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1.
3 Biotech ; 14(6): 163, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38808300

RESUMO

The use of new materials in the field of biofuel production has been represented as a step in the development of remarkable catalysts. The use of lipases in the production of biodiesel is often seen as a cost-limiting step, as the operating expenses in recovering such catalysts can lead to unfeasible market expectations. In this study, hydroxyapatite (HAp) particles were evaluated as a support to immobilize commercial lipase, following application in ethyl ester synthesis. First, hydroxyapatite was synthesized through the co-precipitation method at constant pH and selected as a support to be used in enzyme immobilization. The characterization of the biocatalyst support materials produced was carried out using DRX, BET, FTIR, TGA, and SEM analysis. The lipase from Thermomyces lanuginosus was then immobilized in the matrices, and, subsequently, there was transesterification of the vegetable oil deodorization distillate (VODD). The biodiesel samples generated showed that they were within commercial standards, achieving ester conversion greater than 96.5%. Other properties such as density (0.87 g.cm-3) and viscosity (4.36 mm2.s-1) meet the specifications required by ASTM to be used as a biofuel. In the experiment planning technique, the results revealed an experimental trend and a defined behavior: a higher lipase loading in the immobilization and the use of temperatures in the range of 40-50 °C favor high conversions of ethyl esters. Thus, this confirms that the enzymatic chemical catalyst was able to form the main fatty acid esters even using a residual lipid raw material.

2.
J Dev Econ ; 99(2): 330-340, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22962514

RESUMO

Conflict between and within countries can have lasting health and economic consequences, but identifying such effects can be empirically challenging. This paper uses household survey data from Eritrea to estimate the effect of exposure to the 1998-2000 Eritrea-Ethiopia war on children's health. The identification strategy exploits exogenous variation in the conflict's geographic extent and timing and the exposure of different birth cohorts to the fighting. The unique survey data include details on each household's migration history, which allows us to measure a child's geographic location during the war and without which war exposure would be incorrectly classified. War-exposed children have lower height-for-age Z-scores, with similar effects for children born before or during the war. Both boys and girls who are born during the war experience negative impacts due to conflict. Effects are robust to including region-specific time trends, alternative conflict exposure measures, and mother fixed effects.

3.
J Pharm Biomed Anal ; 48(4): 1090-5, 2008 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-18845411

RESUMO

Carapa guianensis crabwood, popularly known in Brazil as "andiroba", is a tree that grows in South and Central America and is used by the local population mainly for its anti-inflammatory and insect anti-feeding activities. Scientific studies on this plant have led to the development of an insect-repellent candle and the investigations of the anti-inflammatory properties of its more important biomarkers-tetranortriterpenoids. These compounds, together with glycerides and fatty acids, are present in the seed oil, the most important commercial product from this plant. The growing scientific and commercial interest in "andiroba oil" has urged the development of adequate analytical methods for assessing its quality. Central composite experimental design is a useful statistical method for the development and optimization of HPLC methods, and has been used for a variety of samples. The aim of this work is to develop a HPLC method for the determination of tetranortriterpenoids in "andiroba" oil, by means of central composite experimental design, as well as to prevalidate this method.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Limoninas/análise , Meliaceae/química , Óleos de Plantas/química , Projetos de Pesquisa , Sementes/química , Calibragem , Limoninas/química , Limoninas/isolamento & purificação , Estrutura Molecular , Reprodutibilidade dos Testes
4.
Bol. latinoam. Caribe plantas med. aromát ; 20(4): 386-393, jul. 2021. ilus
Artigo em Inglês | LILACS | ID: biblio-1352337

RESUMO

Leaves of Monteverdia ilicifolia ("espinheira-santa") are considered a medicinal tea by the Brazilian Sanitary Surveillance Agency (Anvisa), by their anti-dyspeptic, anti-acid and protective of the gastric mucosa properties. Their spiny margins are similar to those of other botanical species, which may lead to misidentifications. The aim of this work was to evaluate the authenticity of 32 samples of herbal drugs commercialized as "espinheira-santa" in the formal trade in Brazil, by macro and microscopic morphological studies of the leaves. The evaluation of the botanical authenticity was based on leaf venation patterns, shape and anatomy of the petiole and midrib region in cross section, vascular system arrangement and epidermal characters. Analysis of these characters compared to literature data suggests that 34% of the samples are M. ilicifolia and the remaining 66% are Sorocea bonplandii, a species with no clinical studies assuring its effective and safe use, representing thus a potential risk to public health.


Las hojas de Monteverdia ilicifolia ("espinheira-santa") son consideradas tés medicinales por la Agencia Nacional de Vigilancia Sanitaria (Anvisa), Brasil, por las indicaciones terapéuticas como antidispépticos, antiácidos y protectores de la mucosa gástrica. Sus márgenes foliares espinescentes se parecen a los de otras especies, conduciendo a identificaciones erróneas. El objetivo de este trabajo fue evaluar la autenticidad de 32 muestras de drogas vegetales vendidas como "espinheira-santa" en el comercio legal de Brasil, realizando un estudio morfológico de las hojas. Esta evaluación se ha basado en observar de la hoja, sus patrones de nerviación, su forma y anatomía (pecíolo y nervadura central en corte transversal), disposición del sistema vascular y caracteres epidérmicos. El análisis de la morfología, comparado con los datos de literatura, sugiere que el 34% de las muestras son M. ilicifoliay el 66% son Sorocea bonplandii, una especie que no cuenta con los estudios clínicos que garantizan su uso efectivo y seguro, representando un riesgo para la salud pública.


Assuntos
Plantas Medicinais , Maytenus/anatomia & histologia , Fraude , Controle de Qualidade , Brasil , Contaminação de Medicamentos , Folhas de Planta/anatomia & histologia , Celastraceae/anatomia & histologia
5.
Braz J Microbiol ; 44(4): 1075-80, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24688495

RESUMO

Perillyl derivatives are increasingly important due to their flavouring and antimicrobial properties as well as their potential as anticancer agents. These terpenoid species, which are present in limited amounts in plants, may be obtained via bioconversion of selected monoterpene hydrocarbons. In this study, seventeen yeast strains were screened for their ability to oxidize the exocyclic methyl group in the p-menthene moiety of limonene into perillic acid. Of the yeast tested, the highest efficiency was observed for Yarrowia lipolytica ATCC 18942. The conversion of R (+)-limonene by Y. lipolytica was evaluated by varying the pH (3 to 8) and the temperature (25 to 30 °C) in a reaction medium containing 0.5% v/v limonene and 10 g/L of stationary phase cells (dry weight). The best results, corresponding to 564 mg/L of perillic acid, were obtained in buffered medium at pH 7.1 that was incubated at 25 °C for 48 h. The stepwise addition of limonene increased the perillic acid concentration by over 50%, reaching 855 mg/L, whereas the addition of glucose or surfactant to the reaction medium did not improve the bioconversion process. The use of Y. lipolytica showed promise for ease of further downstream processing, as perillic acid was the sole oxidised product of the bioconversion reaction. Moreover, bioprocesses using safe and easy to cultivate yeast cells have been favoured in industry.


Assuntos
Cicloexenos/metabolismo , Monoterpenos/metabolismo , Terpenos/metabolismo , Yarrowia/metabolismo , Biotransformação , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Limoneno , Oxirredução , Temperatura
6.
Braz. j. microbiol ; 44(4): 1075-1080, Oct.-Dec. 2013. ilus, tab
Artigo em Inglês | LILACS | ID: lil-705285

RESUMO

Perillyl derivatives are increasingly important due to their flavouring and antimicrobial properties as well as their potential as anticancer agents. These terpenoid species, which are present in limited amounts in plants, may be obtained via bioconversion of selected monoterpene hydrocarbons. In this study, seventeen yeast strains were screened for their ability to oxidize the exocyclic methyl group in the p-menthene moiety of limonene into perillic acid. Of the yeast tested, the highest efficiency was observed for Yarrowia lipolytica ATCC 18942. The conversion of R (+)-limonene by Y. lipolytica was evaluated by varying the pH (3 to 8) and the temperature (25 to 30 ºC) in a reaction medium containing 0.5% v/v limonene and 10 gµL of stationary phase cells (dry weight). The best results, corresponding to 564 mgµL of perillic acid, were obtained in buffered medium at pH 7.1 that was incubated at 25 ºC for 48 h. The stepwise addition of limonene increased the perillic acid concentration by over 50%, reaching 855 mgµL, whereas the addition of glucose or surfactant to the reaction medium did not improve the bioconversion process. The use of Y. lipolytica showed promise for ease of further downstream processing, as perillic acid was the sole oxidised product of the bioconversion reaction. Moreover, bioprocesses using safe and easy to cultivate yeast cells have been favoured in industry.


Assuntos
Cicloexenos/metabolismo , Monoterpenos/metabolismo , Terpenos/metabolismo , Yarrowia/metabolismo , Biotransformação , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Oxirredução , Temperatura
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