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	Provedor de dados ArchiMer (3) Autor Petit, Anne-celine (3) Colliec-jouault, Sylvia (2) Guezennec, Jean (2) Gondrexon, N (1) Noiret, N (1) Noiret, Nicolas (1) Ratiskol, Jacqueline (1) Sinquin, Corinne (1) Mais... Palavra-chave Depolymerization (2) Exopolysaccharide (2) Bacterial exopolysaccharide (1) Catalyse métallique (1) Deep sea hydrothermal (1) Dépolymérisation (1) Esterification (1) Estérification (1) Free radical depolymerization (1) H202 (1) Metal (1) Metallic catalysts (1) Oxidation (1) Oxydation (1) Sonochemistry (1) Source hydrothermale (1) Sulfatation (1) Sulfation (1) Ultrasons (1) Ultrasound (1) Mais... Tipo do documento Text (3) Ano 2007 (1) 2006 (1) 2005 (1) País France (3) Idioma Inglês (2) Francês (1)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 3 Primeira ... 1 ... Última Free-radical depolymerization with metallic catalysts of an exopolysaccharide produced by a bacterium isolated from a deep-sea hydrothermal vent polychaete annelid ArchiMer Petit, Anne-celine; Noiret, N; Sinquin, Corinne; Ratiskol, Jacqueline; Guezennec, Jean; Colliec-jouault, Sylvia. Free-radical depolymerization with metallic catalysts has been investigated to depolymerize an exopolysaccharide (EPS), with a high molecular weight (> 10(6) g/Mol), produced by the bacterium Alteromonas macleodii subsp. fijiensis biovar deepsane. Three metals (copper, zinc and manganese) were used either alone or mixed. These metals led to the depolymerization of the high molecular weight bacterial polysaccharide with different efficiency. This study specifies some conditions required to produce, with good reproducibility and yield, EPS derivatives of reduced molecular weight ranging from 100,000 to 20,000 g/mol. The more influential parameters are specified. This is a first study to find suitable industrial conditions in the presence of these metallic... Tipo: Text Palavras-chave: Bacterial exopolysaccharide; Free radical depolymerization; H202; Metal. Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-2146.pdf Modifications d'un exopolysaccharide biosynthétisé par une bactérie issue des écosystèmes Hydrothermaux profonds ArchiMer Petit, Anne-celine. Le travail présenté dans ce mémoire concerne la modification d'un exopolysaccharide (EPS), l'HYD 657, biosynthétisé par une bactérie issue des écosystèmes hydrothermaux profonds. Ce polysaccharide d'un poids moléculaire de 1,8.106 Da est composé de 40-50% d'oses neutres et de 30- 40% d'acides uroniques. L'hypothèse de structure la plus probable décrit son unité de répétition comme un undécasaccharide possédant 3 ramifications courtes. Cet EPS, sous sa forme native, a déjà fait l'objet d'une étude approfondie en vue d'applications dans le domaine de la cosmétique pour ses propriétés apaisantes en application topique cutanée. Pour élargir le spectre d'applications de cet EPS, la réduction de sa masse molaire a été envisagée. La première partie décrit la... Tipo: Text Palavras-chave: Oxidation; Sulfation; Esterification; Metallic catalysts; Sonochemistry; Deep sea hydrothermal; Depolymerization; Exopolysaccharide; Oxydation; Sulfatation; Estérification; Catalyse métallique; Ultrasons; Source hydrothermale; Dépolymérisation; Exopolysaccharide. Ano: 2005 URL: http://archimer.ifremer.fr/doc/2005/these-1232.pdf Ultrasonic depolymerization of an exopolysaccharide produced by a bacterium isolated from a deep-sea hydrothermal vent polychaete annelid ArchiMer Petit, Anne-celine; Noiret, Nicolas; Guezennec, Jean; Gondrexon, N; Colliec-jouault, Sylvia. Low frequency ultrasound was used to depolymerize a high-molecular-weight exopolysaccharide (EPS) produced by a deep-sea hydrothermal bacterium Alteromonas macleodii subsp. fijiensis biovar deepsane. The influence of several parameters was examined including the duration of ultrasonic irradiation, EPS concentration. reaction temperature and volume of the sonicated solution. With the aim of optimizing the depolyrnerization, the native EPS was simultaneously treated with hydrogen peroxide and ultrasound. This study identified the sonication conditions that produce low-molecular-weight derivatives from the native EPS (>10(6) Da) with good reproducibility. (C) 2006 Elsevier B.V. All rights reserved. Tipo: Text Palavras-chave: Exopolysaccharide; Depolymerization; Ultrasound. Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-2123.pdf Registros recuperados: 3 Primeira ... 1 ... Última

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