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Covis R.,National Graduate School of Chemistry, Rennes | Covis R.,European University of Brittany | Vives T.,National Graduate School of Chemistry, Rennes | Vives T.,European University of Brittany | And 5 more authors.
Carbohydrate Polymers | Year: 2015

The interaction between anionic algal polysaccharides ((κ)-, (ι)-, (λ)-carrageenans, alginate and ulvan) and a cationic glycine betaine (GB) amide surfactant possessing a C18:1 alkyl chain has been studied using isothermal titration calorimetry (ITC), zeta-potential measurements, dynamic light scattering (DLS), transmission electron microscopy (TEM), atomic force microscopy (AFM), and surface tension measurements. It was observed that this cationic surfactant derived from renewable raw materials induced cooperative binding with the anionic polymers at critical aggregation concentration (CAC) and the CAC values are significantly lower than the corresponding critical micelle concentration (CMC) for the surfactant. The CMC of cationic GB surfactant was obtained at higher surfactant concentration in polysaccharide solution than in pure water. More interestingly, the presence of original polysaccharide/surfactant hybrid complexes formed above the CMC value was evidenced from (κ)-carrageenan by microscopy (TEM and AFM). Preliminary investigations of the structure of these complexes revealed the existence of surfactant nanoparticles surrounded with polysaccharide matrix, probably resulting from electrostatic attraction. In addition, ITC measurements clearly showed that the interactions of the κ-carrageenan was stronger than for other polysaccharides ((ι)-, (λ)-carrageenans, alginate and ulvan). These results may have important impact on the use of the GB amide surfactant in formulations based on algal polysaccharides for several applications such as in food, cosmetics, and detergency fields © 2015 Elsevier Ltd. All rights reserved. Source

Jard G.,French National Institute for Agricultural Research | Marfaing H.,Center Detude Et Of Valorisation Des Algues | Carrere H.,French National Institute for Agricultural Research | Delgenes J.P.,French National Institute for Agricultural Research | And 2 more authors.
Bioresource Technology | Year: 2013

Macroalgae are biomass resources that represent a valuable feedstock to be used entirely for human consumption or for food additives after some extractions (mainly colloids) and/or for energy production. In order to better develop the algal sector, it is important to determine the capacity of macroalgae to produce these added-values molecules for food and/or for energy industries on the basis of their biochemical characteristics. In this study, ten macroalgae obtained from French Brittany coasts (France) were selected. The global biochemical composition (proteins, lipids, carbohydrates, fibers), the presence and characteristics of added-values molecules (alginates, polyphenols) and the biochemical methane potential of these algae were determined. Regarding its biochemical composition, Palmaria palmata is interesting for food (rich in nutrients) and for anaerobic digestion (0.279LCH4/gVS). Saccharina latissima could be used for alginate extraction (242g/kgTS, ratio between mannuronic and guluronic acid M/G=1.4) and Sargassum muticum for polyphenol extraction (19.8g/kgTS). © 2013 Elsevier Ltd. Source

Covis R.,National Graduate School of Chemistry, Rennes | Covis R.,European University of Brittany | Guegan J.-P.,National Graduate School of Chemistry, Rennes | Guegan J.-P.,European University of Brittany | And 5 more authors.
Journal of Polymer Research | Year: 2016

Cationized kappa-carrageenans containing 2-hydroxy-3-(trimethylammonium)propyl groups with various degrees of substitution (0.13–0.75) were synthesized by reaction of sulfated polysaccharides with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (QUAB 188) in alkaline solutions through the generation of the corresponding 2,3-epoxy reagent in situ. The structure of the modified algal polysaccharides was characterized without any further treatment or after methanolysis and/or enzymatic depolymerization, by means of spectroscopic tools (FT-IR, NMR, Mass spectrometry) and high-performance size exclusion chromatography (HPSEC). Significant differences in the rheological properties of these cationized kappa-carrageenans have been found depending on the DS values and the presence of KCl salt. Despite their lower molecular weights in comparison with native polysaccharides, cationized kappa-carrageenans with a DS of 0.75 exhibited high viscosity and gelling behaviors mediated by the high density of quaternary ammonium groups. © 2016, Springer Science+Business Media Dordrecht. Source

Peu P.,IRSTEA | Peu P.,European University of Brittany | Sassi J.-F.,Center Detude Et Of Valorisation Des Algues | Girault R.,IRSTEA | And 9 more authors.
Bioresource Technology | Year: 2011

Seaweed (Ulva sp.) stranded on beaches were utilized as co-substrate for anaerobic digestion of pig slurry in three-month co-digestion tests in pilot scale anaerobic digesters in the laboratory. The methanogenic potential of Ulva sp. was low compared to that of other potential co-substrates available for use by farmers: 148Nm 3CH 4/t of volatile solids or 19Nm 3CH 4/t of crude product. When used as a co-substrate with pig manure (48%/52% w/w), Ulva sp. seaweed did not notably disrupt the process of digestion; however, after pilot stabilisation, biogas produced contained 3.5% H 2S, making it unsuitable for energy recovery without treatment. Sequentially addition of the sulphate reduction inhibitor, potassium molybdate, to a final concentration of 3mM, temporarily reduced H 2S emissions, but was unable to sustain this reduction over the three-month period. According to these pilot tests, the use of seaweed stranded on beaches as co-substrate in farm-based biogas plants shows some limitations. © 2011 Elsevier Ltd. Source

Taelman S.E.,Ghent University | Champenois J.,Center Detude Et Of Valorisation Des Algues | Edwards M.D.,National University of Ireland | De Meester S.,Ghent University | And 2 more authors.
Algal Research | Year: 2015

Environmental concerns regarding natural resource depletion have led to the cultivation of more renewable resources such as seaweed biomass. As the cultivation in Europe is still in its early stages, an estimation of the environmental sustainability may boost further development of this sector by highlighting its competitiveness. A case study on the resource footprint of Saccharina latissima production near the West coast of Ireland (18ha of floating longlines) and France (0.6ha of raft systems) is performed. The Cumulative Exergy Extraction from the Natural Environment (CEENE) method is used to quantify the exergy deprived from 8 types of natural resources (incl. marine resources) to produce 1MJex biomass. For Ireland and France, results of the Exergetic Life Cycle Assessment (ELCA) are 1.7MJexMJex -1 and 8.7MJexMJex -1, respectively. Compared to the footprint of microalgae and several terrestrial plants (sugar beets, maize and potatoes), typically showing values in the range of 0.92-3.88MJexMJex -1, seaweed production in North West Europe (especially in Ireland) is relatively resource-efficient. Moreover, the potential to improve the resource footprint of seaweed production is investigated; in the short-term, seaweed can be cultivated with a comparable life cycle resource demand as several land plants. © 2015 Elsevier B.V. Source

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