Consulta: subjectFacets:"Alginate"
Registros recuperados: 20
Data/hora: 08/06/2024 17:59:25

An effective device for generating alginate microcapsules
Provedor de dados: 74
Autores: Bressel,Tatiana A.B.; Paz,Ana Helena; Baldo,Guilherme; Lima,Elizabeth O. Cirne; Matte,Ursula; Saraiva-Pereira,Maria Luiza.
An alternative approach to somatic gene therapy is to deliver the therapeutic protein by implanting genetically modified cells that could overexpress the gene of interest. Microencapsulation devices were designed to protect cells from host rejection and prevent the foreign cells from spreading while allowing protein secretion. Alginate microcapsules form a semi-permeable structure that is suitable for in vivo injection. In this study, we report an effective laboratory protocol for producing calcium alginate microcapsules, following optimization of uniformly shaped and sized particles containing viable cells. Encapsulation of baby hamster kidney (BHK) cells in alginate microcapsules was performed using a simple device consisting of a cylinder of compressed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Alginate; Beads controlled release drug delivery microcapsules.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000100023

Procédé d'extrusion réactive et/ou enzymatique pour l'extraction de phycocolloïdes : application aux produits de la mer
Provedor de dados: 5
Autores: Makoure, Dounia; Arhaliass, Abdellah; Echchelh, Adil; Baron, Regis; Legrand, Jack.
In this paper we present the reactive extrusion process to extract the phycocolloids from the sea products. By comparing with other techniques, this process has a several advantages like the economic return, the flexibility, the production of various products with different characteristics and time gains. There are two types of extruder: single-screw and double-screw, each one has its specific properties. The solid products are introduced by means of the hopper that is equipped with a dosage pump for the regulation of the flow. Liquid products are, generally, injected in the not filled zones, through an external pump. The products undergo thermo mechanical modifications and then the shaping of the final products was done in the die. The reactive extrusion...
Tipo: Text
Palavras-chave: Extrusion réactive; Valorisation; Coproduits; Produits de la mer; Phycocolloïdes alginate; Reactive extrusion; Valorization; By-products; Sea-products; Phycocolloids; Alginate.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00500/61171/64645.pdf

Evolutionary Evidence of Algal Polysaccharide Degradation Acquisition by Pseudoalteromonas carrageenovora 9(T) to Adapt to Macroalgal Niches
Provedor de dados: 5
Autores: Gobet, Angelique; Barbeyron, Tristan; Matard-mann, Maria; Magdelenat, Ghislaine; Vallenet, David; Duchaud, Eric; Michel, Gurvan.
About half of seaweed biomass is composed of polysaccharides. Most of these complex polymers have a marked polyanionic character. For instance, the red algal cell wall is mainly composed of sulfated galactans, agars and carrageenans, while brown algae contain alginate and fucose-containing sulfated polysaccharides (FCSP) as cell wall polysaccharides. Some marine heterotrophic bacteria have developed abilities to grow on such macroalgal polysaccharides. This is the case of Pseudoalteromonas carrageenovora 9(T) (ATCC 43555(T)), a marine gammaproteobacterium isolated in 1955 and which was an early model organism for studying carrageenan catabolism. We present here the genomic analysis of P. carrageenovora. Its genome is composed of two chromosomes and of a...
Tipo: Text
Palavras-chave: Carrageenan; CAZymes; Alginate; Gammaproteobacteria; Pseudoalteromonas; Marine bacteria; Algal holobiont; Biofilm.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00489/60070/63377.pdf

Development of alginate hydrogels active against adhesion of microalgae
Provedor de dados: 5
Autores: Nassif, L. Abi; Rioual, S.; Trepos, Rozenn; Fauchon, M.; Farah, W.; Hellio, C.; Abboud, M.; Lescop, B.
Microorganisms have the ability to settle on nearly all man-made surfaces in contact with seawater and subsequently to form biofilm. Biofilms control and removal is necessary in the sectors of maritime transport, energy... In this work, we present the development of new pure calcium, zinc or copper alginate, but also mixed Ca/Cu and Ca/Zn alginate hydrogels. These materials have been evaluated for their potential inhibition of adhesion of two key biofilm-forming microalgae Halamphora coffeaeformis and Cylindrotheca closterium). All the tested materials have presented high adhesion inhibition about 80%). Copper-base materials present a high toxicity against H. coffeaeformis. Pure zinc alginate is also toxic for this strain. However, the addition of calcium...
Tipo: Text
Palavras-chave: Biofilm; Adhesion; Alginate; Zinc; Biomaterials; Microalgae.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00605/71671/70168.pdf

Reduction of potential ennoblement of stainless steel in natural seawater by an ecofriendly biopolymer
Provedor de dados: 5
Autores: Abi Nassif, L.; Rioual, S.; Farah, W.; Hellio, C.; Fauchon, M.; Trepos, R; Abboud, M.; Diler, E.; Thierry, D.; Lescop, B.
The effect of biofilm formation on passive stainless steel in seawater environments is of primary importance since it leads to potential ennoblement of surfaces and subsequently to localized corrosion such as pitting and crevice corrosion. This study aims at developing an ecofriendly alginate biopolymer containing both non-toxic calcium and a limited amount of biocidal zinc ions which inhibits this effect. For this purpose, calcium alginate containing less than 1 % of zinc ions localized in the vicinity of the steel surface in natural and renewed seawater is demonstrated to reduce significantly the ennoblement process of steel. After 1 month of immersion, a mass loss of only 4 % of the active material is observed authorizing thereby long-term protection of...
Tipo: Text
Palavras-chave: Biopolymer; Steel; Ennoblement; Antimicrobial; Alginate; Biofilm.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00604/71607/73083.pdf

Nouvelles perspectives dans l'exploitation des laminaires
Provedor de dados: 5
Autores: Braud, Jean-paul; Debroise, Reginald; Perez, René.
Tipo: Text
Palavras-chave: Alginate; Demineralization; Exploitation; Seaweed; Laminaria.
Ano: 1977
URL: http://archimer.ifremer.fr/doc/1977/publication-1967.pdf

Dynamical modelling of a reactive extrusion process: Focus on residence time distribution in a fully intermeshing co-rotating twin-screw extruder and application to an alginate extraction process
Provedor de dados: 5
Autores: Baron, Regis; Vauchel, Peggy; Kaas, Raymond; Arhaliass, Abdellah; Legrand, Jack.
The context of this study is the modelling of reactive extrusion process based on an alginate extraction protocol. Residence Time Distribution (RTD) is one important part to predict the kinetics of reactive compounds. A simple model is proposed to predict RTD in fully intermeshing co-rotating twin-screw extruders without reaction. This model, which can be easily extended to reactive case in a future work, is based on the extension of an axial dispersion model, including control parameters (screw speed and flow rate) and geometrical parameters (screw profile and die design). Simulations were performed for various operating and geometrical conditions so as to illustrate possibilities offered by the proposed model. Validation was conducted for two different...
Tipo: Text
Palavras-chave: Alginate; Extraction; Extrusion; Mathematical modelling; Residence time distribution; Simulation; Laminaria digitata.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00005/11592/8985.pdf

Optimisation de procédés innovants pour l'obtention de phycocolloïdes
Provedor de dados: 5
Autores: Vauchel, Peggy.
Alginates are polysaccharides which are naturally present in the cell wall of brown algae and extracted because of their rheological properties. The alginate industry uses an extraction protocol, which central step, the carbonatation, is conducted in batch reactors. It is a high water, reagent and time demanding process. The main objective of this thesis is to optimize the alginate extraction process. A study of the existing process, focused on carbonatation step, enabled to highlight points which could be enhanced to optimize the extraction yield and the quality of extracted alginates. Stirring intensity and algae pieces size have been identified as parameters having an influence on the carbonatation reaction kinetics. A specific analysis on medullar and...
Tipo: Text
Palavras-chave: Alginate; Extraction; Laminaria digitata; Extrusion réactive; Optimisation; Modélisation; Distribution des temps de séjour; Cinétique; Rendement; Propriétés rhéologiques; Alginate; Extraction; Laminaria digitata; Reactive extrusion; Optimization; Modeling; Residence time distribution; Kinetics; Extraction yield; Rheological properties.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00002/11364/7937.pdf

Kinetics modeling of alginate alkaline extraction from Laminaria digitata
Provedor de dados: 5
Autores: Vauchel, Peggy; Le Roux, Karine; Kaas, Raymond; Arhaliass, Abdellah; Baron, Regis; Legrand, Jack.
Alginates being depolymerized during their alkaline extraction, reducing extraction time could help producing higher rheological quality alginates. The purpose of the present work is to study fresh Laminaria digitata destructuration during alkaline extraction and its link to extraction kinetics. Both alginate extraction yield and mean diameter of algae particles were followed for different values of agitation level and initial size of algae pieces. Results highlighted the existence of a link between extraction yield and algal destructuration. Those elements and the specificity of L. digitata structure have been taken into account to propose a kinetics model based on a fluid-particle reaction with decreasing size particles. The model parameters have been...
Tipo: Text
Palavras-chave: Model; Laminaria digitata; Alkaline extraction kinetics; Alginate.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6315.pdf

A New Process for Extracting Alginates from Laminaria digitata: Reactive Extrusion
Provedor de dados: 5
Autores: Vauchel, Peggy; Kaas, Raymond; Arhaliass, Abdellah; Baron, Regis; Legrand, Julien.
Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The main step in the extraction protocol used in the alginate industry is that of alkaline extraction. A batch process is used for this step, which is time-, water-, and reactant-consuming. The possibility of extracting by reactive extrusion was investigated. The reactive extrusion process appeared to be more efficient than the batch process for the alkaline extraction of alginates from Laminaria digitata in several key ways: Time demand is reduced from about an hour to only few minutes, water and reactant requirements are divided by more than a factor 2, extraction yield is 15% higher (relative enhancement), and the rheological...
Tipo: Text
Palavras-chave: Intrinsic viscosity; Reactive extrusion; Laminaria digitata; Alkaline extraction; Alginate.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-6255.pdf

Decrease in dynamic viscosity and average molecular weight of alginate from Laminaria digitata during alkaline extraction
Provedor de dados: 5
Autores: Vauchel, Peggy; Arhaliass, Abdellah; Legrand, Jack; Kaas, Raymond; Baron, Regis.
Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1-4 h in duration were determined, indicating depolymerization of alginates: average molecular weight decreased significantly during the extraction, falling by a factor of 5 between 1 and 4 h of extraction. These results suggested that reducing extraction time could enable preserving the rheological...
Tipo: Text
Palavras-chave: Laminaria digitata; Intrinsic viscosity; Depolymerization; Average molecular weight; Alkaline extraction; Alginate.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4060.pdf

Soy Protein Isolate-Alginate Microspheres for Encapsulation ofEnterococcus faecalis HZNU P2
Provedor de dados: 52
Autores: Zhang,Yu; Zheng,Wei; Gu,Jian-Fei; Ni,Jian; Wang,Ling; Tang,Zhen-Xing; Shi,Lu-E.
ABSTRACTIn this work, the mixture of alginate and soy protein isolate used as a wall material was developed to encapsulateEnterococcus faecalis HZNU P2 (E. faecalis HZNU P2). The survival ability in the simulated gastric fluid (SGF) and bile salt solution, storage stability at different temperatures and release properties in the simulated intestinal fluid (SIF) of encapsulated cells were assessed. The results showed that encapsulation could offer sufficient protection toE. faecalis HZNU P2. The viability of encapsulatedE. faecalis HZNU P2 did not decrease in SGF at pH 2.5 or 2.0 after 2 h incubation, while free cells were reduced from 11 to 9.85 log CFU/mL in SGF (pH 2.5) at the same exposure time. Only minor viability of encapsulatedE. faecalis HZNU P2...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Enterococcus faecalis; Encapsulation; Soy protein isolate; Alginate; Stability; Viability.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132015000500805

Activity of encapsulated Lactobacillus bulgaricus in alginate-whey protein microspheres
Provedor de dados: 52
Autores: Chen,Meng-Yan; Zheng,Wei; Dong,Qiu-Yue; Li,Zhen-Hua; Shi,Lu-E; Tang,Zhen-Xing.
In this work, alginate-whey protein was used as wall materials for encapsulating Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus). The characteristics of encapsulated and free L. bulgaricus showed that the free L. bulgaricus lost viability after 1 min exposure to simulated gastric fluid (SGF) at pH 2.0 and 2.5. However, the viability of encapsulated L. bulgaricus did not decrease in SGF at pH 2.5 for 2 h incubation. The viable numbers of encapsulated L. bulgaricus decreased less than 1.0 log unit for 2 h incubation in SGF at pH 2.0. For bile stability, only 1.2 log units and 2.0 log units viability of the encapsulated L. bulgaricus was lost in 1 and 2% bile for 1 h exposure, respectively, compared with no survival of free L. bulgaricus under the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Encapsulation; Alginate; Whey protein; Probiotics; Stability.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132014000500736

Effect of Nutrient Sources on the Alginate Accumulation in the Culture Liquid of Azotobacter vinelandii D-05 and Obtaining Biocomposite Materials
Provedor de dados: 52
Autores: Revin,Victor Vasilevich; Kostina,Elena Gennadievna; Revina,Nadezhda Victorovna; Shutova,Vitalina Victorovna.
ABSTRACT Using the classic biotechnological methods, the dependence of A. vinelandii D-05 culture alginate production from the media carbon and nitrogen content was investigated. The maximal alginate production was observed during cultivation bacterium in the medium with 2 to 4% of sucrose, but the maximal growth was found in the medium with 4% glucose. It was found that for the alginate production the optimal nitrogen contents could take from 0.05% yeast extract (carbon: nitrogen ratio 168:1). For the first time we demonstrated possibility the A. vinelandii growth during the cultivation in a medium with molasses (a by-product of sugar production) and the significant polysaccharide production (16.6 g/l) was obtained. It was established, that A. vinelandii...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Azotobacter vinelandii; Alginate; Nutrient medium; Carbon: nitrogen ratio; Biocomposite.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132018000100407

Stability of free and immobilized Lactobacillus acidophilus and Bifidobacterium lactis in acidified milk and of immobilized B. lactis in yoghurt
Provedor de dados: 58
Autores: Grosso,Carlos Raimundo Ferreira; Fávaro-Trindade,Carmen Sílvia.
This study evaluated the stability of Bifidobacterium lactis (Bb-12) and of Lactobacillus acidophilus (La-05) both free and immobilized in calcium alginate, in milk and in acidified milk (pH 5.0, 4.4 and 3.8). The stability of immobilized B. lactis in yoghurt (fermented to pH 4.2), during 28 days of refrigerated storage was also evaluated. The efficiency of two culture media (modified MRS agar and Reinforced Clostridial Agar plus Prussian Blue) for counting of B. lactis in yoghurt was determined. Lee's agar was used to count Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus when B. lactis were counted in the MRS medium. B. lactis and L. acidophilus in both free and immobilized forms presented satisfactory rates of survival in milk...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Probiotics; Immobilization; Alginate; Lactobacillus acidophilus; Bifidobacterium lactis; Yoghurt; Milk; Lactobacillus bulgaricus.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822004000100025

Continuous ethanol production using immobilized yeast cells entrapped in loofa-reinforced alginate carriers
Provedor de dados: 58
Autores: Bangrak,Phoowit; Limtong,Savitree; Phisalaphong,Muenduen.
A culture of Saccharomyces cerevisiae M30 entrapped in loofa-reinforced alginate was used for continuous ethanol fermentation in a packed-bed reactor with initial sugar concentrations of 200-248 g/L. Maximum ethanol productivity of 11.5 g/(L·h) was obtained at an ethanol concentration of 57.4 g/L, an initial sugar concentration of 220 g/L and a dilution rate (D) of 0.2 h-1. However, a maximum ethanol concentration of 82.1 g/L (productivity of 9.0 g/(L·h)) was obtained at a D of 0.11 h-1. Ethanol productivity in the continuous culture was 6-8-fold higher than that in the batch culture. Due to the developed carrier's high biocompatibility, high porosity, and good mechanical strength, advantages such as cell regeneration, reusability, altered mechanical...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ethanol; Loofa; Alginate; Immobilization; Continuous.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822011000200032

Preparation and characterization of microcapsules of Pterodon pubescens Benth. by using natural polymers
Provedor de dados: 60
Autores: Reinas,Alexandre Espada; Hoscheid,Jaqueline; Outuki,Priscila Miyuki; Cardoso,Mara Lane Carvalho.
An oleaginous fraction obtained from an alcohol extract of the fruit of Pterodon pubescensBenth. (FHPp) was microencapsulated in polymeric systems. These systems were developed using a complex coacervation method and consisted of alginate/medium-molecular-weight chitosan (F1-MC), alginate/chitosan with greater than 75% deacetylation (F2-MC), and alginate/low-molecular-weight chitosan (F3-MC). These developed systems have the potential to both mask the taste of the extract, and to protect its constituents against possible chemical degradation. The influence of the formulation parameters and process were determined by chemical profiling and measurement of the microencapsulation efficiency of the oleaginous fraction, and by assessment of microcapsule...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pterodon pubescensBenth./pharmacognosy; Sucupira; Microcapsules/preparation; Vouacapans; Alginate; Chitosan; Coacervation method; Natural polymers; Natural products.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502014000400919

Controlled release alginate-chitosan microspheres of tolmetin sodium prepared by internal gelation technique and characterized by response surface modeling
Provedor de dados: 60
Autores: Elsayed,Mahmoud M. A.
Tolmetin sodium (TS) is a powerful non-steroidal mitigating drug for the treatment of rheumatoid joint inflammation, osteoarthritis, and adolescent rheumatoid joint pain. In addition to its gastrointestinal (GIT) problems, TS has a short biological half-life (1 hr). In a trial to overcome these side effects and control the rate of (TS) release, chitosan coated alginate microspheres are recommended. A Box-Behnken experimental design was employed to produce controlled release microspheres of TS in the sodium alginate and chitosan copolymers (Alg-Ch) by emulsification internal gelation methodology. The effect of critical formulation variables namely, drug to polymer ratio (D:P ratio), speed of rotation and span 80% on drug encapsulation efficiency (% EE),...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Tolmetin Sodium; Controlled Release; Alginate; Chitosan; Response Surface.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502020000100604

Microencapsulation of probiotics using sodium alginate
Provedor de dados: 65
Autores: Etchepare,Mariana de Araújo; Barin,Juliano Smanioto; Cichoski,Alexandre José; Jacob-Lopes,Eduardo; Wagner,Roger; Fries,Leadir Lucy Martins; Menezes,Cristiano Ragagnin de.
The consumption of probiotics is constantly growing due to the numerous benefits conferred on the health of consumers. In this context, Microencapsulation is a technology that favors the viability of probiotic cultures in food products, mainly by the properties of protection against adverse environmental conditions and controlled release. Currently there are different procedures for microencapsulation using polymers of various types of natural and synthetic origin. The use of sodium alginate polymers is one of the largest potential application in the encapsulation of probiotics because of their versatility, biocompatibility and toxicity exemption. The aim of this review is to present viable encapsulation techniques of probiotics with alginate, emphasizing...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Alginate; Controlled release; Microencapsulation; Probiotics.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015000701319

Production and characterization of alginate microparticles obtained by ionic gelation and electrostatic adsorption of concentrated soy protein
Provedor de dados: 65
Autores: Silverio,Gabriela Barros; Sakanaka,Lyssa Setsuko; Alvim,Izabela Dutra; Shirai,Marianne Ayumi; Grosso,Carlos Raimundo Ferreira.
ABSTRACT:  Microencapsulation is used for protection and release of bioactive compounds. Combination of encapsulation methods allows the production of matrices with better technological properties compared to the application of one of the methods alone. Use of ionic gelation produces porous microparticles, and coating it with a protein, by electrostatic interaction, may contribute to a better protection of the active compound. The objective of the research was to produce alginate microparticles (AG) through ionic gelation and to coat them with soluble protein from soy protein concentrate. Two factors were studied, calcium concentration during ionic gelation (0.8, 1.6 and 2.4% w/w) and pH (3.5 and 7.0) of the protein solution for electrostatic interaction....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Microencapsulation; Ionic gelation; Electrostatic interaction; Alginate; Soy protein.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018001200750