APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
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IF 11.698
Hua Zhou,Huanghui Xu,Yun Liu
Deriving more valuable products from renewable lignocellulosic biomass is attractive but still remains major challenges, the insufficient lignin valorization is considered as one of the main obstacles. Here, we report a novel catalyst comprised of cobalt nanoparticles (NPs) encapsulated in graphitic carbon tailored with manganese and nitrogen heteroatoms (Co-Mn/N@C), fabricated by pyrolyzing a mixture of Co/Mn-lignin complex and dicyandiamide. The as-synthesized Co-Mn/N@C catalyst exhibits excellent activity and recyclability for oxidizing biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) in aqueous system using O 2 as oxidant. The structure-performance relations of the catalyst are investigated, suggesting that Mn/N-doped carbon can activate the reactivity of Co NPs for HMF oxidation by tuning the electronic structure of embedded metal NPs. Additionally, isotopic labelling experiments reveal the role of water and O 2 for FDCA production using Co-Mn/N@C as catalyst. This work not only demonstrates the integrated biorefinery strategy, but also provides a new approach for sustainable, low-cost heterogenous catalysts preparation.
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JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
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2018
·Vol. 99
·期 6
·3192-3202
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IF 2.379
Zhisheng Zhou,Xing Hu,Guowen Zhang,Rui Wang,Deming Gong
BACKGROUND 5-Hydroxymethyl-2-furaldehyde (5-HMF), a by-product of the Maillard reaction, usually present in fried and baked food, may cause potential harm to the human body. Here, the interaction between 5-HMF and calf thymus DNA (ctDNA) under physiological buffer (pH 7.4) was studied using multi-spectroscopic methods combined with multivariate curve resolution–alternating least squares (MCR-ALS) chemometrics and molecular simulation techniques. RESULTS The concentration profiles and pure spectra of the three components (5-HMF, ctDNA and 5-HMF–ctDNA complex) were extracted from highly overlapping spectra using MCR-ALS analysis, which verified the formation of 5-HMF–ctDNA complex. The binding constant being of the order of 10 3 L mol −1 at four temperatures (292, 298, 304 and 310 K) indicated a weak affinity in the binding of 5-HMF to ctDNA. The binding interaction was mainly driven by hydrogen bonds and van der Waals forces. Viscosity analysis, melting assay, ionic strength effect and competitive fluorescence studies ascertained that 5-HMF bound to ctDNA through groove binding, and it tended to bind to guanine–cytosine rich region of ctDNA which was characterized using Fourier transform infrared spectra and molecular docking. Circular dichroism spectral analysis and DNA cleavage assays indicated that the ctDNA conformation was altered from B to A form and 5-HMF caused DNA damage at higher concentration. CONCLUSIONS The results suggested that 5-HMF bound to ctDNA through groove binding and caused DNA damage. This research may contribute to understand the binding mechanism of 5-HMF to ctDNA and to the assessment of the toxicological effect of 5-HMF in biological processes. © 2018 Society of Chemical Industry
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RSC Advances
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2019
·Vol. 9
·期 16
·9041-9048
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IF 3.049
Xiaofeng Li,Yi Wang,Xiaomin Xie,Changhong Huang,Sen Yang
This work prepared carbonaceous microspheres by hydrothermal carbonization of yeast cells followed by sulfonation with concentrated sulphuric acid (98%) at room temperature. The obtained carbonaceous product (CM-SO3H) had a high acid density (1.80 mmol g−1). We evaluated CM-SO3H as a solid catalyst for the dehydration of fructose-based carbohydrates to 5-hydroxymethylfurfural (5-HMF) in the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]). The effects of the catalyst and substrate loadings as well as the reaction temperature and time on the yield of 5-HMF were investigated. Under the optimum conditions, a 5-HMF yield of up to 83.5% was obtained from fructose with a reaction temperature of 80 °C for 30 min. Furthermore, 44.8% and 59.2% 5-HMF yields were obtained from sucrose (80 °C for 30 min) and inulin (80 °C for 60 min), respectively. CM-SO3H and [BMIM][Cl] showed high stability and could be recycled between five and eight times without significant loss of catalytic activity. More importantly, the catalytic system could be applied to high substrate concentrations. CM-SO3H combined with [BMIM][Cl] is a promising system for transforming fructose-based carbohydrates into 5-HMF.
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APPLIED SURFACE SCIENCE
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2019
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IF 5.155
Wei Zhuang,Weiwei Gu,Qianqian Zhu,Jiahua Zhu,Zhenfu Wang,Huanqing Niu,Dong Liu,Jinglan Wu,Yong Chen,Ming Li,Chenjie Zhu,Hanjie Ying
In order to solve the toxic and hazardous issues of the agents in the chemical reduction process of graphene oxide (GO), disodium guanosine 5′-monophosphate (GMP-2Na) was used as an ideal reducing agent for the synthesis of functionalized GO (FGO) for lipase immobilization. At the condition of low amount adsorption of GMP-2Na indicated by the N1s spectra of X-ray photoelectron spectroscopy (XPS), the C/O atomic ratio of the FGO increased from 2.09 to 3.12, indicating the reduction of GO. As the amount of GMP-2Na increased, the intensity of the characteristic peak of GO in the XRD pattern decreased, and the I D /I G peak intensity of Raman spectra increased during the functionalization process. It was found that when the concentration of GMP-2Na is 0.20 mg/mL, the degree of hydrophobicity of FGO is conducive to the formation of optimal conformation of lipase. After immobilization, the activity of the immobilized enzyme reaches twice the value of free enzyme. At the same time, the protein loading reaches to 600 mg/g. The immobilized enzyme showed enhanced durability since no obvious decrease was observed after incubation for 8 h at pH 6.0 and pH 7.0. After storage for 35 days, the activity of GO-G@ enzyme was 54.47% higher than that of free enzyme. GO reduced by GMP-2Na provides a possibility to obtain a highly efficient lipase immobilization carrier.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2019
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IF 2.931
Yanqing Wang,Qianqian Han,Hongmei Zhang
Among the side effects of 5-fluorouracil (5-FU), the performance of the gastrointestinal reactions is faster and more obvious than others. In this work, the effects of 5-FU on the activities and conformational structures of the important digestive enzymes including α-amylase, pepsin and trypsin were studied to analyze the mechanism of the gastrointestinal adverse effects causing by 5-FU binding. The results showed that the enzymatic activity of pepsin was obviously reduced by the presence of 5-FU that bound directly to the enzyme activity cavity site. The molecular modeling and fluorescence quenching data indicated that the hydrophobic, polar and hydrogen bonding forces were involved in the ground state complex formation between proteases and 5-FU. In addition, 5-FU changed the tertiary structures of α-amylase, pepsin, and trypsin.
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APPLIED CATALYSIS A-GENERAL
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2019
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IF 4.63
Tingting Zhao,Fuwei Li,Hongchang Yu,Shilei Ding,Zhixia Li,Xinyuan Huang,Xiang Li,Xiaohan Wei,Zhenlin Wang,Hongfei Lin
Conversion of biomass-derived chemicals into light olefins is a promising method to maintain sustainable development of light olefin industry. In this study, three mesoporous ZSM-5 zeolites (MZSM-5-A, MZSM-5-B and MZSM-5-C) with major pore diameter about 4.8 nm, 16 nm and 22 nm were synthesized using a hydrothermal method by utilizing different templates. The catalytic activity of catalysts was studied by catalytic cracking of ethanol and oleic acid. The influence of reaction temperature on conversion and product selectivity was investigated. The characterization of ZSM-5 samples showed that the orders of the external surface area and mesopore volume were MZSM-5-C > MZSM-5-B > MZSM-5-A > conventional HZSM-5. In ethanol to light olefin reaction, MZSM-5-C achieved the highest light olefin yield (318.3 mL g −1 ) and ethylene selectivity (42.3%) at 400 °C. In oleic acid to light olefin reaction, MZSM-5-B achieved a complete conversion of oleic acid at 500 °C, and obtained the highest light olefin selectivity (38.1%) at 550 °C. The difference may be relevant to the size and chemical structure of feedstock molecular as well as the acidity of catalysts. Regardless of ethanol or oleic acid as feedstock, introduction of mesopore in zeolites significantly enhanced the light olefin yield and selectivity.
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BIORESOURCE TECHNOLOGY
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2018
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IF 5.807
Leilei Dai,Yunpu Wang,Yuhuan Liu,Roger Ruan,Dengle Duan,Yunfeng Zhao,Zhenting Yu,Lin Jiang
Catalytic fast pyrolysis (CFP) of torrefied corn cob using Ni-modified hierarchical ZSM-5 catalyst was conducted in this study. The prepared catalysts were characterized by N 2 adsorption and desorption (N 2 -BET), X-ray diffraction (XRD), and temperature-programmed desorption of NH 3 (NH 3 -TPD). NaOH solution treatment resulted in the lower peak intensities of hierarchical ZSM-5 catalyst in the XRD patterns while Ni modification improved the catalyst framework. In addition, NaOH solution treatment created some mesopores or macropores, but the incorporation of Ni reduced BET surface area and volume of micropores. Though the addition of Ni lowered the acidity of catalyst, Ni-modified hierarchical ZSM-5 catalyst led to higher yields and of aromatic hydrocarbons. What is more, hierarchical ZSM-5 catalysts significantly improved the selectivities of mono-aromatics. Kinetic analysis shows that CFP of torrefied corn cob was second-order reaction and the addition of Ni can obtain a lower activation energy compared with hierarchical ZSM-5 catalyst.
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APPLIED CATALYSIS A-GENERAL
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2018
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IF 4.521
Zhi Cao,Ming Li,Yong Chen,Tao Shen,Chenglun Tang,Chenjie Zhu,Hanjie Ying
The widely available reagent ethylenediaminetetraacetic acid (EDTA) was used as a temperature-responsive catalyst to produce 5-hydroxymethylfurfural (HMF) from fructose. Using this catalyst, a remarkable HMF yield of 89 ± 3% was achieved in a water-MIBK biphasic system containing polyvinylpyrrolidone (PVP) and 2-butanol. The pH of the reaction system based on EDTA as a catalyst was shown to be temperature-responsive. Moreover, the EDTA catalyst could be recycled simply by cooling the reaction liquid to room temperature due to its temperature-dependent solubility in water. A slight decrease in the yield of HMF (from 89 ± 3 to 81 ± 2%) was observed after EDTA repeated use for five cycles, and a yield of 88 ± 2% was achieved again after purification of the recycled EDTA via recrystallization with NaOH/HCl. The FTIR spectrum of recycled EDTA was almost the same as that of fresh catalyst, and TG analysis showed the decomposition temperature of EDTA is about 260 °C. Furthermore, a leaching test revealed that only 4.3 ± 0.2% of the initial EDTA was lost after five-time reuse.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Zhen Zhang,Jiang Wu,Bin Li,Huibin Xu,Dongjing Liu
Zeolite (ZSM-5), as a kind of carbon-free sorbent or catalyst, has been widely applied in many fields due to its big surface area, good chemical and thermal stability, and excellent adsorption performance. In this study, Mn-Fe modified ZSM-5 are synthesized via sol-gel approach and employed for elemental mercury (Hg 0 ) removal from simulated flue gas at low temperature. The results show that pure ZSM-5 shows poor mercury capture ability with Hg 0 removal efficiency of ~8.5–18.8% at 100–300 °C. Mn or Fe modification can both efficiently enhance the Hg 0 removal efficiency of the ZSM-5. The sorbent with Mn/Fe molar ratio of 1:2 exhibits the optimal mercury capture ability with the highest Hg 0 removal efficiency near 100% at temperatures of 200 and 250 °C due to the significant synergy effect between Mn 2 O 3 and Fe 2 O 3 . The presence of NO has a negligible effect on the Hg 0 removal performance of Mn/ZSM-5 and Mn1Fe2/ZSM-5, while the existence of SO 2 considerably degrades the Hg 0 capture performance of Mn/ZSM-5 owing to competing adsorption and side reactions. Fe addition can protect Mn active sites from SO 2 poisoning and thereby enhancing the SO 2 resistance of Mn/ZSM-5 to some extent.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Qian Yao,Ying Zhang,Yao Fu
We report on catalytic fast pyrolysis microalgae under ammonia atmosphere into acetonitrile over Ga/HZSM-5, which provides a long-term sustainable option for acetonitrile production and microalgae valorization. The effect of various catalysts, reaction conditions and species of microalgae on acetonitrile production was explored systematically. Under the optimized conditions, the maximum carbon yield of acetonitrile from Chlorella vulgaris was 23.4%, and the selectivity of acetonitrile in bio-oil was up to 77.2%. The possible reaction pathways were proposed according to the comprehensive experimental investigation on the conversion of model compounds and intermediates (proteins, carbohydrates, lipids, amino acids, carboxylic acids, furans, and amines). High-resolution transmission electron microscopy (TEM) analysis showed that Ga was present mainly at the outer surface of zeolite crystals, and a small amount of Ga was doped into the zeolite crystals.
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ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
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2018
·Vol. 62
·期 2
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IF 4.256
Cheng Wang,Gaomei Zhao,Song Wang,Yin Chen,Yali Gong,Shilei Chen,Yang Xu,Mengjia Hu,Xinmiao Wang,Hao Zeng,Aiping Wang,Dengqun Liu,Yongping Su,Tianmin Cheng,Fang Chen,Junping Wang
The increasing incidence of multidrug-resistant Acinetobacter baumannii (MDRAb) infections worldwide has necessitated the development of novel antibiotics. Human defensin 5 (HD5) is an endogenous peptide with a complex architecture and antibacterial activity against MDRAb. In the present study, we attempted to simplify the structure of HD5 by removing disulfide bonds. We found that the Cys2-4 bond was most indispensable for HD5 to inactivate MDRAb, although the antibacterial activity of the derivative was significantly attenuated. We then replaced the noncationic and nonhydrophobic residues with electropositive Arg to increase the antibacterial activity of HD5 derivative that contains a Cys2-4 bond, obtaining another derivative termed HD5d5. The in vitro antibacterial assay and irradiation-wound-infection animal experiment both showed that HD5d5 was much more effective than HD5 at eliminating MDRAb. Further investigations revealed that HD5d5 efficiently bound to outer membrane lipid A and penetrated membranes, leading to bacterial collapse and peptide translocation. Compared to HD5, more HD5d5 molecules were located in the cytoplasm of MDRAb, and HD5d5 was more efficient at reducing the activities of superoxide dismutase and catalase, causing the accumulation of reactive oxygen species that are detrimental to microbes. In addition, HD5 failed to suppress the pathogenic outer membrane protein A of Acinetobacter baumannii (AbOmpA) at concentrations up to 50 μg/ml, whereas HD5d5 strongly bound to AbOmpA and exhibited a dramatic toxin-neutralizing ability, thus expanding the repertoire of drugs that is available to treat MDRAb infections.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2018
·
IF 3.997
Hai-Bo Wang,Li-Hong Ma,Bi-Yun Fang,Yuan-Di Zhao,Xue-Bin Hu
This study has reported that a GR-5 DNAzyme based lead ion strip biosensor could exhibit an enhanced specificity with the assistance of graphene oxide (GO). This enhancement results from the specific π-stacking interaction between the ribose rings of the nucleobases and the carbon hexagons in GO which can reduce the false positive interference by removing unhybridized ssDNA during the annealing of GR-5 DNAzyme. Meanwhile, conjugate pad was sprayed with two kinds of AuNP-DNA probes, and nitrocellulose membrane test zone and control zone were immobilized with two kinds of biotin-DNA probes, respectively. The limit of detection of this strip biosensor was estimated to be about 0.05 nM (S/N = 3) and 1 nM (with naked eyes) with a linear range from 0.01 to 100 μM. Furthermore, the strip biosensor exhibited excellent selectivity toward Pb 2+ in the presence of other divalent metal ions. For real soil samples, the obtained recoveries were in the range from 91.5% to 113.1%.
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