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1.
Food Chem ; 141(4): 3578-85, 2013 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-23993524

RESUMO

A novel molecularly imprinted polymer (MIP) using the specific ionic liquid (i.e. 1-vinyl-3-carboxymethylimidazolium bromide, 1-vinyl-3-carboxyethylimidazolium bromide, 1-viny-3-carboxybutylimidazolium bromide, or 1-vinyl-3-carboxypentylimidazolium bromide) as functional monomer was prepared via precipitation polymerization, which can be used to selectively separate synephrine (SYN) from methanol-water media. Ionic liquids are facile to be designed with varying the cation or anion, which enables the specific ionic liquid to be effectively designed to be a functional monomer for the preparation of MIP. The MIP showed a good selectivity and high adsorption capacity for SYN in methanol-water media. The adsorption process could be described by the pseudo-first-order model, which meant that the adsorption kinetics described a diffusion-controlled process. The equilibrium data fitted well to the Freundlich model, indicating multilayer adsorption. Finally, the MIP were successfully applied as sorbent to selectively enrich and separate SYN from the extracts of Aurantii Fructus Immaturus with a relatively high recovery (80-90%).


Assuntos
Citrus/química , Medicamentos de Ervas Chinesas/isolamento & purificação , Líquidos Iônicos/química , Polímeros/química , Extração em Fase Sólida/métodos , Sinefrina/isolamento & purificação , Adsorção , Medicamentos de Ervas Chinesas/química , Impressão Molecular , Polímeros/síntese química , Extração em Fase Sólida/instrumentação , Sinefrina/química
2.
Food Chem ; 135(4): 2299-306, 2012 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-22980805

RESUMO

Ionic liquid (IL) based ultrasonic assisted extraction (ILUAE) was developed for the effective extraction of puerarin from Radix Puerariae Lobatae (RPL). The ILUAE parameters including the type of ILs, IL concentration, RPL amount, ultrasonic power and time were optimized by single-factor experiment and response surface methodology. Under the optimized experimental conditions, the best results were obtained using RPL amount 0.43 g in 10 mL 1.06 molL(-1) 1-butyl-3-methylimidazolium bromide aqueous solution, ultrasonic time 27.43 min and ultrasonic power 480 W. Scanning electron microscope images of RPL samples were obtained to provide visual evidence of the sonication effect. Compared with the conventional ultrasonic assisted extraction and refluent extraction, the proposed ILUAE offered shorter extraction time and remarkable higher efficiencies due to the higher penetration ability and solubility of IL and the cavitation phenomenon produced in the solvent by the passage of an ultrasonic wave, which further supported the suitability of the proposed approach.


Assuntos
Fracionamento Químico/métodos , Isoflavonas/isolamento & purificação , Pueraria/química , Ultrassom/métodos , Fracionamento Químico/instrumentação , Cromatografia Líquida de Alta Pressão , Líquidos Iônicos , Isoflavonas/análise
3.
Anal Bioanal Chem ; 402(3): 1337-46, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22086397

RESUMO

In this work, molecularly imprinted solid-phase extraction (MISPE) has been used to selectively enrich, purify, or remove synephrine from Aurantii Fructus Immaturus. To this end, a molecularly imprinted polymer (MIP) was prepared by self-assembly from the template synephrine, the functional monomer methacrylic acid, and the crosslinker ethylene glycol dimethacrylate in 1:4:20 molar ratio. Subsequent molecular interrogation of the MIP binding sites revealed preferential structural selectivity for synephrine relative to other structurally related naturally occurring compounds (i.e. octopamine and tyramine ). This selectivity was subsequently exploited to achieve substantial sample clean-up of extracts of crude Aurantii Fructus Immaturus and Aurantii Fructus Immaturus stir-baked with bran. The purity of synephrine in the extracts after MISPE represented approximately 24.21-fold enrichment of the synephrine in the untreated extracts of Aurantii Fructus Immaturus stir-baked with bran. High recoveries (85-90%) from the samples proved that the method was valid for selective enrichment, purification, or removal of synephrine from Aurantii Fructus Immaturus.


Assuntos
Citrus/química , Metacrilatos/química , Impressão Molecular , Extratos Vegetais/isolamento & purificação , Extração em Fase Sólida/métodos , Sinefrina/isolamento & purificação , Calibragem , Limite de Detecção , Impressão Molecular/métodos , Polimerização
4.
J Basic Microbiol ; 52(3): 360-7, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21780146

RESUMO

The propionyl-CoA dehydrogenase (PACD) gene was cloned from Candida rugosa by the cDNA RACE technique. The full cDNA of the PACD gene has a length of 1408 bp, which contains a complete open reading frame (ORF) of 1329 bp, coding for 442 amino acids. The cDNA of PACD was cloned into the expression plasmid pPIC9K and transformed into Pichia pastoris GS115. The recombinant protein was purified by Ni-NTA affinity chromatography, and its size was observed to be approximately 49 kDa as estimated by SDS-PAGE. Anti-His antibodies were used to characterise the recombinant PACD by western-blot analysis. The recombinant protein retained the activity of catalysing propionyl-CoA to acryloyl-CoA. The results of dot-blotting hybridisation using a PACD cDNA probe indicated that the PACD mRNA level was modified at different stages: mRNA levels were low for the first 36 h, then increased through 48 h and eventually reached a stable level. These results indicate that propionate induction could significantly activate PACD mRNA expression. Information from this study will be helpful in elucidating the metabolic pathway for 3-hydroxypropionic acid production in C. rugosa.


Assuntos
Acil Coenzima A/metabolismo , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Candida/enzimologia , Candida/genética , Transcrição Genética , Oxirredutases do Álcool/química , Sequência de Aminoácidos , Sequência de Bases , Western Blotting , Cromatografia de Afinidade , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Expressão Gênica , Perfilação da Expressão Gênica , Vetores Genéticos , Dados de Sequência Molecular , Peso Molecular , Fases de Leitura Aberta , Pichia/genética , Plasmídeos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo
5.
Bioresour Technol ; 102(11): 6458-63, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21507630

RESUMO

The objective of this work was to examine the feasibility of biogas production from the anaerobic co-digestion of herbal-extraction residues with swine manure. Batch and semi-continuous experiments were carried out under mesophilic anaerobic conditions. Batch experiments revealed that the highest specific biogas yield was 294 mL CH(4) g(-1) volatile solids added, obtained at 50% of herbal-extraction residues and 3.50 g volatile solids g(-1) mixed liquor suspended solids. Specific methane yield from swine manure alone was 207 mL CH(4) g(-1) volatile solid added d(-1) at 3.50 g volatile solids g(-1) mixed liquor suspended solids. Furthermore, specific methane yields were 162, 180 and 220 mL CH(4) g (-1) volatile solids added d(-1) for the reactors co-digesting mixtures with 10%, 25% and 50% herbal-extraction residues, respectively. These results suggested that biogas production could be enhanced efficiently by the anaerobic co-digestion of herbal-extraction residues with swine manure.


Assuntos
Biocombustíveis/análise , Biotecnologia/métodos , Esterco/análise , Extratos Vegetais/química , Anaerobiose , Análise de Variância , Animais , Estudos de Viabilidade , Metano/biossíntese , Análise de Regressão , Sus scrofa
6.
J Chromatogr A ; 1147(1): 127-34, 2007 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-17328902

RESUMO

The feasibility and generic applicability of directly integrating conventional discrete operations of cell disruption by high pressure homogenizer and the product capture by aqueous two-phase extraction (ATPE) system have been demonstrated for the extraction of intracellular L-asparaginase from E. coli. In a side-by-side comparison with the conventional ATPE process, including cell disruption, centrifugal clarification and following ATPE, purification of L-asparaginase via this novel in situ ATPE process yielded a product of L-asparaginase with a higher specific activity of 94.8 U/(mg protein) and a higher yield of 73.3%, both of which in the conventional ATPE process were 78.6 U/(mg protein) and 52.1%, respectively. In the purification of L-asparaginase (pI=4.9), product-debris interactions commonly diminish its recovery. It was demonstrated that immediate extraction of L-asparaginase in ATPE systems when it is released at pH 5.0 during cell disruption effectively increased its recovery in the top phase due to the reduced interaction between L-asparaginase and cell debris and the reduced degradation by contaminated protease. In addition, no clarification step and/or disruptate storage are required in this in situ ATPE, which reduced the number of unit operations and thus shortened the overall process time. This novel process has a good potential for the separation of other intracellular biological products.


Assuntos
Asparaginase/isolamento & purificação , Biotecnologia/métodos , Extratos Celulares/isolamento & purificação , Polietilenoglicóis/química , Proteínas Recombinantes/isolamento & purificação , Asparaginase/biossíntese , Reatores Biológicos , Fracionamento Celular/métodos , Escherichia coli/classificação , Escherichia coli/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Proteínas/isolamento & purificação , Temperatura
7.
J Hazard Mater ; 135(1-3): 94-9, 2006 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-16343762

RESUMO

Alachlor can be recalcitrant when present at high concentrations in wastewater. Ferrate oxidation was used as a pretreatment to improve its biodegradability and was evaluated by monitoring alachlor elimination and removal of COD(Cr) (chemical oxygen demand determined by potassium dichromate) during the oxidation process up to a value compatible with biological treatment. Ferrate oxidation resulted in elimination of alachlor followed by degradation of its intermediates. High pH suppressed alachlor removal and COD(Cr) removal due to the low redox potential of ferrate ions. Although alachlor can be totally eliminated within 10 min under optimized conditions (alachlor, 40 mg l(-1); ferrate:alachlor molar ratio, 2; and pH 7.0), its complete mineralization cannot be achieved by ferrate oxidation alone. Alachlor solution treated by ferrate for 10 min inhibited an up-flow biotreatment with activated sludge. The biodegradability of ferrate-pretreated solution improved when the treatment was increased to 20 min, at the point of which BOD(5)/COD(Cr) ratio of the treated solution was increased to 0.87 from 0.35 after 10 min treatment. Under optimized conditions, ferrate oxidation for 20 min resulted in total elimination of alachlor, partial removal of COD(Cr) and the ferrate-treated solution could be effectively treated by the up-flow activated sludge process.


Assuntos
Acetamidas/metabolismo , Ferro/metabolismo , Reatores Biológicos , Concentração de Íons de Hidrogênio , Oxirredução , Esgotos
8.
J Biotechnol ; 117(4): 355-65, 2005 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-15925718

RESUMO

A new class of microcapsules was prepared under physiological conditions by polyelectrolyte complexation between two oppositely-charged, water-soluble polymers. The microcapsules consisted of an inner core of half N-acetylated chitosan and an outer shell of methacrylic acid (MAA) (20.4%)-hydroxyethyl methacrylate (HEMA) (27.4%)-methyl methacrylate (MMA) (52.2%) (MAA-HEMA-MMA) terpolymer. Both 400 and 150 kDa half N-acetylated chitosans maintained good water solubility and supplied enough protonated amino groups to coacervate with terpolymer at pH 7.0-7.4, in contrast to other chitosan-based microcapsules which must be prepared at pH <6.5. The viscosity of half N-acetylated chitosan solutions between 80 and 3000 cPas allowed the formation of microcapsules with spherical shape. Molar mass, pH and concentration of half N-acetylated chitosan, and reaction time, influenced the morphology, thickness and porosity of the microcapsules. Microcapsules formed with high concentration of half N-acetylated chitosan exhibited improved mechanical stability, whereas microcapsules formed with low concentration of half N-acetylated chitosan exhibited good permeability. This 3D microenvironment has been configured to cultivate sensitive anchorage-dependent cells such as hepatocytes to maintain high level of functions.


Assuntos
Materiais Biocompatíveis/química , Técnicas de Cultura de Células/métodos , Quitosana/química , Hepatócitos/citologia , Hepatócitos/fisiologia , Ácidos Polimetacrílicos/química , Engenharia Tecidual/métodos , Água/química , Animais , Células Cultivadas , Masculino , Teste de Materiais , Microesferas , Tamanho da Partícula , Permeabilidade , Ratos , Ratos Wistar , Solubilidade , Resistência à Tração
9.
Colloids Surf B Biointerfaces ; 43(1): 1-6, 2005 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-15885992

RESUMO

Multilayer films of amphoteric methylated collagen were assembled on SOURCE 15S or SOURCE 15Q beads by sequential electrostatic deposition with negatively charged methylacrylic acid-hydroxyethyl methacrylate-methyl methacrylate (MAA-HEMA-MMA) terpolymer. Methylated collagen and terpolymer were deposited under conditions where they were oppositely charged to one another, thereby facilitating growth of the films through electrostatic interactions. Measurements revealed alternating positive and negative zeta-potential with the deposition of each methylated collagen and terpolymer layer, respectively. Assembly pH had a remarkable influence on zeta-potential of the assembled multilayers and the deposition of methylated collagen will be frustrated when the assembly pH is up to 9.0. In addition, ionic strength (NaCl concentration) showed an intricate effect on zeta-potential of the films of amphoteric methylated collagen.


Assuntos
Colágeno/química , Potenciais da Membrana , Membranas Artificiais , Concentração de Íons de Hidrogênio , Metanol/química , Eletricidade Estática , Propriedades de Superfície , Engenharia Tecidual/métodos
10.
Biomaterials ; 26(16): 3153-63, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15603810

RESUMO

Hepatocytes are anchorage-dependent cells sensitive to microenvironment; the control of the physicochemical properties of the extra-cellular matrices may be useful to the maintenance of hepatocyte functions in vitro for various applications. In a microcapsule-based 3-D hepatocyte culture microenvironment, we could control the physical properties of the collagen nano-fibres by fine-tuning the complex-coacervation reaction between methylated collagen and terpolymer of hydroxylethyl methacrylate-methyl methacrylate-methylacrylic acid. The physical properties of the nano-fibres were quantitatively characterized using back-scattering confocal microscopy to help optimize the physical support for hepatocyte functions. We further enhanced the chemical properties of the collagen nano-fibres by incorporating galactose onto collagen, which can specifically interact with the asialoglycoprotein receptor on hepatocytes. By correlating a range of collagen nano-fibres of different physicochemical properties with hepatocyte functions, we have identified a specific combination of methylated and galactosylated collagen nano-fibres optimal for maintaining hepatocyte functions in vitro. A model of how the physical and chemical supports interplay to maintain hepatocyte functions is discussed.


Assuntos
Técnicas de Cultura de Células/métodos , Matriz Extracelular/metabolismo , Hepatócitos/citologia , O-Dealquilase 7-Alcoxicumarina/química , Animais , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Colágeno/química , Galactose/química , Galactose/metabolismo , Hepatócitos/química , Hepatócitos/metabolismo , Processamento de Imagem Assistida por Computador , Masculino , Metacrilatos/química , Metilação , Metilmetacrilato/química , Microcirculação , Microscopia Confocal , Modelos Químicos , Polímeros/química , Ratos , Ratos Wistar , Espalhamento de Radiação
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