FUEL
·
2018
·
IF 4.908
Tao Chen,Lincai Peng,Xin Yu,Liang He
A series of carbonaceous solid acid catalysts were prepared by facile carbonization and sulfonation of biorenewable feedstocks (i.e., glucose, sucrose, starch and cellulose), and employed for directly converting carbohydrates in ethanol medium to synthesize 5-ethoxymethylfurfural (EMF). The carbonization temperature of cellulose and starch (500 °C) was required to be higher than that of glucose and sucrose (400 °C) to realize high –SO 3 H density and EMF yield. Based on rich exploitability of cellulose and good activity of its derived carbonaceous catalyst, magnetic cellulose-derived carbonaceous solid acid (MCC-SO 3 H) was subsequently synthesized, which possessed a porous structure with BET surface area of 35.34 m 2 g –1 , high –SO 3 H density (1.28 mmol g –1 ) and sufficient magnetism for separation (1.99 emu g –1 ). By optimizing the process variables, a maximum EMF yield of 63.2% could be achieved from fructose at 120 °C, and ethyl levulinate formation was favored at elevated temperature. The MCC-SO 3 H catalyst could be readily separated from the reaction mixture by an external magnet with recovery rate of 92.6% after six successive runs, and reused repeatedly with little deactivation. Besides, this catalyst was efficient for the one-pot transformation of fructose-based polysaccharides into EMF, affording yields of 51.3% and 32.5% from inulin and sucrose, respectively. With glucose as the substrate, instead ethyl glucoside with a high yield of 86.5% was obtained.
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高影响因子
MOLECULES
·
2018
·Vol. 23
·期 3
·554
·
IF 3.098
Qianqian Liang,Qiuying Wang,Yuan Wang,Ya-nan Wang,Jia Hao,Miaomiao Jiang
The primary metabolites in aqueous extract of mulberry (Morus albaL.) leaves were characterized by using proton nuclear magnetic resonance (1H-NMR) spectroscopy. With the convenience of resonance assignment, GABA together with the other 10 primary metabolites was simultaneously identified and quantified in one1H-NMR spectrum. In this study, external calibration curves for metabolites were employed to calculate the concentrations of interests. The proposed quantitative approach was demonstrated with good linearity (r2ranged in the interval of 0.9965–0.9999), precision, repeatability, stability (RSD values in the ranges of 0.35–4.89%, 0.77–7.13% and 0.28–2.33%, respectively) and accuracy (recovery rates from 89.2% to 118.5%). The established1H-NMR method was then successfully applied to quantify 11 primary metabolites in mulberry leaves from different geographical regions within a rapid analysis time and a simple sample preparation procedure.Keywords:quantitative1H-NMR;Morus alba;amino acids;saccharides;organic acids
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PubMed
高影响因子
CATALYSIS COMMUNICATIONS
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2018
·
IF 3.463
Xilei Lu,Lixin Wang,Xiuyang Lu
Metal organic frameworks (MOFs) are promising heterogeneous catalysts for biomass conversion to useful chemicals. In this work, four M-MOF-74s (Co, Ni, Mg, Zn) were synthesized at room temperature. Among these, Mg-MOF-74 exhibited the best catalytic activity for conversion of sugars to methyl lactate. A final product yield of methyl lactate from glucose of 35% was achieved with complete conversion of glucose at optimal reaction conditions. Catalytic performance of conversion of five sugars to methyl lactate over Mg-MOF-74 was studied, a product yield of 47% were obtained from sucrose. Mg-MOF-74 catalyst has shown to be reusable for at least three cycles.
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高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2018
·Vol. 19
·期 3
·683
·
IF 3.687
Quan Gan,Xin Li,Xinwei Zhang,Lanlan Wu,Chongjun Ye,Ying Wang,Junshan Gao,Yan Meng
β-fructofuranosidase (β-FFase) belongs to the glycosyl-hydrolase family 32 (GH32), which can catalyze both the release of β-fructose from β-d-fructofuranoside substrates to hydrolyze sucrose and the synthesis of short-chain fructooligosaccharide (FOS).BmSuc1has been cloned and identified from the silkwormBombyx morias a first animal type of β-FFase encoding gene. It was hypothesized that BmSUC1 plays an important role in the silkworm-mulberry adaptation system. However, there is little information about the enzymatic core sites of BmSUC1. In this study, we mutated three amino acid residues (D63, D181, and E234) that represent important conserved motifs for β-FFase activity in GH32 to alanine respectively by using site-directed mutagenesis. Recombinant proteins of three mutants and wild type BmSUC1 were obtained by using a Bac-to-Bac/BmNPV expression system and BmN cells. Enzymatic activity, kinetic properties, and substrate specificity of the four proteins were analyzed. High Performance Liquid Chromatography (HPLC) was used to compare the hydrolyzing and transfructosylating activities between D181A and wtBmSUC1. Our results revealed that the D63A and E234A mutations lost activity, suggesting that D63 and E234 are key amino acid residues for BmSUC1 to function as an enzyme. The D181A mutation significantly enhanced both hydrolyzing and transfructosylating activities of BmSUC1, indicating that D181 may not be directly involved in catalyzation. The results provide insight into the chemical catalyzation mechanism of BmSUC1 inB. mori. Up-regulated transfructosylating activity of BmSUC1 could provide new ideas for usingB. moriβ-FFase to produce functional FOS.Keywords:Bombyx mori;β-fructofuranosidase;site-directed mutagenesis;hydrolysis;transfructosylation
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PubMed
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 9
·5439-5453
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IF 1.674
Huang Feng,Li Wenzhi,Zhang Tingwei,Li Dawei,Liu Qiyu,Zhu Xifeng,Ma Longlong
A carbonaceous solid acid catalyst with high strong-acid density was synthesized by facile functionalization of a biomass-derived mesoporous carbon with benzenesulfonic acid. The catalyst was characterized by using Fourier transform infrared spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, and N 2 adsorption–desorption. The carbonaceous solid catalyst containing Brønsted acid sites was used for the production of 5-hydroxymethylfurfural (HMF) from hexoses such as fructose, glucose, and cellulose in γ-valerolactone (GVL)-H 2 O mixture. By reaction at 130 °C for 20 min using fructose as a feedstock, an HMF yield 78.1% was achieved. The catalytic performance of the catalyst in conversion of fructose into HMF hardly changed over seven cycles, demonstrating that the catalyst had excellent recyclability. The yields of HMF derived from glucose and cellulose reached 33.2 and 22.5%, respectively, whereas those of total furans were 42.1 and 33.7%, respectively. The proposed reaction system was promising in transforming biomass-based carbohydrates into fine chemicals, given the use of green functionalization methods, the utilization of sustainable biomass-derived carbon precursor and solvents, catalyst with high acid density, and the availability of high HMF yield.
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高影响因子
ACS Nano
·
2018
·
IF 13.709
Yaxin Chen,Liluo Shi,Qiong Yuan,Ang Li,Shaozhuan Huang,Hui Ying Yang,Xiaohong Chen,Jisheng Zhou,Huaihe Song
Although nucleation and crystallization in solution-processed materials synthesis is a natural phenomenon, the morphology design of graphene nanosheets by controlling the dual crystallization has not been established. In this work, we systematically demonstrate how the dual crystallization of ice and potassium chloride induces the morphological variation of the freeze-dried scaffold from fractal structure toward stepped sheet-like structure. A denim-like graphene nanosheet (DGNS) has been fabricated by annealing the F127-coated stepped sheet-like scaffold in nitrogen. DGNS shows parallel and straight stripes with an average stripe spacing of 10 nm. When used as a lithium-ion battery anode, DGNS possesses a superhigh reversible capacity of 1020 mAh g–1 at the current density of 1 A g–1 after 600 cycles. This work reports the control of dual crystallization of ice and salt crystals and provides an efficient way to design the morphology of two-dimensional materials by adjusting the crystallization.
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PubMed
高影响因子
ENERGY
·
2018
·
IF 4.968
Wenjing Yuan,Anjian Xie,Ping Chen,Fangzhi Huang,Shikuo Li,Yuhua Shen
Finding an effective approach to prepare low-cost metal-free catalysts with excellent catalytic performance for the oxygen reduction reaction (ORR) is a crucial challenge for the commercialization of fuel cells. Herein, a novel and effective combustion approach was designed in order to construct the three-dimensional porous carbon foam and followed by heat treatment in an NH 3 atmosphere. In the combustion process , sucrose was used as the carbon source to produce the carbon framework, sodium bicarbonate as the pore-foaming agent to form the porous structure . This synthetic route is novel, cost-effective and without using any templates, expensive equipment as well as highly toxic chemical reagents. Compared with the control samples, the typical product exhibits the excellent catalytic activity in terms of not only a positive onset potential and high current density , but also low H 2 O 2 yield and approximate four-electron reaction pathway in alkaline media . The reason may be attributed to the synergistic effect of the three-dimensional porous structure, high BET surface area (up to 1216 m 2 g −1 ) and effective nitrogen-doping of the product. In addition, the novel method is of great importance, which may guide future efforts for the development of other porous carbon-based materials for applications in multi-fields.
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Li-Feng Fang,Ming-Yong Zhou,Liang Cheng,Bao-Ku Zhu,Hideto Matsuyama,Shuaifei Zhao
A polyvinyl chloride (PVC)-based positively-charged nanofiltration membrane was fabricated from polyvinyl chloride- graft -poly( N,N -dimethylaminoethyl methacrylate) by heating and crosslinking treatment. We characterized the surface chemical compositions, membranes structures, surface hydrophilicity and surface charges of the prepared membrane. The estimated membrane pore diameter is 1.98 nm and the pore diameters are in the range of 0.5–2.0 nm. The membrane exhibits excellent water permeability (9.3 L m −2 h −1 bar −1 ) and salt rejection (93.1% with MgCl 2 solution). Both the heating treatment and crosslinking reaction can diminish the pore size of the precursor membrane. The membrane hydrophilicity is improved after quaternization, leading to higher water permeability compared with the membrane treated by heating only. Moreover, surface quaternization and crosslinking offer the membrane excellent pressure resistance and long-term stability. The prepared nanofiltration membrane has great promise in many applications including water softening and multivalent ion removal.
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高影响因子
RSC Advances
·
2018
·Vol. 8
·期 61
·34877-34882
·
IF 2.936
Xue Han,Zhixin Qin,Mengyao Zhao,Jiajia Song,Fei Qu,Fengli Qu,Rong-Mei Kong
The illegal adulteration of melamine in dairy products for false protein content increase is a strong hazard to human health. Herein, a simple and sensitive colorimetric method was developed for the quantification of melamine in dairy products based on a Cu2+-hydrogen peroxide (H2O2)-3,3′,5,5′-tetramethylbenzidine (TMB) system. In this strategy, Cu2+ exhibits peroxidase-like activity and can catalyze the oxidation of TMB to oxidized TMB (oxTMB) in the presence of H2O2 with a blue colour change of the solution. However, the presence of melamine quickly interacts with H2O2 leading to the consumption of H2O2 and thus strongly hinders the oxidation of TMB. Under the optimal conditions, the absorbance change of oxTMB has a linear response to the concentration of melamine from 1 to 100 μM with a detection limit of 0.5 μM for melamine. The proposed method has many merits including more simplicity, good selectivity, and more cost-effectiveness without using any nanomaterials. The method was further successfully applied to detect melamine in dairy products including milk and infant formula powder.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2018
·
IF 3.779
Fuping Li,Zhuoli Xu,Kang Zhao,Yufei Tang
ZrB 2 -ZrC composite nanofibers were fabricated by electrospinning and carbothermal reduction. The morphology, phase composition and interface were characterized. The fabricated ZrB 2 -ZrC composite nanofibers are uniform and the diameter is about 100 nm. The effects of heat-treatment temperature, n(B)/n(Zr) and n(C)/n(Zr) on the microstructure and phase composition of composite nanofibers were systematically investigated. The results shows heat-treatment temperature has influence on the phase composition and grain size of the ZrB 2 -ZrC composite nanofibers. The content of ZrC in the ZrB 2 -ZrC composite nanofibers can be adjusted by the value of n(B)/n(Zr) in the precursors. As n(B)/n(Zr) equal to 3.5, the mass ratio between ZrB 2 and ZrC is about 48:52 which is very close to the eutectic composition of ZrB 2 -ZrC composites. The value of n(C)/n(Zr) also affects the phase composition of composite nanofibers. Reaction process and phase evolution during heat-treatment were studied based on analysis of reaction thermodynamics. The value of n(B)/n(Zr) influences the phase evolution during fabrication of ZrB 2 -ZrC composite nanofibers. The tensile mechanical properties were tested, indicating that the addition of ZrC has the ability to improve the plasticity of ZrB 2 .
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高影响因子
Biochimica et Biophysica Acta-Gene Regulatory Mechanisms
·
2018
·
IF 5.179
Quan Gan,Xinwei Zhang,Daobo Zhang,Liang Shi,Yue Zhou,Tongtong Sun,Song Jiang,Junshan Gao,Yan Meng
Sucrose is the most commonly transported sugar in plants and is easily assimilated by insects to fulfill the requirement of physiological metabolism. BmSuc1 is a novel animal β-fructofuranosidase (β-FFase, EC 3.2.1.26) - encoding gene that was firstly cloned and identified in silkworm , Bombyx mori . BmSUC1 was presumed to play an important role in the silkworm-mulberry enzymatic adaptation system by effectively hydrolyzing sucrose absorbed from mulberry leaves. However, this has not been proved with direct evidence thus far. In this study, we investigated sucrose hydrolysis activity in the larval midgut of B. mori by inhibition tests and found that sucrase activity mainly stemmed from β-FFase, not α-glucosidase. Next, we performed shRNA-mediated transgenic RNAi to analyze the growth characteristics of silkworm larvae and variations in glycometabolism in vivo in transgenic silkworms. The results showed that in the RNAi- BmSuc1 transgenic line, larval development was delayed, and their body size was markedly reduced. Finally, the activity of several disaccharidases alone in the midgut and the sugar distribution, total sugar and glycogen in the midgut, hemolymph and fat body were then determined and compared. Our results demonstrated that silencing BmSuc1 significantly reduced glucose and apparently activated maltase and trehalase in the midgut. Together with a clear decrease in both glycogen and trehalose in the fat body, we conclude that BmSUC1 acts as an essential sucrase by directly modulating the degree of sucrose hydrolysis in the silkworm larval midgut, and insufficient sugar storage in the fat body may be responsible for larval malnutrition and abnormal petite phenotypes.
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高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Bo Zhang,Weichen Gao,Jiafang Piao,Yunjie Xiao,Bin Wang,Weipan Peng,Xiaoqun Gong,Zefang Wang,Haitao Yang,Jin Chang
Nowadays, increasing analytical sensitivity is still a big challenge in constructing membrane-based fluorescence immunochromatography test strips (FICTS). However, the bioactivity of antibody (Ab) immobilized on the test line (T line) of porous nitrocellulose membrane (PNM), which directly influences the analytical sensitivity, is less studied. In this work, a novel amphiphilic hydrophobin (HFBI) protein was introduced to modify the T line to effectively retain the Abs’ bioactivity. The results indicated that HFBI could self-assemble on the PNM and immobilize the Abs in the “stand-up” orientation. Compared with the conventional FICTS, the HFBI-modified FICTS with only 0.2 mg/mL of monoclonal Abs on T line enable more accurate quantitative detection and better sensitivity (0.06 ng/mL for prostate specific antigen), which is more than 2 orders of magnitude lower than that of the conventional FICTS with the same concentration of monoclonal Abs on T line. Furthermore, the accuracy of this HFBI-modified FICTS was investigated by testing 150 clinical serum samples and the detection results were coincident with those by electrochemiluminescence immunoassay. Our results provide a novel and promising strategy of Ab immobilization on FICTS for near-patient and point-of-care application.
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高影响因子
危险品化学品经营许可证（带存储）