Frontiers in Bioengineering and Biotechnology
·
2020
·
IF 3.644
Peng Fei,Su Hui-Hui,Ou Xiao-Yang,Ni Zi-Fu,Zong Min-Hua,Lou Wen-Yong
(R)-1-phenyl-1,2-ethanediol is an important synthon for the preparation of β-adrenergic blocking agents. This study identified a (2R,3R)-butanediol dehydrogenase (KgBDH) from Kurthia gibsonii SC0312, which showed high enantioselectivity for production of (R)-1-phenyl-1,2-ethanediol by reduction of 2-hydroxyacetophenone. KgBDH was expressed in a recombinant engineered strain, purified, and characterized. It showed good catalytic activity at pH 6–8 and better stability in alkaline (pH 7.5–8) than an acidic environment (pH 6.0–7.0), providing approximately 73 and 88% of residual activity after 96 h at pH 7.5 and 8.0, respectively. The maximum catalytic activity was obtained at 45°C; nevertheless, poor thermal stability was observed at >30°C. Additionally, the examined metal ions did not activate the catalytic activity of KgBDH. A recombinant Escherichia coli strain coexpressing KgBDH and glucose dehydrogenase (GHD) was constructed and immobilized via entrapment with a mixture of activated carbon and calcium alginate via entrapment. The immobilized cells had 1.8-fold higher catalytic activity than that of cells immobilized by calcium alginate alone. The maximum catalytic activity of the immobilized cells was achieved at pH 7.5, and favorable pH stability was observed at pH 6.0–9.0. Moreover, the immobilized cells showed favorable thermal stability at 25–30°C and better operational stability than free cells, retaining approximately 55% of the initial catalytic activity after four cycles. Finally, 81% yields (195 mM product) and >99% enantiomeric excess (ee) of (R)-1-phenyl-1,2-ethanediol were produced within 12 h through a fed-batch strategy with the immobilized cells (25 mg/ml wet cells) at 35°C and 180 rpm, with a productivity of approximately 54 g/L per day.
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CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Jiayi Song,Wenting He,Hao Shen,Zixin Zhou,Mengqi Li,Ping Su,Yi Yang
The enzymatic activity and practical applications of immobilized enzymes were severely influenced by their location orientation and microenvironment, which played the key roles in maintaining the active conformation and accelerating the reaction process of the desired enzymes. Herein, we presented a general approach to prepare magnetic DNA nanocompartments for encapsulation of metabolic model cascade multi-enzymes, glucose oxidase (GOx) and horseradish peroxidase (HRP), through self-assembly. The enzymes were spatially confined in the well-designed DNA compartments, which were located at the gap areas of magnetic particles. Systematic studies indicated the proximity effect of the multi-enzymes and the high negative charge density microenvironment of the DNA compartments contributed to the high cascade activity together. In addition, the immobilization enzymes within magnetic DNA compartment remarkably increased the overall catalytic efficiency, operational stability, and reusability. The k cat of encapsulation multi-enzymes was 204 s −1 , which was 16.6-fold higher than that of free enzymes. The immobilized enzymes were further applied for on-line visual detection of glucose with excellent selectivity , and the immobilized enzymes also showed relative high cytotoxicity towards Hela cells, demonstrating their promising prospect for biocatalysis and cancer starvation therapy.
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ENVIRONMENTAL MANAGEMENT
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2020
·Vol. 65
·期 6
·818-828
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IF 2.561
Zhou Changrui,Yuan Haiyan,Ning Chuanchuan,Li Shuailin,Xia Zhuqing,Zhu Mengmeng,Ma Qiang,Yu Wantai
Using amendments is a cost-effective method to soil cadmium (Cd) remediation, whereas knowledge about how different amendments and rates affect remediation efficiency remains limited. This study aimed to evaluate the impacts of different types and amounts of amendments on soil Cd immobilization and its uptake by plants. Biochar (BC), zeolite (ZE), humic acid (HA), superphosphate (SP), lime (L), and sodium sulfide (SS) were applied at three rates (low, medium, and high) ranging from 0.5 to 5%. The concentration of CaCl 2 -extractable Cd was considerably affected by the amendments, except HA, and the high doses achieved better immobilization effects than the low doses did. The addition of amendments decreased weak acid soluble Cd by 4.1–44.0% but slightly increased the fractions of oxidizable and residual Cd. These amendments (except BC and HA dose of 1%) decreased Cd accumulation in grains by 1.3–68.8% and (except SP) in roots by 16.3–65.5% compared with the control. The SP efficiently immobilized Cd but posed a potential soil acidification risk. Moreover, SS treatment increased the soil electrical conductivity (EC) value and restricted the growth of wheat, possibly due to high-salt stress. BC, ZE, and L exerted significant effects on the reduction in available Cd as the application rate increased. These amendments enhanced Cd immobilization mainly by changing Cd availability in soil and influencing its redistribution in different fractions in soil and root uptake by plants. This study concluded that BC-5%, ZE-1%, and L-0.5% can be used for Cd immobilization in acidic or neutral soils.
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2020
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IF 9.038
Jin Chen,Mingzhu Jiang,Jing Chen,Wenjian Xu,Hongpeng Jia
Selective immobilization of single-atom Au on the specific facets of CeO 2 has been successfully performed by redox etching precipitation (REP), which makes it possible to clearly refine the interfacial effect of multiple-facet support on single atom . With systemic characterizations, it is found that single-atom Au is apt to lie on nonpolar facets of CeO 2 (111) and (110) rather than polar facet of CeO 2 (100). The modification of morphology-dependent properties is attributed to the different interaction between Au atom and each CeO 2 interface. Because of synergy between Au and CeO 2 , more oxygen vacancies and more active oxygen species are generated; meanwhile, the interfacial effect stabilizes the charged Au species which serves as active site. Therefore, the performance in catalytic oxidation of HCHO and CO on CeO 2 is facilitated by loading Au. Among them, CeO 2 rod-supported Au as an optimal catalyst exhibits a remarkable activity and stability. With in-situ characterization, the reaction mechanisms for HCHO and CO oxidation over Au/r-CeO 2 are studied. Meanwhile, it is proved that REP strategy is also valid to obviously promote catalytic performance whenever commercial CeO 2 is used or Au is replaced with Ag, so the improvement of recently applied catalyst with REP process is promising.
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MATERIALS CHEMISTRY AND PHYSICS
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2020
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IF 3.408
Ruimin Hu,Tao Fan,Jinlong Yang,Hang Xiao,Yiping Liu,Ming Lu
Recent years have witnessed the explosive progress of functional nano materials in textile field, requires us to re-recognize and understand the potential hazards of nanoparticles . A harmless, cost-effective and facile approach of growing functional particles with special morphology and immobilizing onto cellulose fabric (CF) to prepare functional fabrics is highly desired. Here, commercial TiO 2 nanoparticles (TiO 2 NPs) grow under ultrasound-microwave and form a flake-like structure, which retain excellent photocatalytic degradation ability and prevented the potential harm to human body when nanoparticles fell off. The method was implemented based on 4-methylmorpholine-N-oxide (NMMO) aqueous system which was approved as a favorable solvent for dissolving cellulose, and grew flake-TiO 2 on cotton fibers under the assistance of the ultrasound and microwave. The as-prepared TiO 2 -CF possessed satisfactory photocatalytic activity for Methylene blue (MB) and Rhodamine B (RhB) dyes under ultraviolet light with the low dye residue rate of about 5% and 1%, respectively. After 50 times rigorous washing procedures, the titania loading next to 18% was confirmed by thermogravimetric analysis , which proved that TiO 2 -CF had good wash fastness.
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ELECTROPHORESIS
·
2020
·
IF 3.081
Mengqi Li,Hao Shen,Zixin Zhou,Wenting He,Ping Su,Jiayi Song,Yi Yang
In recent years, CE-integrated immobilized enzyme reactors (IMERs) for single-enzyme immobilization have attracted considerable attention. However, there has been little research on multienzyme immobilization in CE. Here, we introduce a method for fabricating a CE-integrated IMER, using DNA-directed immobilization to fix glucose oxidase and horseradish peroxidase in the capillary, which had been functionalized with polyamidoamine dendrimer (PAMAM). Owing to the reversibility of DNA hybridization, the reactor is capable of dynamic immobilization. Moreover, by introducing the PAMAM, the loading capacity of the IMER is greatly enhanced, and the PAMAM can spontaneously form complexes with DNA and then contribute to the efficiency and stability of the reactor. After 25 days storage, the prepared IMER ultimately retained approximately 70% of its initial activity. We also used the IMER to detect glucose, and the favorable linearity was obtained over the concentration range of 0.78–12.5 mM, with an LOD of 0.39 mM, demonstrating that the CE-integrated IMER can be applied to actual samples. We believe that this strategy can be extended to other multienzyme immobilization systems, and CE-integrated IMERs are potentially useful in a wide range of biochemical research applications.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
·
IF 5.162
Fei Peng,Xiao-Yang Ou,Ze-Wang Guo,Ying-Jie Zeng,Min-Hua Zong,Wen-Yong Lou
Artificial multienzyme biocatalysts have played a crucial role in biosynthesis because they allow for conducting complex reactions. Here, we reorted a facile approach to fabricate multienzyme nanodevices with high catalytic activity and stability based on protein assembly and chemical crosslinking. The self-assembled partner SpyCatcher and SpyTag were genetically fused with 2,3-butanediol hydrogenase and formate hydrogenase to produce Kg BDH-SC (SpyCatcher-fused 2,3-butanediol hydrogenase) and FDH-ST (SpyTag-fused formate hydrogenase), respectively. After assembling the two fusion proteins, the complexes were then immobilized on the functionalized silicon dioxide nanoparticles by glutaraldehyde, forming Kg BDH-SC-ST-FDH-SiO 2 with the capability of reducing 2-hydroxyacetophenone to ( R )-1-phenyl-1,2-ethanediol with cofactor regeneration. Under the optimal conditions, the created co-immobilized enzymes performed 49% activity recovery compared with the mixture of free enzymes as well as showed 2.9-fold higher catalytic activity than the traditional random co-immobilized enzymes. Moreover, Kg BDH-SC-ST-FDH-SiO 2 showed better pH stability and organic solvents stability than the free enzymes, and remained 52.5% overall catalytic activity after 8 cycles. Finally, the co-immobilized enzymes can reduce 60 mM HAP for fabrication of ( R )-PED with cofactor regeneration in the phosphate buffer reaction system, affording 83.9% yield and above 99% optical purity.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 27
·期 2
·1888-1897
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IF 2.914
Wang Ying,Wang Luxing,Deng Xiaoyan,Gao Hongtao
Waste biomass can be recycled to prepare biochar for soil restoration, in which process soil fertility would not be lost. In this work, biochar was prepared from waste pomelo peel, combined with ZnO, to be used to immobilize Cu(II) in contaminated soil, whose maximum adsorption capacity was up to 216.37 mg g −1 . Due to combination of ZnO, the BET surface area of biochar increased from 2.39 to 18.53 m 2 g −1 . Meanwhile, the surface functional groups increased, which was conducive to fixation of metal ion on the surface of biochar. Both pseudo-second-order kinetics and Langmuir isotherm model fit the experimental data well. Adsorption was easy to happen since the adsorption site on the surface of biochar/ZnO had a strong affinity with Cu(II). In addition, mechanism investigation indicated that Cu(II) was bond with biochar/ZnO mainly by non-bioavailable state (75.6%) primarily. It inferred that biochar/ZnO was an efficient and promising passivator in reducing heavy metal risk in soil.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2023
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IF 8.2
Tong Qin,Liqin Liu,Haibing Cao,Bin Lu,Shuangxi Nie,Zhengbai Cheng,Xiaohong Zhang,Hongbin Liu,Xingye An
Herein, a green facile approach to improve the flexibility of unbleached bamboo kraft pulp (UBKP) via an immobilized enzyme technology is proposed. Polydopamine (PDA) acts as versatile modification and coating materials of cellulose nanocrystals (CNC) for assembling versatile bio-carriers (PDA@CNC). Cellulase biomacromolecules are efficiently immobilized on PDA@CNC to form cellulase@PDA@CNC nanocomposites. The relative enzyme activity , temperature/pH tolerance, and storage stability of cellulase were significantly improved after immobilization. The degree of polymerization treated UBKP decreased by 5.42 % (25 U/g pulp) compared to the control sample. The flexibility of treated fibers was 6.61 × 10 14 /(N·m 2 ), which was 96.93 % higher (25 U/g) compared to the control and 3.88 times higher than that of the blank fibers. Cellulase@PDA@CNC performs excellent accessibility to fiber structure and induces high degree of fibrillation and hydrolysis of UBKP fibers, which contributes high softness of obtained tissue handsheets. The bio-carrier PDA@CNC within paper framework may further enhance tissue tensile strength . This study proposes a practical and environmentally friendly immobilization approach of cellulase@PDA@CNC for improving the hydrolysis efficiency and flexibility of UBKP fibers, which provides the possibility to maintain the strength of tissue paper while improving its softness, thus broadening the high-value application of immobilized enzyme technology in tissue production.
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NEW JOURNAL OF CHEMISTRY
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2017
·Vol. 41
·期 14
·6089-6097
·
IF 3.269
Jiayi Song,Ping Su,Ye Yang,Yi Yang
Enzymes usually have poor thermal and operational stability as well as limited reuse cycles, which greatly limit their practical applications. This study reports a novel strategy for enzyme immobilization based on toehold-mediated DNA strand displacement on modified magnetic nanoparticles using alkaline phosphatase (ALP) and horseradish peroxidase (HRP) as different model enzymes. The immobilized enzyme procedure by DNA strand displacement exhibited high reversibility and reproducibility, and the mild, convenient approach achieved successive enzyme immobilization through triggering a toehold-mediated DNA strand displacement reaction. The immobilized HRP exhibited promising thermal stability after 50 min incubation at 50 °C and 60 °C, which were about 6.5- and 9.7-fold greater than the free enzyme, respectively. Notably, the immobilized enzyme exhibited excellent long-term storage stability, and the enzymatic activities were about 34.4- and 24.9-fold greater than free HRP after storage at 4 °C for 68 days and at room temperature for 9 days, respectively. The immobilized enzyme also preserved high performance towards long-term incubation stability, compared to the free enzyme, and excellent reusability, which showed a high degree of activity (more than 73%) after 5 cycles. Thus, the developed strategy exhibited a promising alternative platform with high magnetic responsiveness and significantly enhanced properties for the immobilization of important enzymes and their broad applications.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Hao Zhou,Yongheng Shi,Lingmei Dai,Dehua Liu,Wei Du
Pyrolyzing ZIF-8 into N-doped carbon is now inspiring new potential of ZIF-8 for extensive applications. However, the exploration of such ZIF-8-derived carbon for biotechnological applications has been rarely investigated, especially in this context that imidazole derivatives are of rich functionality in life science. Herein, we reported a facile temperature-dependent pyrolysis method to achieve the effective N-doping in ZIF-8-derived macroporous carbon, which was systematically investigated for the immobilization of lipase from Thermomyces lanuginosus (TLL) in biodiesel production. MNC-600 (macroporous N-doped carbon derived at 600 °C) exhibited the best immobilization performance, with the highest specific activity of 190.6 U mg −1 , a 36.9% increase than free TLL. Moreover, MNC-600@TLL showed superior effectiveness and robustness in biodiesel production. A much faster rate of conversion and the highest biodiesel yield of 87.4% were observed. After eight successive batches of recycling, MNC-600@TLL retained 93.4% of its initial activity. XPS analysis revealed the evolution of N species during the pyrolysis of ZIF-8. It was proposed that the abundant doping of pyrrolic N species played a major role in the surprising performance of MNC-600, mainly through hydrogen bonding interactions, which simultaneously realized the activation of reactants as well as the in-situ hydrophobization of biocatalyst. This report is anticipated to pave a way for the exploration of ZIF-8-derived N-doped carbon for extensive biotechnological applications.
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INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Qiufeng Deng,Rui Zhai,Baohua Chen,Xiaoxiao Jiang,Haixiang Li,Chen Li,Mingjie Jin
Developing value-added lignin-based biomaterials for enzyme immobilization has drawn great attention. This study developed a cost-effective and eco-friendly one-pot strategy to synthesize the rod-like lignin@zeolitic imidazolate framework-8 (ZIF-8) hybrid nanomaterial by using lignin derived from lignocellulosic biofuel production. The incorporation of lignin into the ZIF-8 network not only altered the morphology, but also modified the surface properties of the material, making it an ideal support for enzyme immobilization. The synthesized nanoscale hybrid materials were used to immobilize beta-glucosidase (BG) with high immobilization capacity and about 92–166 mg/g of BG was immobilized through physical adsorption. The immobilized BG exhibited good stability, catalytic activity and recycling properties, and was reused under acidic conditions for more than 8 cycles with more than 60% activity kept. The as-prepared hybrid material can serve as a great carrier for immobilizing various biomolecules.
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