WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
·
2025
·Vol. 41
·期 3
·1-11
·
IF 4.2
Liu Ming-Yu,Wang Yu-Yue,Li Han-Zhi,Luo Xue-Mei,Feng Jia-Xun,Zhao Shuai
Nitriles exhibit acute cytotoxicity to human and animal cells. Nitrilase is a green biocatalyst that can directly convert nitrile into nontoxic carboxylic acids and ammonia. However, the nitrilases capable of degrading 3-butenenitrile and 4-pentenenitrile derived from glucosinolate present in rapeseed meals are still limited. This study expressed the nit rilase 2 gene from bacterium Paraburkholderia g raminis ( PgNIT2 ) in Escherichia coli . The purified recombinant nitrilase rPgNIT2 showed specific activities of 5.94 U/mg and 6.66 U/mg when using 3-butenenitrile and 4-pentenenitrile as substrates at the optimal pH 7.0 and temperature 45 °C. The substrate binding pocket of PgNIT2 comprising 12 amino acids was required for rPgNIT2 activity. Remarkably, the specific activity of mutant enzyme A190I increased by 68.3% and 57.3%, respectively, against 3-butenenitrile and 4-pentenenitrile compared with the wild-type enzyme. Furthermore, the A190I showed improved thermostability and hydrolysis ability towards 3-butenenitrile and 4-pentenenitrile compared with rPgNIT2 but shared the same optimal pH and temperature. These results provided theoretical guidance for engineering of bacterial nitrilases used for rapeseed meal detoxification.
研究领域:
生物化学
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分子生物学
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DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 72
·58393-58402
·
IF 3.84
Yuanyuan Xu,Jinming Sun,Hou Chen,Liangjiu Bai
This study describes reversible addition–fragmentation chain-transfer (RAFT) polymerization initiated by cobalt(III) acetylacetonate (Co(acac)3). With Co(acac)3 as the initiator, RAFT polymerization of acrylonitrile was achieved at 90 °C mediated by 2-cyanoprop-2-yl dithionaphthalenoate. The polymerization exhibited “living”/controlled characteristics with a molar mass distribution as low as 1.25. Homogeneous polyacrylonitrile nanofibers (PAN-nFs) were produced via the electrospinning technique. FTIR, SEM and TGA analyses revealed aminated-PAN-nFs (APAN-nFs) were successfully obtained via ethylenediamine grafting onto the surface of PAN-nFs. The adsorption interaction between methyl orange (MO) dye and APAN-nFs is discussed in detail. The maximum saturation adsorption capacity was 102 mg g−1. The adsorption kinetics followed a pseudo-second-order model. The Langmuir model was better for interpreting the isothermal process for MO and APAN-nFs. The Dubinin–Radushkevich isothermal model indicated that the adsorption proceeded chemically. Intraparticle diffusion was not the only rate-limiting step. The thermodynamics properties indicated the adsorption process was exothermic and spontaneous in nature. The MO dye adsorbed by APAN-nFs could be reversibly desorbed by an aqueous solution of pH = 1. APAN-nFs could be recycled efficiently.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2011
·Vol. 49
·期 22
·4721-4724
·
IF 3.894
Hou Chen,Min Zhang,Mengmeng Yu,Hongyan Jiang
Graphical Iron tube was applied as catalyst source in the design of continuous SET-LRP of AN without any ligand using BPN as initiator in NMP and DMF, respectively. First-order kinetics of polymerization with respect to the monomer concentration, linear increase of the molecular weight, and narrow polydispersity with monomer conversion showed the controlled radical polymerization characters. An increase in polymerization rate in NMP was observed compared with in DMF. The living feature of PAN was verified by chain extensions of PAN with MMA.
研究领域:
化学工程
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高分子科学
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产品关联
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Yuhang Jiao,Huijie Yan,Qingxin Meng,Shiling Jia,Shuang Liu,Huixuan Zhang,Zhongyu Fu
For the first time, a new polymerization medium, dimethyl carbonate (DMC), was used for the polymerization of acrylonitrile (AN), and polyacrylonitrile (PAN) powder was obtained successfully. The effects of polymerization factors, including monomer concentrations, temperature and initiator concentrations on the structures and properties of PAN powders were investigated by nuclear magnetic resonance spectroscopy (NMR), total internal reflectance Fourier transform infrared spectrometer (FTIR), wide-angle X-ray diffractometer (WXRD) and thermal gravimetric analyzer (TGA). The polymerization kinetic and mechanistic study of PAN with DMC as the polymerization medium were discussed in details. There are three key achievements in this paper. First, the kinetic equation of PAN polymerization with DMC as a medium was established: R p = K [ ABVN ] 0.92 [ AN ] 6.78 . This result shows that the R p is highly dependent on the AN concentrations. Second, the chain transfer constant of DMC was measured to be 4.57 × 10 −4 at 60 °C, and the chain transfer constant increases with polymerization temperature. Lastly, the structures and properties of PAN powders prepared with H 2 O, tetrahydrofuran (THF) and DMC as media were compared. The results showed that the PAN prepared with DMC as a medium by free radical polymerization had a higher conversion, molecular weight and better crystalline property compared to THF. These findings indicate that DMC is a promising medium for manufacturing high quality PAN powder by free radical polymerization.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
Molecular Catalysis
·
2020
·
IF 3.687
Kaikai Liu,Tiefeng Wang,Minghan Han
The catalytic isomerization of 2-methyl-3-butenenitrile (2M3BN), a model reaction in the DuPont process, has been performed using NiL 4 (L=tri- O - p -tolyl phosphite) as a catalyst. The lowered catalytic activity in the isomerization with coexistence of 2-pentenenitrile (2PN) and 2-methyl-2-butenenitrile (2M2BN) indicates that both 2PN and 2M2BN are the catalyst inhibitors , and the quantitative relationship between the conversion of 2M3BN and the content of 2M2BN and 2PN is provided. DFT calculation results suggest that the inhibition effect is attributed to the generation of dead-end intermediates (2PN)NiL 2 and (2M2BN)NiL 2 , both of which take nickel atom out of the catalytic cycle in the isomerization process. To suppress the inhibition effect, new catalytic intermediates are rationally designed based on their computational %V bur . An efficient method that adding extra ligand 1, 5-bis(diphenylphosphino)pentane (dppp5) to the NiL 4 catalyst is selected experimentally. Compared to the results obtained with NiL 4 as catalyst, the (dppp5)NiL 2 increases the conversion of 2M3BN from 74.5 % to 93.4 % at 3 h of reaction and provides a high selectivity to 3PN (> 98 %) at optimal conditions.
研究领域:
催化
·
有机化学
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计算化学
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DOI
高影响因子
DESIGNED MONOMERS AND POLYMERS
·
2017
·
IF 1.139
Yazhen Wang,Yutao Di,Shaobo Dong,Zijian He,Xueze Zhang,Jia Shi,Tianyu Lan
(3-(tert-butylperoxy)propyl) trimethoxysilane (TBPT), is a tailor-made new style silane coupling agent with peroxide group, which have ability of initiating polymerization. This study used TBPT to generate free radical, and initiated the polymerization of acrylonitrile (AN), thereby forming polyacrylonitrile (PAN) in two approaches, thermal initiation system and redox initiation system. Meanwhile this study bonded TBPT onto nano-TiO2 to get modified nano-TiO2 by means of the coupling function of TBPT, and then made the peroxide group of the modified nano-TiO2 decompose and initiate the polymerization of AN in thermal initiation system and redox initiation system respectively. The products were investigated and analyzed by FTIR, XPS and TG. The result showed that on one hand, in the products of the thermal initiation there was PAN, which both attached and unattached to the modified nano-TiO2; on the other hand, in the products of the redox initiation system the PAN unattached to the modified nano-TiO2 was produced, while the PAN attached to the modified nano-TiO2 was not.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
PubMed
高影响因子
ADVANCES IN POLYMER TECHNOLOGY
·
2021
·
IF 2.389
Yuanying Zhang,Xuechun Zhang,Yongbin Cao,Jiachun Feng,Wuli Yang
Herein, acrylonitrile-styrene-acrylate copolymer (ASA) particles with different microstructure were synthesized by emulsion polymerization and then used for toughening poly(styrene-co-acrylonitrile) (SAN) resin. The structure of ASA particles was confirmed by FTIR. TEM results demonstrated that the particles with different morphologies of multilobe shape, complete core-shell and dumbbell shape were obtained depending on the cross-linker amount. It was found that the toughening efficiency reached the highest when the ASA particles had complete core-shell structure and the shell composition was close to that of the SAN matrix. It was ascribed to the fact that the complete shell layer and similar shell composition provided sufficient interfacial adhesion and transferred stress to induce larger matrix deformation, so that the notched impact strength increased accordingly. Moreover, the notched impact strength of SAN/ASA blend was improved without significantly sacrificing tensile strength when adding 30 wt% ASA particles with the size of around 400 nm. SEM results of the impact-fractured surfaces revealed that irregular fluctuation and numerous microvoids occurred. It was deduced that the toughening mechanism was attributed to the crazings and cavitation of particles. Therefore, this study paved a way of toughening the resin by adjusting the microstructure of the particles including morphology, composition, and size.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Jiahui Zhang,Xiao Wang,Lingcao Tan,Qiongyao Wang,Huiwen Yu,Wenhua Xu,Baiping Xu,Shuping Xiao,Jiarong Huang
The rising demand for polymers in engineering fields requires additional techniques to improve the toughness of inherently brittle plastics. Here, a strategy is proposed to toughen the brittle styrene–acrylonitrile copolymer (SAN) through dynamic vulcanization. Acrylonitrile-butadiene rubber (NBR) is introduced as a toughening agent, while dicumyl peroxide (DCP) is used as a curing agent to initiate dynamic vulcanization. The resulting SAN/NBR TPVs exhibit a co-continuous structure, different from the traditional “sea-island” structure of classical TPVs. The continuous NBR network functions as a pathway for stress transfer, playing a key role in toughening SAN. Significant plastic deformation and stretched microfibrils with high orientation form along the impact direction, absorbing energy and enhancing toughness. With 40 phr NBR, the SAN/NBR TPVs achieve an impact strength of 53.5 kJ/m 2 and a tensile toughness of 18.4 MJ/m 3 , which are 29.7 and 12.2 times higher than those of the neat SAN, respectively. Meanwhile, the tensile strength of the TPVs remains nearly the same as that of the simple blend.
研究领域:
高分子材料
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聚合物科学
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复合材料
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材料工程
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高分子加工
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力学性能
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功能材料
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DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Hong Huang,Xiang-Guang Meng,Wen-Wang Yu,Li-Yu Chen,Yan-Yan Wu
The isomerization of glucose to fructose provides an important way to expand the utilization of biomass. Herein, an amidoximated polyacrylonitrile (PAO) with an amidoxime functional group was prepared and used as an active heterogeneous catalyst for the isomerization of glucose to fructose. The PAO was characterized by SEM, XPS, and FTIR. The yield of fructose reached 48.9% with a selectivity of 98.6% for a 5 h reaction in aqueous solution at an initial pH of 6.5 and 85 °C. The pH caused a great influence on the conversion of glucose and selectivity of fructose while a little effect on the yield of fructose in the range of pH 5–10. The activation energy of isomerization reaction was evaluated as 79.7 kJ·mol–1. The catalysis mechanism was proposed, and the synergistic effect of oxime and amino groups played an important role in the isomerization of glucose. PAO maintained good catalytic activity after four cycles.
研究领域:
生物化学
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催化化学
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DOI
PubMed
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Yunjin Zhong,Haixiang Chen,Xiufang Chen,Bingying Zhang,Wenxing Chen,Wangyang Lu
As some of the most promising alternatives to traditional non-degradable materials, photodegradable materials have advantages of environmental benignity and rapid degradation under simple conditions. In this work, nontoxic TiO 2 and cost-effective g-C 3 N 4 have been compounded in a weight of 9:1 to form a photocatalytic additive with high activity. A 25 wt% loading of this photocatalytic additive has been incorporated into the polyacrylonitrile (PAN) by centrifugal electrospinning to prepare an abiotic degradable PAN material. Our results showed that the PAN chain could be almost fully degraded within 90 h in an aqueous medium under simulated sunlight in the absence of microorganisms . Product analysis implied that degradation of the PAN chain mainly involved the breaking of –CN and C–C bonds by radicals, followed by oxidation of terminal groups to carboxyl and gradual mineralization to CO 2 and H 2 O. This design strategy may provide new insight for the production and degradation mechanism of photodegradable polymer.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Wenji Zheng,Yuehu Guo,Ziheng Li,Xuehua Ruan,Xiaobin Jiang,Tiantian Li,Xiangcun Li,Yan Dai,Gaohong He
Polymer-supported MOFs membranes with high separation performances show great potentials in industrial purification of H 2 . The key to growing defect-free and adherent MOFs layers on polymer substrates is the abundant and uniformly distributed nucleation sites on the surface of polymer substrates. Therefore, in this work, a mixed-matrix polyacrylonitrile (PAN) substrate with ZIF-8-rich seed layer (ZS-PAN) was constructed by gravity induced deposition and gradient distribution of ZIF-8 before phase inversion, then under the assistance of Tannic acid (TA), the dense and defect-free ZIF-8 membrane on flexible polymer substrate was fabricated followed by the secondary growth of ZIF-8. The EDS and SEM results of the membrane cross-section confirm the gradient distribution of ZIF-8 seeds, and the resultant membranes are defect-free. The H 2 permeance of TA-ZIF-8/ZS-PAN membrane is 953.66 GPU, and the H 2 /CO 2 selectivity is 12.09, which is 80.17 % higher than that of ZIF-8/ZS-PAN membrane without TA, exceeding the Robeson upper bound in 2008. This improved H 2 separation performance is derived from the following reasons. First, gravity-induced ZIF-8 seed deposition constructs a ZIF-8-rich seed layer on the mixed-matrix polymer substrate, which increases the nucleation sites. Second, the introduction of TA during the secondary growth process further increases the nucleation sites by hydroxyl-chelated zinc ions, both of which contribute to the dense ZIF-8 membrane. At the same time, the hydroxyl group in TA is CO 2 -philic, which can delay CO 2 permeation and improve the H 2 /CO 2 separation performance by physically adsorbing CO 2 . The proposed mixed-matrix substrate by gravity induced deposition of MOFs provides a novel strategy for constructing defect-free and flexible MOFs membrane.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 12
·3434
·
IF 5.076
Haodong Zhao,Yali He,Zhihua Wang,Yanbao Zhao,Lei Sun
Emulsified oily wastewater threatens human health seriously, and traditional technologies are unable to separate emulsion containing small sized oil droplets. Currently, oil–water emulsions are usually separated by special wettability membranes, and researchers are devoted to developing membranes with excellent antifouling performance and high permeability. Herein, a novel, simple and low-cost method has been proposed for the separation of emulsion containing surfactants. Polyacrylonitrile (PAN) nanofibers were prepared via electrospinning and then coated by polydopamine (PDA) by using self-polymerization reactions in aqueous solutions. The morphology, structure and oil-in-water emulsion separation properties of the as-prepared PDA@PAN nanofibrous membrane were tested. The results show that PDA@PAN nanofibrous membrane has superhydrophilicity and almost no adhesion to crude oil in water, which exhibits excellent oil–water separation ability. The permeability and separation efficiency of n-hexane/water emulsion are up to 1570 Lm−2h−1bar−1and 96.1%, respectively. Furthermore, after 10 cycles of separation, the permeability and separation efficiency values do not decrease significantly, indicating its good recycling performance. This research develops a new method for preparing oil–water separation membrane, which can be used for efficient oil-in-water emulsion separation.Keywords:polyacrylonitrile;electrospinning;nanofibrous membrane;emulsion separation
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）