Biomass Conversion and Biorefinery
·
2013
·Vol. 4
·期 1
·59-66
·
IF 0
Li Hu,Zhang Qiuyun,Liu Jian,Liu Xiaofang,Chang Fei,Liu Yancai,Xue Wei,Yang Song
ZrMo mixed oxides modified by a series of low-cost monofunctional carboxylic acids including stearic acid, palmitic acid, myristic acid, and lauric acid were prepared and were characterized using TG analysis, XRD, FT-IR, NH 3 -TPD, and SEM techniques. These strong solid acids were evaluated as heterogeneous catalysts with porous property for the conversion of carbohydrates to 5-hydroxymethylfurfural (HMF) by oil heating rather than using microwave heating, in the aim of facilitating the industrial feasibility of this catalytic process and discussing the relation between surface acidity and reactivity in carbohydrates to HMF conversion. Under the optimal reaction conditions, moderate yields of HMF could be achieved from fructose, glucose, sucrose, and cellulose, and the strong solid catalysts can be recycled for seven times with no significant loss of activity.
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GREEN CHEMISTRY
·
2013
·Vol. 15
·期 10
·2895-2903
·
IF 6.828
Ruliang Liu,Jinzhu Chen,Xing Huang,Limin Chen,Longlong Ma,Xinjun Li
A series of sulfonic acid-functionalized carbon materials (C–SO3H), including poly(p-styrenesulfonic acid)-grafted carbon nanotubes (CNT-PSSA), poly(p-styrenesulfonic acid)-grafted carbon nanofibers (CNF-PSSA), benzenesulfonic acid-grafted CMK-5 (CMK-5-BSA), and benzenesulfonic acid-grafted carbon nanotubes (CNT-BSA), have been studied for fructose dehydration to 5-hydroxymethylfurfural (HMF) and fructose alcoholysis to alkyl levulinate. A study for optimizing the reaction conditions such as the catalyst loading, the reaction time, and the temperature has been performed. Under the optimal conditions, high HMF and ethyl levulinate yields of up to 89% and 86%, respectively, are obtained. The catalytic activities of C–SO3H for the conversions of fructose into both HMF and ethyl levulinate follow the order of their acid strength. The relationship between the catalytic activity and acid density of C–SO3H shows a linear correspondence in the fructose dehydration to HMF. The facile separation, ease of recovery, and high thermal stability make the developed C–SO3H efficient and environment-friendly catalytic materials for transforming biomass carbohydrate into fine chemicals.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2013
·
IF 3.458
Yanzhuo Zhang,Zhizhuang Zhi,Xue Li,Jian Gao,Yaling Song
The main objective of this study was to develop carboxylated ordered mesoporous carbon microparticles (c-MCMs) loaded with a poorly water-soluble drug, intended to be orally administered, able to enhance the drug loading capacity and improve the oral bioavailability. A model drug, carvedilol (CAR), was loaded onto c-MCMs via a procedure involving a combination of adsorption equilibrium and solvent evaporation. The physicochemical properties of the drug-loaded composites were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and HPLC. It was found that c-MCM has a high drug loading level up to 41.6%, and higher than that of the mesoporous silica template. Incorporation of CAR in both drug carriers enhanced the solubility and dissolution rate of the drug, compared to the pure crystalline drug. After loading CAR into c-MCMs, its oral bioavailability was compared with the marketed product in dogs. The results showed that the bioavailability of CAR was improved 179.3% compared with that of the commercial product when c-MCM was used as the drug carrier. We believe that the present study will help in the design of oral drug delivery systems for enhanced oral bioavailability of poorly water-soluble drugs.
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METABOLIC ENGINEERING
·
2013
·
IF 6.859
Wei Du,Feiyan Liang,Yangkai Duan,Xiaoming Tan,Xuefeng Lu
Because cyanobacteria are photosynthetic, fast-growing microorganisms that can accumulate sucrose under salt stress, they have a potential application as a sugar source for the biomass-derived production of renewable fuels and chemicals. In the present study, the production of sucrose by the cyanobacteria Synechocystis sp. PCC6803, Synechococcus elongatus PCC7942, and Anabaena sp. PCC7120 was examined. The three species displayed different growth curves and intracellular sucrose accumulation rates in response to NaCl. Synechocystis sp. PCC6803 was used to examine the impact of modifying the metabolic pathway on the levels of sucrose production. The co-overexpression of sps ( slr0045 ) , spp ( slr0953 ), and ugp ( slr0207 ) lead to a 2-fold increase in intracellular sucrose accumulation, whereas knockout of ggpS ( sll1566 ) resulted in a 1.5-fold increase in the production of this sugar. When combined, these genetic modifications resulted in a fourfold increase in intracellular sucrose accumulation. To explore methods for optimizing the transport of the intracellular sucrose to the growth medium, the acid-wash technique and the CscB (sucrose permease)-dependent export method were evaluated using Synechocystis sp. PCC6803. Whereas the acid-wash technique proved to be effective, the CscB-dependent export method was not effective. Taken together, these results suggest that using genetic engineering, photosynthetic cyanobacteria can be optimized for efficient sucrose production.
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INTERNATIONAL DAIRY JOURNAL
·
2013
·
IF 2.333
C.F. Guo,J.Y. Li
Elevated serum cholesterol is a major risk factor for coronary artery disease. Probiotics may manage elevated cholesterol. The hypocholesterolaemic effects of Lactobacillus casei F0822 and its functional mechanisms were investigated in rats . The serum total cholesterol, low-density lipoprotein cholesterol and liver total cholesterol levels significantly decreased in rats fed a high-cholesterol diet plus drinking water supplemented with viable cells of strain F0822; however, there was no significant difference in the serum high-density lipoprotein cholesterol levels among the treatment groups. The hypocholesterolaemic mechanisms of strain F0822 were attributed to its ability to suppress the reabsorption of bile acids into the enterohepatic circulation though hydrolysis of conjugated bile acids in the small intestine, binding of deoxycholic acid and hyodeoxycholic acid in the large intestine, and increase in propionate:acetate ratio in the large intestine in rats. Strain F0822 may be a promising probiotic culture with potential hypocholesterolaemic action in human.
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Food Analytical Methods
·
2015
·Vol. 8
·期 10
·2588-2594
·
IF 1.956
Jiang Ting-Fu,Chong Lei,Yue Mei-E,Wang Yuan-Hong,Lv Zhi-Hua
In this study, the separation and determination of carbohydrates in food samples were developed by capillary electrophoresis using dynamically coating the capillary with indirect UV detection. The polycationic polymers of hexadimethrine bromide (HDB) were used as electroosmotic flow (EOF) modifier to reverse the EOF. A highly alkaline pH condition was used in order to charge every carbohydrate negatively. Several important parameters influencing buffer concentration, pH, and HDB concentration were optimized. The optimal background electrolyte composed of 20 mmol L −1 sorbic acid, 0.005 % ( w / v ) HDB, and 40 mmol L −1 NaOH at pH 12.2. Under optimal conditions, 32 carbohydrates including mono-, di-, oligosaccharides, and sugar alcohols were separated in less than 12 min. The proposed method provided a good linearity, low limits of detection, and good repeatability of the carbohydrates. This method was then utilized to analyze carbohydrates in food samples. The results indicated that the developed method is an excellent alternative for the carbohydrate routine analysis in the food field.
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Journal of Energy Chemistry
·
2016
·
IF 2.322
Xiaofang Liu,Hu Li,Hu Pan,Heng Zhang,Shan Huang,Kaili Yang,Wei Xue,Song Yang
In this work, a series of MIL-101-SO 3 H( x ) polymeric materials were prepared and further used for the first time as efficient heterogeneous catalysts for the conversion of fructose-based carbohydrates into 5-ethoxymethylfurfural (EMF) in a renewable mixed solvent system consisting of ethanol and tetrahydrofuran (THF). The influence of –SO 3 H content on the acidity as well as on the catalytic activity of the porous coordination polymers in EMF production was also studied. High EMF yields of 67.7% and 54.2% could be successively obtained from fructose and inulin in the presence of MIL-101-SO 3 H (100) at 130 °C for 15 h. The catalyst could be reused for five times without significant loss of its activity and the recovery process was facile and simple. This work provides a new platform by application of porous coordination polymers (PCPs) for the production of the potential liquid fuel molecule EMF from biomass in a sustainable solvent system.
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Frontiers in Microbiology
·
2016
·
IF 4.165
Yang Jie,Wang Guozeng,Ng Tzi Bun,Lin Juan,Ye Xiuyun
Laccases can oxidize a wide range of aromatic compounds and are industrially valuable. Laccases often exist in gene families and may differ from each other in expression and function. Quantitative real-time polymerase chain reaction (qPCR) was used for transcription profiling of eight laccase genes in Cerrena sp. strain HYB07 with validated reference genes. A high laccase activity of 280.0 U/mL was obtained after submerged fermentation for 5 days. Laccase production and laccase gene transcription at different fermentation stages and in response to various environmental cues were revealed. HYB07 laccase activity correlated with transcription levels of its predominantly expressed laccase gene, Lac7. Cu2+ ions were indispensable for efficient laccase production by HYB07, mainly through Lac7 transcription induction, and no aromatic compounds were needed. HYB07 laccase synthesis and biomass accumulation were highest with non-limiting carbon and nitrogen. Glycerol and inorganic nitrogen sources adversely impacted Lac7 transcription, laccase yields, and fungal growth. The present study would further our understanding of transcription regulation of laccase genes, which may in turn facilitate laccase production as well as elucidation of their physiological roles.
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SOLAR ENERGY
·
2016
·
IF 3.685
Xiaodong Ren,Wenping Dang,Qiang Ma,Xuejie Zhu,Wei Zi,Lujian Jia,Bin Liu,Xisheng Zhang,Fengwei Xiao,Heqing Yang,Zhou Yang,Shengzhong (Frank) Liu
Superior texture-controlled ZnO thin film is prepared using a low cost electrochemical deposition process at open atmospheric condition. FE-SEM shows that the surface morphology can be altered from nanorods to microplates by adding a chemical additive. XRD analysis confirms that the crystalline growth direction and texture can be controlled by changing the additive concentration during the deposition. Using the optimized ZnO based back reflector (BR) in single junction a-SiGe:H solar cell device, we have achieved external quantum efficiency (EQE) as high as 87% at ∼550 nm; the EQE corrected short circuit current density ( J SC ) was 20.63 mA cm −2 and solar cell efficiency was 7.73% for the single junction a-SiGe:H solar cell. It proves to us that the high quality ZnO thin films can be produced at much reduced cost using electrochemical deposition for solar cell and other optoelectronic applications.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2017
·
IF 3.154
Shuangjie Wang,Ying Liu,Shasha Jiao,Ying Zhao,Yirong Guo,Mengcen Wang,Guonian Zhu
Neonicotinoid insecticides are commonly used for pest control on tea plantations as a result of their broad-spectrum activity. However, neonicotinoid residues released from tea leaves into tea infusions pose a dietary risk to consumers. Therefore, a rapid, sensitive, and reliable on-site detection method for neonicotinoids is needed. We developed a quantum-dot-based fluorescent lateral flow immunochromatographic strip (LFICS) combined with a broad-specific antibody for detection of typical neonicotinoids (imidacloprid, imidaclothiz, and clothianidin), with sensitivities [50% inhibitory concentration (IC50)] of 0.104–0.33 ng/mL and visual detection limits of 0.5–1 ng/mL. The strip assay could be completed in less than 30 min. Using the LFICS to analyze spiked tea samples (green tea, black tea, and oolong tea), the average recovery of the three neonicotinoids ranged between 71 and 111%, with the coefficient of variation below 12%. The results from the LFICS tests for field samples were consistent with results from ultraperformance liquid chromatography–tandem mass spectrometry. The newly developed strip is a useful tool for the on-site detection of neonicotinoid residues in tea.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2017
·Vol. 218
·期 19
·1700141
·
IF 2.5
Qiankun Zhu,Xiaoming Li,Yonghua Xiao,Yan Xiong,Suiping Wang,Changli Xu,Jun Zhang,Xuewen Wu
The mild environment where most proteins and antibodies in living systems are prepared has inspired fascination among chemists. Herein, a new, rapid, low-cost, and environment-friendly method is proposed to synthesize molecularly imprinted polymers (MIPs) via visible light activated reversible addition–fragmentation chain transfer polymerization in aqueous media at room temperature for highly selective electrochemical assay of glucose. The MIPs with microsphere morphology, the better hydraulic distribution, large surface area, uniform large pore sizes, and high pore volume exhibit a significant adsorption efficiency compared with nonimprinted polymers for glucose. In addition, the MIP sensor recognizing the glucose significantly exceeds that of the other saccharide analogs, possesses regenerative ability, and presents high sensitivity by applying for the detection of glucose in human urine samples.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2017
·
IF 3.255
Tong Wang,Jiao Jiao,Qing-Yan Gai,Peng Wang,Na Guo,Li-Li Niu,Yu-Jie Fu
Nowadays, green extraction of bioactive compounds from medicinal plants has gained increasing attention. As green solvent, deep eutectic solvent (DES) have been highly rated to replace toxic organic solvents in extraction process. In present study, to simultaneous extraction five main bioactive compounds from fig leaves, DES was tailor-made. The tailor-made DES composed of a 3:3:3 molar ratio of glycerol, xylitol and D-(−)-Fructose showed enhanced extraction yields for five target compounds simultaneously compared with traditional methanol and non-tailor DESs. Then, the tailor-made DES based extraction methods have compared and microwave-assisted extraction was selected and optimized due to its high extraction yields with lower time consumption. The influencing parameters including extraction temperature, liquid-solid ratio, and extraction time were optimized using response surface methodology (RSM). Under optimal conditions the extraction yield of caffeoylmalic acid, psoralic acid-glucoside, rutin, psoralen and bergapten was 6.482 mg/g, 16.34 mg/g, 5.207 mg/g, 15.22 mg/g and 2.475 mg/g, respectively. Macroporous resin D101 has been used to recovery target compounds with recovery yields of 79.2%, 83.4%, 85.5%, 81.2% and 75.3% for caffeoylmalic acid, psoralic acid-glucoside, rutin, psoralen and bergapten, respectively. The present study suggests that DESs are truly designer and efficient solvents and the method we developed was efficient and sustainable for extraction main compounds from Fig leaves.mg/g
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