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1.
Arq. bras. med. vet. zootec. (Online) ; 72(1): 215-223, Jan.-Feb. 2020. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1088940

RESUMO

The objective of this study was to evaluate the metabolic response of native lambs fed Tifton 85 hay (Cynodon dactylon) or Maniçoba hay (Manihot pseudoglaziovii) associated with spineless cactus (Nopalea cochenillifera Salm Dyck). Sixteen Morada Nova lambs were used, with a mean initial weight of 19.36±1.48kg, distributed in a randomized block design, with two treatments and eight replications. Dry matter intake was higher for lambs fed Maniçoba hay compared to Tifton hay, while the body weight at slaughter was not influenced by diets. Regarding the blood metabolites, only the serum concentration of urea was influenced, with higher value observed in the lambs that fed the diet containing Tifton hay. When analyzing blood biomarkers, in the different biweekly collections, a linear increase in the blood concentration of urea, glucose, fructosamine, alkaline phosphatase and sodium was observed, as well as a quadratic effect for serum potassium. The other blood metabolites were not influenced in function of the collection days. The replacement of Tifton 85 hay for Maniçoba hay does not cause negative changes in the dynamics of different biomarkers and presents itself as a promising forage resource.(AU)


O objetivo deste trabalho foi avaliar a resposta metabólica de cordeiros nativos alimentados com feno de capim-tifton 85 (Cynodon dactylon) ou feno de maniçoba (Manihot pseudoglaziovii) associados à palma forrageira (Nopalea cochenillifera Salm Dyck). Foram utilizados 16 cordeiros Morada Nova, com peso inicial médio de 19,36±1,48kg, distribuídos em delineamento de blocos ao acaso, com dois tratamentos e oito repetições. O consumo de matéria seca foi maior nos cordeiros alimentados com feno de maniçoba em comparação ao feno de tifton, enquanto o peso corporal ao abate não foi influenciado pelas dietas. Em relação aos metabólitos sanguíneos, apenas a concentração sérica de ureia foi influenciada, com maior valor observado nos cordeiros que ingeriram a dieta contendo feno de capim-tifton. Quando foi realizada a análise dos biomarcadores sanguíneos nas diferentes coletas quinzenais, foi observado aumento linear nas concentrações sanguíneas de ureia, glicose, frutosamina, fosfatase alcalina e sódio, e efeito quadrático para o potássio sérico. Os demais metabólitos sanguíneos não foram influenciados em função dos dias de coleta. A substituição do feno de tifton 85 por feno de maniçoba influencia positivamente o metabolismo de cordeiros sem causar alterações na dinâmica dos diferentes biomarcadores e se apresenta como um promissor recurso forrageiro.(AU)


Assuntos
Animais , Ovinos/metabolismo , Biomarcadores , Manihot , Cactaceae , Cynodon
2.
Braz. j. biol ; 79(1): 133-138, Jan.-Mar 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-984010

RESUMO

Abstract Length and weight relationships and descriptive statistics are reported for six shrimp species caught off the Madeira archipelago between 1983 and 2014 using bottom and floating traps from depths ranging from 50 to 1,300 m. The parameter b ranged between 2.36 for Plesionika ensis and 2.97 for Plesionika williamsi. All species showed a pattern of negative allometric growth. To the authors' knowledge all weight-length relationships presented herein are recorded for the first time from the Madeira area, and in the cases of Ligur ensiferus and Plesionika ensis are the first references worldwide.


Resumo As relações peso-comprimento e a estatística descritiva foram estimadas para seis espécies de camarões, capturados ao largo do arquipélago da Madeira, entre 1983 e 2014, usando armadilhas de fundo e alvoradas entre os 50 e 1.300 metros de profundidade. O parâmetro b variou entre 2,36 para Plesionika ensis e 2,97 para Plesionika williamsi. Todas as espécies evidenciaram um padrão de crescimento alométrico negativo. De acordo com o conhecimento dos autores, todas as relações peso-comprimento são aqui apresentadas pela primeira vez para a área da Madeira e no caso de Ligur ensiferus e Plesionika ensis são a primeira referência mundial.


Assuntos
Animais , Masculino , Feminino , Decápodes/fisiologia , Portugal , Peso Corporal , Oceano Atlântico , Pandalidae/fisiologia , Tamanho Corporal
3.
Braz J Biol ; 79(1): 133-138, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29694561

RESUMO

Length and weight relationships and descriptive statistics are reported for six shrimp species caught off the Madeira archipelago between 1983 and 2014 using bottom and floating traps from depths ranging from 50 to 1,300 m. The parameter b ranged between 2.36 for Plesionika ensis and 2.97 for Plesionika williamsi. All species showed a pattern of negative allometric growth. To the authors' knowledge all weight-length relationships presented herein are recorded for the first time from the Madeira area, and in the cases of Ligur ensiferus and Plesionika ensis are the first references worldwide.


Assuntos
Decápodes/fisiologia , Animais , Oceano Atlântico , Tamanho Corporal , Peso Corporal , Feminino , Masculino , Pandalidae/fisiologia , Portugal
4.
J Microencapsul ; 35(4): 344-356, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29889598

RESUMO

Pharmaceutical research has been focussed on developing improved delivery systems while exploring new ways of using approved excipients. The present work investigated the potential of starch nanocapsules (StNC) as a topical delivery platform for hydrophilic antimicrobial drugs using minocycline hydrochloride (MH) as a model drug. Thus, a quality by design approach was used to assess the role of different factors that affect the main pharmaceutical properties of StNC prepared using an emulsification-solvent evaporation method. Full characterisation was performed in terms of particle size, encapsulation efficiency, morphology and physical stability at 5 ± 3 °C. Results show the surfactant and lipid contents play a major role in StNC particle size distribution. The MH loading only promoted minor changes upon StNC properties. Formulations were stable without variations on physicochemical properties. All tested formulations presented a zeta-potential of +33.6 ± 6.7 mV, indicating a good physical stability and evidencing that StNC are suitable nanocarriers for topical use.


Assuntos
Antibacterianos/administração & dosagem , Minociclina/administração & dosagem , Nanocápsulas/química , Amido/química , Administração Tópica , Antibacterianos/química , Composição de Medicamentos , Estabilidade de Medicamentos , Excipientes/química , Interações Hidrofóbicas e Hidrofílicas , Minociclina/química , Tamanho da Partícula , Solubilidade , Tensoativos/química
5.
Aliment Pharmacol Ther ; 48(5): 507-522, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29873091

RESUMO

AIM: To test the cross-immunogenicity of anti-CT-P13 IBD patients' sera to CT-P13/infliximab originator and the comparative antigenicity evoked by CT-P13/infliximab originator sera. METHODS: Sera of patients with IBD with measurable anti-CT-P13 antibodies were tested for their cross-reactivity to 5 batches of infliximab originator and CT-P13. Anti-drug antibody positive sera from treated patients were used to compare antigenic epitopes. RESULTS: All 42 anti-CT-P13 and 37 anti-infliximab originator IBD sera were cross-reactive with infliximab originator and CT-P13 respectively. Concentration of anti-drug antibodies against infliximab originator or CT-P13 were strongly correlated both for IgG1 and IgG4 (P < 0.001). Anti-CT-P13 sera of patients with IBD (n = 32) exerted similar functional inhibition on CT-P13 or infliximab originator TNF binding capacity and showed reduced binding to CT-P13 in the presence of five different batches of CT-P13 and infliximab originator. Anti-CT-P13 and anti-infliximab originator IBD sera selectively enriched phage-peptides from the VH (CDR1 and CDR3) and VL domains (CDR2 and CDR3) of infliximab. Sera reactivity detected major infliximab epitopes in these regions of infliximab in 60%-79% of patients, and no significant differences were identified between CT-P13 and infliximab originator immunogenic sera. Minor epitopes were localised in framework regions of infliximab with reduced antibody reactivity shown, in 30%-50% of patients. Monoclonal antibodies derived from naïve individuals and ADA-positive IBD patients treated with CT-P13 provided comparable epitope specificity to five different batches of CT-P13 and infliximab originator. CONCLUSIONS: These results strongly support a similar antigenic profile for infliximab originator and CT-P13, and point toward a safe switching between the two drugs in anti-drug antibody negative patients.


Assuntos
Anticorpos Monoclonais/imunologia , Epitopos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/imunologia , Infliximab/imunologia , Anticorpos Monoclonais/análise , Anticorpos Monoclonais/química , Anticorpos Monoclonais/uso terapêutico , Medicamentos Biossimilares/uso terapêutico , Estudos de Casos e Controles , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Epitopos/imunologia , Humanos , Imunoglobulina G/análise , Imunoglobulina G/sangue , Imunoglobulina G/química , Infliximab/uso terapêutico , Biblioteca de Peptídeos
6.
Eur J Pharm Biopharm ; 127: 1-11, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29409864

RESUMO

Psoriasis and atopic dermatitis patients show an excessive amount of elastase in peripheral blood neutrophils due to an imbalance between this proteolytic enzyme and its endogenous inhibitors, the search for new human neutrophil elastase (HNE) inhibitors are required. The HNE is an attractive therapeutic target and inhibitors with new molecular architectures have been extensively investigated. In this context a promising novel synthetic human neutrophil elastase inhibitor (ER143) was associated to a starch-based nanoparticulate system (StNC) with improved pharmaceutical performance, using a quality by design approach to support product development and optimization. The resulting formulation was characterized in terms of and in vitro release, permeation and retention studies in newborn pig skin, using Franz diffusion cells revealing the StNC have the ability to control the drug release rate and contribute to a high skin retention and/or permeation profiles. The anti-inflammatory activity accessed in vivo using the croton oil-induced ear inflammation model in mice showed that erythema and edema were attenuated in 98% following local application. These observations suggest the association of ER143 to the StNC promotes a deeper skin penetration and retention, also confirming StNC as a potential topical delivery system.


Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Nanocápsulas/química , Neutrófilos/metabolismo , Elastase Pancreática/antagonistas & inibidores , Amido/química , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Dermatite Atópica/tratamento farmacológico , Edema/tratamento farmacológico , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Permeabilidade/efeitos dos fármacos , Pele/efeitos dos fármacos , Suínos
7.
Braz. j. biol ; 77(3): 585-593, July-Sept. 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-888792

RESUMO

Abstract Several experimental surveys were carried out in the Northeastern Atlantic, Madeira archipelago from 1991 to 2008 to explore new fisheries resources. This study examined the selectivity of bottom and floating traps and the analysis of yield-per-recruit (YPR) and biomass-per-recruit (BPR) providing helpful insight to the management of the shrimp Plesionika narval. A total of 28,262 specimens were sampled and the analysis of length at first capture returned higher values when using floating traps indicating that these traps are more selective, exerting less pressure on the resource. The YPR and BPR analysis showed that the stock is under exploited for the studied area and suggests that the use of floating traps in the commercial fisheries of P. narval is recommended, which will allow a higher maximum allowable limit of exploitation and greater yield. The results suggest that P. narval has the potential to support a viable and sustainable fishery using floating traps.


Resumo Vários cruzeiros de investigação foram realizados no Atlântico Nordeste, arquipélago da Madeira entre 1991 e 2008 visando a exploração de novos recursos pesqueiros. O presente estudo contemplou a comparação da seletividade de pesca entre armadilhas de fundo e flutuantes e a análise de rendimento por recruta (YPR) e biomassa por recruta (BPR) facultando informação essencial para a gestão do camarão Plesionika narval. Um total de 28,262 especimens foram amostrados e a análise de comprimento de primeira captura retornou valores mais elevados aquando da utilização de armadilhas flutuantes, indicando que essas armadilhas são mais seletivas e exercem menos pressão sobre o recurso. A análise YPR e BPR mostrou que o estoque se encontra sob explorado para a área de estudo e recomenda a utilização de armadilhas flutuantes na pesca comercial de P. narval, que permitirão um limite máximo de exploração com rendimento superior. Os resultados sugerem que P. narval tem o potencial para suportar uma pescaria viável e sustentável mediante a utilização de armadilhas flutuantes.


Assuntos
Animais , Masculino , Feminino , Conservação dos Recursos Naturais , Pandalidae , Pesqueiros , Portugal , Traços de História de Vida
8.
Braz. j. biol ; 77(3)July-Sept. 2017.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1468389

RESUMO

Abstract Several experimental surveys were carried out in the Northeastern Atlantic, Madeira archipelago from 1991 to 2008 to explore new fisheries resources. This study examined the selectivity of bottom and floating traps and the analysis of yield-per-recruit (YPR) and biomass-per-recruit (BPR) providing helpful insight to the management of the shrimp Plesionika narval. A total of 28,262 specimens were sampled and the analysis of length at first capture returned higher values when using floating traps indicating that these traps are more selective, exerting less pressure on the resource. The YPR and BPR analysis showed that the stock is under exploited for the studied area and suggests that the use of floating traps in the commercial fisheries of P. narval is recommended, which will allow a higher maximum allowable limit of exploitation and greater yield. The results suggest that P. narval has the potential to support a viable and sustainable fishery using floating traps.


Resumo Vários cruzeiros de investigação foram realizados no Atlântico Nordeste, arquipélago da Madeira entre 1991 e 2008 visando a exploração de novos recursos pesqueiros. O presente estudo contemplou a comparação da seletividade de pesca entre armadilhas de fundo e flutuantes e a análise de rendimento por recruta (YPR) e biomassa por recruta (BPR) facultando informação essencial para a gestão do camarão Plesionika narval. Um total de 28,262 especimens foram amostrados e a análise de comprimento de primeira captura retornou valores mais elevados aquando da utilização de armadilhas flutuantes, indicando que essas armadilhas são mais seletivas e exercem menos pressão sobre o recurso. A análise YPR e BPR mostrou que o estoque se encontra sob explorado para a área de estudo e recomenda a utilização de armadilhas flutuantes na pesca comercial de P. narval, que permitirão um limite máximo de exploração com rendimento superior. Os resultados sugerem que P. narval tem o potencial para suportar uma pescaria viável e sustentável mediante a utilização de armadilhas flutuantes.

9.
Braz J Biol ; 77(3): 585-593, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27783766

RESUMO

Several experimental surveys were carried out in the Northeastern Atlantic, Madeira archipelago from 1991 to 2008 to explore new fisheries resources. This study examined the selectivity of bottom and floating traps and the analysis of yield-per-recruit (YPR) and biomass-per-recruit (BPR) providing helpful insight to the management of the shrimp Plesionika narval. A total of 28,262 specimens were sampled and the analysis of length at first capture returned higher values when using floating traps indicating that these traps are more selective, exerting less pressure on the resource. The YPR and BPR analysis showed that the stock is under exploited for the studied area and suggests that the use of floating traps in the commercial fisheries of P. narval is recommended, which will allow a higher maximum allowable limit of exploitation and greater yield. The results suggest that P. narval has the potential to support a viable and sustainable fishery using floating traps.


Assuntos
Conservação dos Recursos Naturais , Pesqueiros , Traços de História de Vida , Pandalidae , Animais , Feminino , Masculino , Portugal
10.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467167

RESUMO

Abstract Length and weight relationships and descriptive statistics are reported for six shrimp species caught off the Madeira archipelago between 1983 and 2014 using bottom and floating traps from depths ranging from 50 to 1,300 m. The parameter b ranged between 2.36 for Plesionika ensis and 2.97 for Plesionika williamsi. All species showed a pattern of negative allometric growth. To the authors knowledge all weight-length relationships presented herein are recorded for the first time from the Madeira area, and in the cases of Ligur ensiferus and Plesionika ensis are the first references worldwide.


Resumo As relações peso-comprimento e a estatística descritiva foram estimadas para seis espécies de camarões, capturados ao largo do arquipélago da Madeira, entre 1983 e 2014, usando armadilhas de fundo e alvoradas entre os 50 e 1.300 metros de profundidade. O parâmetro b variou entre 2,36 para Plesionika ensis e 2,97 para Plesionika williamsi. Todas as espécies evidenciaram um padrão de crescimento alométrico negativo. De acordo com o conhecimento dos autores, todas as relações peso-comprimento são aqui apresentadas pela primeira vez para a área da Madeira e no caso de Ligur ensiferus e Plesionika ensis são a primeira referência mundial.

11.
J Photochem Photobiol B ; 162: 56-64, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27344635

RESUMO

Green coffee oil and modified starch were recently found to have an enhanced protection effect against UV radiation. Therefore, this work aimed to develop an innovative sunscreen formulation based on Pickering emulsions concept, i.e., surfactant-free emulsions stabilized by physical UV filters associated natural oils as a key strategy for prevention against UV-induced skin damage. The Pickering emulsions of different compositions were characterized in terms of pH, mechanical, physical and microbiological stability by a thorough pharmaceutical control. In addition, the sun protection factor (SPF) as well as the in vitro and in vivo biological properties of the final formulations, including Episkin®, HRIPT and sunscreen water resistance. Formulation studies demonstrated the addition of physical UV filters was beneficial, leading to the inclusion of ZnO and TiO2 to ensure a high SPF against UVA and UVB, respectively. Although starch particles presented no intrinsic photoprotection properties, they proved to be a SPF promoter by a synergistic effect. Green coffee oil was the selected natural oil due to the highest SPF, when compared to other natural oils tested. Besides the excellent sunscreen activity confirmed by in vitro and in vivo results, the final formulations proved to be also suitable for topical use according to the rheological assessment and stability throughout the study period (3months). In conclusion, the combination of three multifunctional solid particles and green coffee oil, contributed to achieve a stable and effective innovative sunscreen with a wide range of UV radiation protection.


Assuntos
Emulsões , Amido/química , Luz Solar , Protetores Solares/química
12.
Colloids Surf B Biointerfaces ; 143: 177-185, 2016 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-27003468

RESUMO

Exploring novel applications for approved excipients with a history of safe use in therapeutics is a smart strategy to obtain improved pharmaceutical products. The present study aimed at developing a novel starch-based nanoparticulate carrier system (StNC) for topical delivery of lipophilic bioactive molecules. The role of the different factors that affect the particle size distribution and zeta potential of StNC prepared by the emulsification-solvent evaporation method was assessed using a quality by design approach. An optimal formulation was selected and fully characterized in terms of molecular interactions (DSC and FTIR), morphology (TEM and AFM), as well as in vitro and in vivo biological properties, including biological sensitivity/irritation studies performed in human volunteers. Results show the surfactant and lipid contents play a major role in StNC particle size distribution. In addition, all tested formulations presented a zeta potential of ca. +33.6±6.7 mV, indicating a good physical stability, while revealing an excellent compromise between stability, safety and cosmeticity, evidencing that StNC are suitable nanocarriers for topical use. Finally, the design planning methodology has clearly shown its usefulness for optimizing the formulation, being also crucial for the understanding of StNC formation process. The StNC proved to be a promising formulation strategy and a potential nanocarrier for topical lipophilic bioactive molecules.


Assuntos
Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos/métodos , Nanocápsulas/administração & dosagem , Amido/química , Administração Tópica , Varredura Diferencial de Calorimetria , Linhagem Celular , Portadores de Fármacos/química , Humanos , Queratinócitos/citologia , Queratinócitos/metabolismo , Lipídeos/química , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Nanocápsulas/química , Nanocápsulas/ultraestrutura , Tamanho da Partícula , Testes do Emplastro/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos/química
13.
Colloids Surf B Biointerfaces ; 135: 183-192, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26263210

RESUMO

Pickering emulsions are stabilized by solid particles instead of surfactants and have been widely investigated in pharmaceutical and cosmetic fields since they present less adverse effects than the classical emulsions. A quality by design (QbD) approach was applied to the production of w/o emulsions stabilized by starch. A screening design was conducted to identify the critical variables of the formula and the process affecting the critical quality properties of the emulsion (droplet size distribution). The optimization was made by establishing the Design Space, adjusting the concentration of starch and the quantity of the internal aqueous phase. The emulsion production process was, in turn, adjusted by varying the time and speed of stirring, to ensure quality and minimum variability. The stability was also investigated, demonstrating that an increase in starch concentration improves the stability of the emulsion. Rheological and mechanical studies indicated that the viscosity of the emulsions was enhanced by the addition of starch and, to a higher extent, by the presence of different lipids. The developed formulations was considered non-irritant, by an in vitro assay using human cells from skin (Df and HaCat) with the cell viability higher than 90% and, with self-preserving properties. Finally, the QbD approach successfully built quality in Pickering emulsions, allowing the development of hydrophilic drug-loaded emulsions stabilized by starch with desired organoleptic and structural characteristics. The results obtained suggest that these systems are a promising vehicle to be used in products for topical administration.


Assuntos
Sistemas de Liberação de Medicamentos , Excipientes/química , Amido/química , Administração Tópica , Sobrevivência Celular , Desenho de Fármacos , Emulsões , Humanos , Lipídeos , Tamanho da Partícula , Pós , Reologia , Pele/citologia , Pele/metabolismo , Viscosidade
15.
Vaccine ; 32(42): 5520-30, 2014 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-25101982

RESUMO

BACKGROUND: Immunisation of children with pneumococcal conjugate vaccines (PCV) may affect the bacterial-ecology of the nasopharynx, including colonisation by Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. The aim of this study was to evaluate the effect of infant PCV-immunisation on the nasopharyngeal ecology of these potentially pathogenic bacteria in a rural African setting. METHODS: Two cross sectional surveys were undertaken from May to October in 2009 (Period-1) which coincided with the introduction of 7-valent PCV (PCV7) and in May-October 2011 (Period-2). Consenting household members, where there was a child <2 years of age in residence, had nasopharyngeal swabs undertaken for culture. RESULTS: From Period-1 to Period-2 in children 0-2 years and 3-12 years, prevalence of overall S. pneumoniae colonisation decreased from 74.9% to 67.0% (p<0.001) and H. influenzae declined among children 3-12 years (55.1-45.3%, p<0.001) but not among those <2 years. The prevalence of S. aureus remained unchanged in all children. Competitive associations were found between S. pneumoniae and S. aureus and between H. influenzae and S. aureus among children. In individuals >12 years, the prevalence of colonisation decreased from 11.2% to 6.8%, 16.7% to 8.8% and 31.2% to 23.7% for S. pneumoniae, H. influenzae and S. aureus, respectively; p<0.001 for all comparions. Synergistic relationships for S. aureus with H. influenzae and S. pneumoniae were observed in both periods among this group.


Assuntos
Portador Sadio/epidemiologia , Haemophilus influenzae/isolamento & purificação , Vacinas Pneumocócicas/uso terapêutico , Staphylococcus aureus/isolamento & purificação , Streptococcus pneumoniae/isolamento & purificação , Adolescente , Adulto , Criança , Pré-Escolar , Estudos Transversais , Feminino , Vacina Pneumocócica Conjugada Heptavalente , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Nasofaringe/microbiologia , Infecções Pneumocócicas/prevenção & controle , População Rural , África do Sul/epidemiologia , Fatores de Tempo , Vacinas Conjugadas/uso terapêutico , Adulto Jovem
16.
Bioresour Technol ; 134: 219-26, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23500578

RESUMO

Biofuel production from microalgal biomass could be an alternative solution to conventional biofuels typically dependent on food and high land/water demanding crops. However, the economic and energetic viability of microalgal biofuels is limited by their harvesting processes. The finding of innovative, low cost and efficient harvesting method(s) is imperative. In this study, the Electro-Coagulation (EC) was studied as a process to harvest the marine Nannochloropsis sp. microalga. Several EC operational conditions were studied and the best EC recovery efficiency (>97%) was achieved using a current density of 8.3 mA cm(-2) for 10 min. The quality of the recovered microalgal biomass was evaluated in terms of total lipids, fatty acid and pigment profile where no significant differences were observed after EC treatment. The energy requirements of the harvesting process were estimated and the combination of EC and centrifugation processes proved to decrease significantly the energy demand when compared with the individual process.


Assuntos
Biocombustíveis/microbiologia , Biomassa , Técnicas Eletroquímicas/métodos , Microalgas/crescimento & desenvolvimento , Pigmentos Biológicos/biossíntese , Absorção , Alumínio/análise , Centrifugação , Eletricidade , Técnicas Eletroquímicas/instrumentação , Eletrodos , Microalgas/metabolismo , Óleos/análise , Análise Espectral , Termodinâmica , Fatores de Tempo
17.
Appl Microbiol Biotechnol ; 97(3): 1383-93, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23160982

RESUMO

Today microalgae represent a viable alternative source for high-value products. The specie Chlorella protothecoides (Cp), heterotrophically grown, has been widely studied and provides a high amount of lutein and fatty acids (FA) and has a good profile for biodiesel production. This work studies carotenoid and FA production by autotrophic grown Cp. Cp was grown until the medium's nitrogen was depleted, then diluted in NaCl solution, resulting in nutritional, luminosity, and salinity stresses. Different NaCl concentrations were tested (10, 20, 30 g/L) at two different dilutions. After dilution, a color shifting from green to orange-red was noticed, showing carotenoid production. The best production of both carotenoids and FA was attained with a 20 g/L NaCl solution. The total carotenoid content was 0.8 % w/w (canthaxanthin (23.3 %), echinenone (14.7 %), free astaxanthin (7.1 %), and lutein/zeaxanthin (4.1 %)). Furthermore, the total lipid content reached 43.4 % w/w, with a FA composition of C18:1 (33.64 %), C16:0 (23.30 %), C18:2 (11.53 %), and less than 12 % of C18:3, which is needed to fulfill the biodiesel quality specifications (EN 14214).


Assuntos
Carotenoides/metabolismo , Chlorella/metabolismo , Luz , Metabolismo dos Lipídeos , Salinidade , Estresse Fisiológico , Biocombustíveis , Chlorella/efeitos dos fármacos , Chlorella/fisiologia , Chlorella/efeitos da radiação , Cor , Fermentação , Cloreto de Sódio/metabolismo
18.
Bioresour Technol ; 135: 128-36, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23265815

RESUMO

The microalga Nannochloropsis sp. was used in this study, in a biorefinery context, as biomass feedstock for the production of fatty acids for biodiesel, biohydrogen and high added-value compounds. The microalgal biomass, which has a high lipid and pigment content (mainly carotenoids), was submitted to supercritical CO2 extraction. The temperature, pressure and solvent flow-rate were evaluated to check their effect on the extraction yield. The best operational conditions to extract 33 g lipids/100 g dry biomass were found to be at 40 °C, 300 bar and a CO2 flow-rate of 0.62 g/min. The effect of adding a co-solvent (ethanol) was also studied. When supercritical CO2 doped with 20% (w/w) ethanol was used, it was possible to extract 45 g lipids/100 g dry biomass of lipids and recover 70% of the pigments. Furthermore, the remaining biomass after extraction was effectively used as feedstock to produce biohydrogen through dark fermentation by Enterobacter aerogenes resulting in a hydrogen production yield of 60.6 mL/g dry biomass.


Assuntos
Biocombustíveis/microbiologia , Biomassa , Biotecnologia/métodos , Hidrogênio/metabolismo , Microalgas/metabolismo , Óleos/isolamento & purificação , Pigmentos Biológicos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Cromatografia com Fluido Supercrítico , Fermentação , Lipídeos/análise , Solventes/química
19.
Appl Microbiol Biotechnol ; 96(2): 555-64, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22899495

RESUMO

A closed-loop vertical tubular photobioreactor (PBR), specially designed to operate under conditions of scarce flat land availability and irregular solar irradiance conditions, was used to study the potential of Scenedesmus obliquus biomass/sugar production. The results obtained were compared to those from an open-raceway pond and a closed-bubble column. The influence of the type of light source and the regime (natural vs artificial and continuous vs light/dark cycles) on the growth of the microalga and the extent of the sugar accumulation was studied in both PBRs. The best type of reactor studied was a closed-loop PBR illuminated with natural light/dark cycles. In all the cases, the relationship between the nitrate depletion and the sugar accumulation was observed. The microalga Scenedesmus was cultivated for 53 days in a raceway pond (4,500 L) and accumulated a maximum sugar content of 29 % g/g. It was pre-treated for carrying out ethanol fermentation assays, and the highest ethanol concentration obtained in the hydrolysate fermented by Kluyveromyces marxianus was 11.7 g/L.


Assuntos
Metabolismo dos Carboidratos/efeitos da radiação , Etanol/metabolismo , Microalgas/metabolismo , Microalgas/efeitos da radiação , Fotobiorreatores/microbiologia , Scenedesmus/metabolismo , Scenedesmus/efeitos da radiação , Biomassa , Meios de Cultura/metabolismo , Fermentação/efeitos da radiação , Luz , Microalgas/crescimento & desenvolvimento , Scenedesmus/crescimento & desenvolvimento
20.
Bioresour Technol ; 104: 342-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22093974

RESUMO

The present work deals with the optimization of cellular disruption and sugar extraction from the microalgae Scenedesmus obliquus (Sc) for bioethanol production. Among the physical and physicochemical methods tested, the best results were obtained with acid hydrolysis by H(2)SO(4) (2N), at 120 °C for 30 min and using dried biomass. The sugar extraction efficiency level reached was 95.6% when compared to the harsh quantitative acid hydrolysis. The influence of other parameters such as biomass loading and number of extraction cycles were also evaluated. The results obtained in the latter case showed that a unique hydrolysis step is sufficient.


Assuntos
Biocombustíveis/microbiologia , Carboidratos/química , Fracionamento Celular/métodos , Etanol/metabolismo , Scenedesmus/química , Scenedesmus/metabolismo , Ácidos Sulfúricos/química , Scenedesmus/classificação , Especificidade da Espécie
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