI) removal were investigated and compared via batch experiments. Compared with GA (138.74 ± 3.93 mg/g), the adsorption capacity of LGA with GO/LA ratio 40:1 increased to 167.66 ± 4.75 mg/g. Furthermore, the maximum adsorption capacity of LGA@PEI and LGA@PDA rose up to 209.85 ± 3.25 mg/g and 240.39 ± 3.26 mg/mg, respectively. By simulating the experimental data with different kinetic models and isotherm models, the adsorption processes of different lignin-derived aerogels were further explored under various conditions. All types of aerogels fit well with the pseudo-second-order model and Langmuir model. In addition, the XPS results confirm that the chemical reduction of Cr(VI) to Cr(III) also plays a role in the removal of Cr(VI). The results demonstrated that the removal effect of lignin-derived aerogels on Cr(VI) was greatly improved through the multi-functionalized surface modification of LGA with PDA and PEI. Furthermore, the removal efficiency of LGA@PDA and LGA@PEI for Cr(VI) remained stable after repeated regeneration. Therefore, the results of this study indicate that LGA@PDA and LGA@PEI are promising Cr(VI) adsorbents for practical applications in wastewater treatment.
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WASTE MANAGEMENT
·
2023
·
IF 8.1
Danni Li,Rui Shan,Jing Gu,Yuyuan Zhang,Xianhai Zeng,Lu Lin,Haoran Yuan,Yong Chen
To relieve the secondary contamination of heavy metals (HMs), the synergistic effect of co-pyrolysis of textile dyeing sludge (DS)/litchi shell (LS) and CaO on the migration of HMs was demonstrated in this study. The proportions of Cu, Zn, Cr, Mn, and Ni in the F4 fraction increased to 75%, 55%, 100%, 50%, and 62% at the suitable CaO dosages. When 10% CaO was added, the RI value of DLC-10% was reduced to 7.89, indicating low environmental risk. The characterizations of the physicochemical properties of biochar provided support for the HMs immobilization mechanism. HMs combined with inorganic minerals or functional groups to form new stable HMs crystalline minerals and complexes to achieve immobilization of HMs. The pH value and pore structure also play an important role in improving the immobilization performance of HMs. In conclusion, the results provided a new direction for the subsequent harmless treatment of HMs-enriched waste.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Zhenmao Chen,Yijing Ai,Weiqiang Yang,Li Niu,Qingxiang Wang,Feng Gao
The unique discriminating ability of hydroxyapatite (HAP) to single- and double-stranded nucleic acid implies its potential as a biosensing material for nucleic acid analysis. Herein, a novel immobilization- and label-free electrochemical strategy has been developed for miRNA let-7a detection based on the specific adsorption of magnetic Fe3O4@hydroxyapatite (Fe3O4@HAP) to a duplex structure. Typically, the highly efficient homogeneous reaction between probe DNA (pDNA) and target miRNA let-7a produces the nucleic acid duplex, which is specifically adsorbed on the surface of Fe3O4@HAP. Thereafter, the electroactive intercalator Nile blue (NB) is introduced as the label-free signal molecule and inserts between the stacked base pairs of the pDNA–miRNA duplex. Thus, the Fe3O4@HAP bearing pDNA–miRNA and numerous intercalated NBs are adsorbed by the magnetic glassy carbon electrode, giving rise to an intense sensing signal without the need of nuclease-assisted cyclic amplification. With this advantage, the sensing system shows a wide linear range from 1.0 fM to 100 nM and a low detection limit of 0.051 fM for miRNA let-7a analysis. What is more, the synergy of the base-pairing-driven hybridization, the specific intercalation of NB to the duplex structure, and the selective adsorption of Fe3O4@HAP contribute to a high sensing specificity of the biosensing strategy. The sensing method provides a state-of-the-art strategy for the sensitive and facile bioanalysis and clinical diagnosis of miRNA.
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Journal of Environmental Sciences
·
2023
·
IF 6.9
Hanbing Meng,Shiwen Hu,Zebin Hong,Wenting Chi,Guojun Chen,Kuan Cheng,Qi Wang,Tongxu Liu,Fangbai Li,Kexue Liu,Yang Yang
Zero-valent iron (ZVI) is a promising material for the remediation of Cd-contaminated paddy soils. However, the effects of ZVI added during flooding or drainage processes on cadmium (Cd) retention remain unclear. Herein, Cd-contaminated paddy soil was incubated for 40 days of flooding and then for 15 days of drainage, and the underlying mechanisms of Cd immobilization coupled with Fe/S/N redox processes were investigated. The addition of ZVI to the flooding process was more conducive to Cd immobilization. Less potential available Cd was detected by adding ZVI before flooding, which may be due to the increase in paddy soil pH and newly formed secondary Fe minerals. Moreover, the reductive dissolution of Fe minerals promoted the release of soil colloids, thereby increasing significantly the surface sites and causing Cd immobilization. Additionally, the addition of ZVI before flooding played a vital role in Cd retention after soil drainage. In contrast, the addition of ZVI in the drainage phase was not conducive to Cd retention, which might be due to the rapid decrease in soil pH that inhibited Cd adsorption and further immobilization on soil surfaces. The findings of this study demonstrated that Cd availability in paddy soil was largely reduced by adding ZVI during the flooding period and provide a novel insight into the mechanisms of ZVI remediation in Cd-contaminated paddy soils.
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CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Xiaowen Zhang,Hong Wen,Qianwen Huang,Yujiao Tan,Zihao Sun,Yilong Hua,Xiaoyan Wu,Mi Li
Developing a materials to realize the selective adsorption and long-term immobilization of uranium is of great significance for the effective remediation of uranium-containing wastewater. Herein, we half-filled Fe 0 into SGB-NH 2 mesoporous channels to prepare a composite of Fe 0 and amino-functionalized silica (Fe 0 @SGB-NH 2 ), and used to the selective removal of uranium in solution under aerobic conditions . It was found that solutions containing 10 mg/L U(VI) could be purified 98.96% by Fe 0 @SGB-NH 2 in the presence or absence of Na + , K + , Mg 2+ , SO 4 2 − , NO 3 − , HCO 3 − and Cl − at pH 5–9. Compared with Fe 0 , its saturation magnetization decreased from 81.24 emu/g to 0.78 emu/g, while the specific surface area increased from 47.895 m 2 /g to 504.404 m 2 /g, successfully preventing the agglomeration and rapid corrosion of Fe 0 without reducing its activity. More interestingly, the consumption of Fe 0 @SGB-NH 2 was only 1/28 of untreated Fe 0 when identical uranium removal efficiency was achieved. Further mechanistic studies indicated that U(VI) was firstly selectively captured by amino groups on the surface of the material and then reduction or adsorption in the pore, the long and narrow mesoporous channels reduce the possibility of uranium re-oxidation, thereby significantly reducing its re-release efficiency from 21.5% to only 1.73%. Encapsulation of Fe 0 within SGB-NH 2 channels was found to facilitate faster removal rate and higher U(VI) reduction ratio, and reduce uranium re-oxidation, thus benefit the long-term immobilization of uranium in contaminated groundwater.
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ENZYME AND MICROBIAL TECHNOLOGY
·
2019
·
IF 3.553
Xuejia Shi,Jin Xu,Changning Lu,Zhenzhong Wang,Wei Xiao,Linguo Zhao
The magnetic particle Fe 3 O 4 -SiO 2 -NH 2 -Cellu-ZIF8 (FSNCZ8) was used to immobilize the high-temperature resistant GH3 β-glucosidase (Tpebgl3) from the Thermomotoga petrophila DSM 13995. The Tpebgl3 has great potential in the catalytic conversion of pharmaceutically active components. The magnetic carrier (FSNCZ8) which provided stronger adsorption capacity, magnetic and high-temperature stability than the previously discussed Fe 3 O 4 -NH 2 -Cellu-ZIF8 without tetraethyl silicate coated. The properties of FSNCZ8-Tpebgl3 (FSNCZ8-T) were as follows: The optimal temperature and pH were 90 °C and 5.5, respectively; the highest activity of FSNCZ8-T approached 2672 U/g; Fe 2+ enabled immobilized enzyme to increase its relative activity to 194%. The main characteristics of FSNCZ8-T, including thermal stability, pH stability, and glucose tolerance, were greatly enhanced by adding Fe 2+ , which was also superior to free enzymes; moreover, the residual activity of FSNCZ8-T was 74% of the initial activity at the end of 10 repeated cycles.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Xiaotong Shen,Miao Yang,Caixia Cui,Hui Cao
In bio-catalysis applications, the non-catalytic properties of immobilized matrices have high importance. In this work, we prepared a sodium alginate/polyacrylamide/hydroxyapatite (SA/PAM/HA) hybrid interpenetrating polymer network (HIPN) hydrogel, which we then proved by SEM and FTIR. The HIPN hydrogel exhibited markedly improved mechanical properties . The compression modulus of the HIPN hydrogel (7.16 MPa) was 14 times higher than that of the interpenetrating polymer network (IPN) hydrogel, with the max storage modulus of the HIPN hydrogel being 31,960 Pa. We then employed an extrusion-based bioprinting (3D printing) technique to carry out a one-pot preparation of the immobilized enzymes. Next, we used different types of immobilized glucose oxidase/catalase to synthesize gluconic acid . There was an increase in the catalytic efficiency with the more porous of the immobilized enzymes. Furthermore, the immobilized enzymes exhibited operational stability. Finally, after reuse in 4 batches, a high conversion of 97% was maintained. These results illustrated that the preparation of one-pot immobilized enzymes by 3D bioprinting has great potential for future application.
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ANALYST
·
2019
·Vol. 144
·期 20
·5971-5979
·
IF 4.019
Zhiqiang Chen,Shuang Liu,Xiaoxiao Yu,Lijie Hao,Li Wang,Shufeng Liu
Alkaline phosphatase (ALP) is an important enzyme related to many clinical diseases and also widely used as a labeling enzyme for immunoassay. Herein, a new electrochemical sensing strategy for ALP activity was proposed, which was based on the ALP-triggered methylene blue (MB) release from a lanthanide coordination polymer and successive penetration through a self-assembled dodecanethiol monolayer for electrochemical response. The supramolecular lanthanide coordination polymer was constructed by using guanine monophosphate (GMP) and Tb3+ as the ligand and the metal ion, respectively, and the encapsulated MB as the signal molecule. ALP catalyzed the cleavage of the phosphate group from the GMP ligand and disrupted the coordination polymer network to release abundant MB molecules for electrochemical responses related to ALP activity. The obtained lanthanide coordination polymers were well characterized by various techniques. The fabricated electrochemical sensor for ALP activity assay shows distinct advantages such as being one-step, label-free, immobilization-free and highly sensitive. The detection limit toward ALP activity was down to 0.5 U L−1. With the aid of a MB enrichment process on the modified electrode before measurement, the detection limit could be further improved to 0.1 U L−1. Moreover, the assay method could be applied for ALP detection in complex matrixes such as human serum and also for efficient inhibitor evaluation. Thus, the current study provides a new pathway to the fabrication of a coordination polymer-based electrochemical sensing platform for applications in disease diagnosis and drug discovery.
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BIOCHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 3.226
Yajie Wang,Qiang Wang,Xiaoping Song,Jingjing Cai
Development of appropriate support for enzyme immobilization with approving loading capacity, stability and recyclable performance is a significant topic in enzyme chemistry . In this study, the hydrophilic polyethylenimine (PEI) modified magnetic graphene oxide (GO) composite (Fe 3 O 4 @ [email protected] ) was fabricated and acted as an efficient solid support for the immobilization of dextranase to improve the stability and recyclable performance. The GO nanosheet component not only provided abundant binding sites for decorating PEI molecules and further increasing the loading capacity of immobilized dextranase, but also acted as a soft matrix for enhancing the stability of immobilized dextranase. In addition, in combination of the unique magnetic separation property, the recyclable ability of immobilized dextranase was further improved. The loading amount of immobilized dextranase on as-developed Fe 3 O 4 @ [email protected] was determined to be 305.1 mg g −1 , which was 1.61 times that on the Fe 3 O 4 @PDA-PEI without GO component. Moreover, the as-developed Fe 3 O 4 @ [email protected] exhibited high immobilization efficiency (76.27%) and enzymatic activity (83.67%), improved stabilities in wide temperature conditions and pH solutions, and excellent reusability (85.78% of its initial activity after 20 cycles). These experimental results suggest that the immobilized dextranase is promising for various applications in biocatalytic engineering fields.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Yue Li,Nanjing Zhong,Ling-Zhi Cheong,Jianrong Huang,Hongxiao Chen,Shaoyan Lin
In this study, SBA-15 was modified by a series of silane coupling reagents and later used to immobilize Candida antartica lipase B (CALB). The enzymatic properties of the immobilized CALB samples were studied. In addition, the catalytic performance in glycerolysis of soybean oil for diacylglycerols (DAG) production was also investigated. The highest enzymatic activity up to 6100.00 ± 246.41 U/g was observed from the propyl methacrylate group modified SBA-15 supported CALB. No loss of activity was observed from the propyl methacrylate group modified SBA-15 supported CALB, but a higher-than-initial activity was notably found from 3-aminopropyl group and n -octyl group modified SBA-15 supported CALB after a 4-h incubation in air at 70 °C. 1-isocyanatopropane group modified SBA-15 supported CALB exhibited selectivity for DAG production. DAG content up to 61.90 ± 2.38 wt% and a DAG/MAG ratio at 3.11 ± 0.08 was obtained after a 24-h reaction at 60 °C in a solvent-free system.
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