RSC Advances
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2019
·Vol. 9
·期 12
·6548-6555
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IF 3.049
Hui Li,Yang Pang,Xin Wang,Xun Cao,Xun He,Kequan Chen,Ganlu Li,Pingkai Ouyang,Weiming Tan
Methods for enhancing enzyme activities in two-phase systems are getting more attention. Phospholipase D (PLD) was successfully encapsulated into metal-surfactant nanocapsules (MSNCs) using a one-pot self-assembly technique in an aqueous solution. The highest yield for the production of high-value phosphatidylserine (PS) from low-value phosphatidylcholine (PC) in the two-phase system was achieved by encapsulating PLD into MSNCs formed from Ca2+ which gave an enzyme activity that was 133.6% of that of free PLD. The PLD@MSNC transformed the two-phase system into an emulsion phase system and improved the organic solvent tolerance, pH and thermal stabilities as well as the storage stability and reusability of the enzyme. Under optimal conditions, PLD@MSNC generated 91.9% PS over 8 h in the two-phase system, while free PLD generated only 77.5%.
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Journal of Zhejiang University-SCIENCE B
·
2018
·
IF 1.815
Yi-ying Zhao,Qiang Chu,Xu-er Shi,Xiao-dong Zheng,Xiao-ting Shen,Yan-zhen Zhang
To address the controversial issue of the toxicity of dental alloys and silver nanoparticles in medical applications, an in vivo-like LO2 3-D model was constructed within polyvinylidene fluoride hollow fiber materials to mimic the microenvironment of liver tissue. The use of microscopy methods and the measurement of liver-specific functions optimized the model for best cell performances and also proved the superiority of the 3-D LO2 model when compared with the traditional monolayer model. Toxicity tests were conducted using the newly constructed model, finding that four dental castings coated with silver nanoparticles were toxic to human hepatocytes after cell viability assays. In general, the toxicity of both the castings and the coated silver nanoparticles aggravated as time increased, yet the nanoparticles attenuated the general toxicity by preventing metal ion release, especially at high concentrations.
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PROCESS BIOCHEMISTRY
·
2017
·
IF 2.497
Wen Qin,Chengjin Wu,Wei Song,Xiulai Chen,Jia Liu,Qiuling Luo,Liming Liu
In this study, an eco-friendly and high-efficient method for the bioconversion of phosphatidylserine (PS) from phosphatidylcholine (PC) and l -serine was developed. After the strain screening, the Streptomyces chromofuscus phospholipase D ( Sc PLD) was chosen and expressed in Escherichia coli BL21 with pET28a (+). After optimization, the maximal specific productivity and Sc PLD hydrolysis activity reached 9049.6 U/g and 10.6 U/mL, respectively, while induction with 2 g/L lactose, at 25 °C for 12 h. The maximal conversions of PC to PS was 93.4% with a final PS concentration of 106.2 g/L (53.1 g/L/h) under theoptimal conditions: 0.153 M PC in CPME, 2.3 M l-ser in sodium acetate buffer, 2.0 g lyophilized cells/mol PC, 100 mM Ca 2+ , 40 °C, and 2 h of incubation. After scale-up to 1 L, the conversions and yield maintained at 85.4% and 97.2 g/L. Therefore, the enzymatic process showed great potential for industrialization of PS.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
·
IF 8.1
Fang Li,Haili Lin,Huiqin Yu,Xuemei Jia,Shifu Chen,Jing Cao
Replacing the sluggish oxygen evolution reaction with the oxidation of benzyl alcohol to construct the hybrid water electrolysis system has been attractive for its merits of environmentally friendly and economically efficient. However, the activity of the catalyst to oxidize alcohols needs to be further improved. Tailoring the d-band center (E d ) has been proven as an effective method to promote the hydrogen evolution reaction (HER). How feasible is this strategy in the oxidation of benzyl alcohol? Here, using Co 2 C as a research platform, the doping nonmetal heteroatom (P, S, N) engineering is adopted to promote its electrocatalytic BA oxidation and HER performance. The results of electrochemical tests show that the P-doped Co 2 C (P–Co 2 C) only requires a low potential of 1.33 and 1.38 V vs. RHE to achieve current densities of 20 and 100 mA cm −2 for BA oxidation, which is superior to that of S–Co 2 C, N–Co 2 C, and pristine Co 2 C. The conversation and faradaic efficiency for BA is up to 98.1% and 93.8% during ten consecutive cycle tests. The P–Co 2 C also exhibited outstanding activity and stability toward HER. The density functional theory (DFT) calculation revealed that specified P doping could modify the d-band center of Co 2 C approaching the peak of the volcano map (electrochemical overpotentials ∼ E d ). The Gibbs free energy of the BA oxidation was also reduced, thus optimizing the adsorption and desorption process of intermediates. On the other hand, the catalyst surface physical properties of Co 2 C such as hydrophilicity was promoted by the doped heteroatoms which was favorable for the gas-liquid-solid triphase electrocatalytic reaction. This work offers a facial perception of regulating the d-band to design advanced bifunctional electrocatalysts for organic matter oxidation and HER.
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ChemSusChem
·
2016
·Vol. 9
·期 10
·1118-1124
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IF 7.116
Xuefeng Liu,Zipeng Xing,Hang Zhang,Wenmei Wang,Yan Zhang,Zhenzi Li,Xiaoyan Wu,Xiujuan Yu,Wei Zhou
Graphical Pass the Mo : A 3 D sandwich of mesoporous black TiO 2 (MBT)/MoS 2 /MBT was fabricated using a facile mechanochemistry method combined with an in situ solid-state chemical reduction approach. The material exhibited excellent visible-light-driven photocatalytic performance for pollutant degradation and hydrogen evolution owing to the sandwich-like heterojunction structure and Ti 3+ doping. A novel 3 D mesoporous black TiO 2 (MBT)/MoS 2 /MBT sandwich-like nanosheet was successfully fabricated using a facile mechanochemical process combined with an in situ solid-state chemical reduction approach, followed by mild calcination (350 °C) under an argon atmosphere. The MBT/MoS 2 /MBT exhibits a 3 D sandwich-like nanosheet structure and heterojunctions are formed at the interfaces between MoS 2 and black TiO 2 . The significantly narrowed band gap of MBT/MoS 2 /MBT is attributed to the introduction of MoS 2 and the formed Ti 3+ species in the frameworks. The visible-light photocatalytic degradation rate of methyl orange and the hydrogen production rate are as high as 89.86 % and 0.56 mmol h −1 g −1 , respectively. The introduction of MoS 2 and Ti 3+ in the frameworks favors the visible-light absorption and the separation of photogenerated charges, and the 3 D sandwich-like heterojunction structure facilitates the transfer of photogenerated charges.
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RSC Advances
·
2016
·Vol. 6
·期 111
·109992-110000
·
IF 3.289
Zhiyong Zhou,Ke Cui,Yu Mao,Wenshuai Chai,Nian Wang,Zhongqi Ren
Enantioseparation of chiral compounds is important for pharmaceutical production. Chiral resolution of racemic tryptophan has attracted increasing attention. Traditional separation methods have the disadvantages of being high cost, energy intensive and environmentally unfriendly. Membrane permeation seems promising for application in the enantioseparation of racemic tryptophan with the advantages of energy efficiency and no additives. However, lots of organic compounds are commonly used for the preparation of various membranes for enantioseparation of racemic tryptophan. Therefore, we prepared a molecularly imprinted self-supported membrane (MISM) using a green and clean method with natural polymer sodium alginate (SA) as the functional polymer, water as the solvent and CaCl2 as the crosslinking agent. The crosslinking by CaCl2 was confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analyses. The surface and internal structures of the MISM and non-imprinted self-supported membrane (NISM) were observed by atomic force microscope (AFM) and scanning electron microscope (SEM). The addition of a template molecule can significantly improve the MISM surface roughness. The compact structures of MISM and NISM were confirmed by the cross-sectional images. The thermo stability of MISM was studied. In addition, the effects of pH and crosslinking time on the swelling behavior of MISM were investigated. A high concentration of OH− in alkali solution can remarkably weaken the electrostatic interaction between Ca2+ and COO−. The effects of preparation conditions, permeation conditions and concentration polarization on the pressure-driven permeation performance of MISM were investigated. Ultrahigh enantioseparation performance in 99% ee of the permeation solution can be obtained under mild conditions. Reducing the concentration polarization by increasing the environmental temperature and continuous stirring is beneficial to obtaining ultrahigh ee. Comparison with previous studies on pressure-driven permeation performance indicates that the proposed green and clean preparation method for a molecularly imprinted self-supported membrane is not only environmentally friendly but also efficient in obtaining ultrahigh ee.
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POLYMER ENGINEERING AND SCIENCE
·
2017
·Vol. 57
·期 11
·1252-1261
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IF 1.449
Yuan Zong,Hao Tang,Ling Zhao
Poly(p-phenylene terephthalamide) (PPTA) is a typical high-performance fiber and usually synthesized by low temperature solution polycondensation in twin screw extruder. During the reactive extrusion, flow behavior, rheokinetics, and temperature are highly coupled, which makes it difficult to ensure the quality of product. In the present work, the rheokinetics of the PPTA solution is established by experiments and its reactive extrusion is investigated via 3-D numerical simulation. The flow pattern, molecular weight distribution and temperature have been investigated for the extruders with three different elements, i.e., full flight screw (FF), kneading block (KB), and screw mixing element (SME). The results indicate that the unique flow characteristic of different screw elements affects mixing experience of the reactants and further the PPTA qualities. By numerical simulation, it shows the temperature increase within the tested extrusion stage is 7 K and reaction heat is found the main energy source for extrusion stage. Furthermore, heat removal method is verified with consideration of industrial production process. The numerical simulation work also discusses the reaction and mixing process in the extruders with three combined screws. The results show the introduction of more reverse FF and KB elements can lead to higher quality of PPTA. POLYM. ENG. SCI., 57:1252–1261, 2017. © 2017 Society of Plastics Engineers
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CHINESE JOURNAL OF CATALYSIS
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2016
·
IF 2.628
Yilong Wang,Yun Zhang,Aijun Sun,Yunfeng Hu
A novel marine microbial esterase PHE14 was cloned from the genome of Pseudomonas oryzihabitans HUP022 isolated from the deep sea of the western Pacific Ocean. Esterase PHE14 exhibited very good tolerance to most organic solvents, surfactants and metal ions tested, thus making it a good esterase candidate for organic synthesis that requires an organic solvent, surfactants or metal ions. Esterase PHE14 was utilized as a biocatalyst in the asymmetric synthesis of D-methyl lactate by enzymatic kinetic resolution. D-methyl lactate is a key chiral chemical. Contrary to some previous reports, the addition of an organic solvent and surfactants in the enzymatic reaction did not have a beneficial effect on the kinetic resolution catalyzed by esterase PHE14. Our study is the first report on the preparation of the enantiomerically enriched product D-methyl lactate by enzymatic kinetic resolution. The desired enantiomerically enriched product D-methyl lactate was obtained with a high enantiomeric excess of 99% and yield of 88.7% after process optimization. The deep sea microbial esterase PHE14 is a green biocatalyst with very good potential in asymmetric synthesis in industry and can replace the traditional organic synthesis that causes pollution to the environment.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2014
·
IF 3.107
Mohamed Reda Zahi,Pingyu Wan,Hao Liang,Qipeng Yuan
d-Limonene organogel-based nanoemulsion was prepared by high-pressure homogenization technology. The organogelator type had a major role on the formation of the formulations, in which stearic acid has given nanoemulsions with the smallest droplet size. The surfactant type and concentration also had an appreciable effect on droplet formation, with Tween 80 giving a mean droplet diameter (d ≈ 112 nm) among a range of non-ionic surfactants (Tween 20, 40, 60, 80, and 85). In addition, high-pressure homogenization conditions played a key role in the nanoemulsion preparation. The stability of d-limonene organogel-based nanoemulsion was also investigated under two different temperatures (4 and 28 °C) through 2 weeks of storage. Results showed a good stability of the formulations, which is maybe due to the incorporation of d-limonene into the organogel prior to homogenization. This study may have a valuable contribution for the design and use of organogel-based nanoemulsion as a delivery system in food.
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MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 11
·1407-1413
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IF 3.719
Liu Cunwei,Li Baoxin,Xu Chunli
We report on a method for visual differentiation between the D- and L-forms of tryptophan (Trp). It is based on the inherent chirality of citrate-capped silver nanoparticles (AgNPs; ca. 15 nm in diameter) that can be used as chiral selector for D- and L-forms of Trp. On addition of D-Trp to a solution of the AgNPs, a color change from yellow to red can be seen, while no color change is found on addition of L-Trp. The chiral assay can be used to determine the enantiometric excess of D-Trp in the range from −50 % to 100 %. The effect can be detected with bare eyes and quantified by spectrophotometry. Notably, this method does not require any labeling or chiral modification. The method excels by its sensitivity, low cost, good availability of materials, and its simplicity.
The silver nanoparticles can discriminate the absolute configuration of Trp and determine the enantiomeric excess of Trp
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Journal of Materials Chemistry A
·
2024
·Vol. 12
·期 45
·31518-31525
·
IF 10.7
Qiyan Sun,Yu Miao,Ruixue Zhang,Guang-Rui Xu,Chuanfang Zhang,Kang Liu,Zexing Wu,Lei Wang
Water electrooxidation in proton exchange membrane (PEM) water electrolyzers has been considered to be a four-electron pathway mechanism, which leads to inherent sluggish kinetics that severely limits the scalable production of high-purity H2. Herein, cobalt phosphide/iron phosphide (Co2P/FeP) nanosheets with electron redistribution through aerogel-assisted and gas-phase phosphorization strategies have been reported. Benefiting from the unique nanosheet structure and electron redistribution induced by p–d hybridization interaction, the as-obtained Co2P/FeP nanosheets display outstanding alkaline oxygen evolution reaction (OER) performance. Co–P and Fe–P charge bridges trigger p–d orbital hybridization between the transition metal and P elements, which downshifts the d-band center of Co2P/FeP nanosheets and accelerates the formation of *OOH with a lower energy barrier that can expedite the water electrooxidation process with an overpotential of 257 mV to reach the 10 mA cm−2 current density and a Tafel slope of 39.6 mV dec−1. This work provides a deep insight into understanding the remarkable OER properties of transition metal phosphates by electron redistribution.
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Radiation Effects and Defects in Solids
·
2024
·
IF 1.1
X.L. Ren,G. Yao,L.M. Luo,Y. Xu,A. Yabuuchi,Q. Xu
In the present study, we developed Mo- and Zr-added W-Y2O3 composites, and investigated their surface damage, including commercially available W induced by He and D as well as He and D mixture plasmas. Blistering was not observed in the D-plasma-irradiated W and W composites. The thickness of the damaged surface layer due to He plasma exposure of the W-Mo-Y2O3 composite was similar to that of W. However, the thickness of the damaged surface layer of the W-Y2O3 composite was half that of W. In addition, the thickness of the damaged surface layer of the W-Zr-Y2O3 composite was further improved by 5 times. Y2O3 nanoparticles, especially refined Zr-Y-O nanoparticles, act as He trap sites to suppress the formation and growth of He bubbles. Furthermore, the W-O-Y and W-O-Zr-Y nanoparticles increased the solubility of He and delayed He diffusion, hindering the formation of He bubbles.
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