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Modification des Propriétés Physico-Chimiques des Carraghénanes par la Purification et Caractérisation de Carraghénane-Sulfatases

Abstract : Carrageenans are sulfated galactans extracted from cell wall of numerous species of red seaweeds. These polysaccharides of marine origin present unique rheological properties, and are widely used as texturing agents in the food, cosmetic, and pharmaceutical industries. They are composed of galactose units linked alternatively by alpha (1→3) and beta (1→4) links, and differ by the occurence of 3,6-anhydro bridge and their degree of sulfatation. However, carrageenans are heteropolymers and present complex hybrid stuctures in nature. The variability of carrageenan composition, which depends on algal species, life stage and extraction processes, offers a wide range of physico-chemical properties for various applications. In order to master the rheological properties of carrageenans, it’s necessary to control their chemical structures. To this end, the purification of enzymes of desulfatation -called sulfatases- was undertaken allowing monitoring directly on the gelling properties of these polysaccharides. These enzymes catalyse the hydrolysis of sulfate esters bonds of many biological compounds, and are involved in many metabolic processes. Through a screening, several carrageenan-sulfatases have been highlighted in the marine bacterium P. atlantica. Purification of two of them (Q15XH3, Q15XH1) showed that they were fomylglycine-dependent sulfatases, and led to the identification of a cluster of genes involved in the biodegradation of carrageenans. Overexpression of others sulfatases from this cluster has allowed characterizing a new carrageenan-sulfatase (Q15XG7). Studies conducted without a priori in the bacterium P. atlantica has also revealed the existence of two carrageenases. Sulfatases studied has allowed preparing of new carrageenans, including the production of pure Alpha-carrageenan. These results open new perspectives of biotechnological applications in carrageenan industry.
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https://tel.archives-ouvertes.fr/tel-01301274
Contributor : Aurélie Prechoux <>
Submitted on : Tuesday, April 12, 2016 - 9:57:37 PM
Last modification on : Friday, May 24, 2019 - 4:59:42 PM
Document(s) archivé(s) le : Wednesday, July 13, 2016 - 10:31:07 AM

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  • HAL Id : tel-01301274, version 1

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Préchoux Aurélie. Modification des Propriétés Physico-Chimiques des Carraghénanes par la Purification et Caractérisation de Carraghénane-Sulfatases. Sciences du Vivant [q-bio]. Université Pierre et Marie Curie - UPMC, 2012. Français. ⟨tel-01301274⟩

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