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Knoerr R.,CNRS Mulhouse Institute of Materials Science | Brendle J.,CNRS Mulhouse Institute of Materials Science | Lebeau B.,CNRS Mulhouse Institute of Materials Science | Demais H.,OLMIX SA
New Journal of Chemistry | Year: 2011

A new kind of composite material made of diatomite and deviline (CaCu 4(SO4)2OH6·3H2O) has been prepared by mixing diatomite and aqueous solutions of copper(ii) sulfate at room temperature for 8 h. X-Ray powder diffraction shows evidence for the contribution of calcium carbonate initially present in the diatomite in the formation of deviline. The formation of deviline onto diatomite surface, as observed by EDX and SEM analysis, is suggested to occur by the formation of hydrogen bonds between the surface silanol groups and cupric species. Two mechanisms of formation of deviline are suggested. Remediation properties of diatom-Cu towards Pb(ii) cations in aqueous solution were investigated. The materials have a noticeably higher Pb(ii) sorption capacity (130 mg g -1) than the native diatomite (25 mg g-1). Such a performance is attributed to the mechanism of Pb(ii) immobilization, characterized by the precipitation of the stable caledonite phase (Cu 2Pb5(SO4)3(OH)6CO 3) from the dissolution of deviline. © 2011 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. Source


Hardouin K.,University of Southern Brittany | Hardouin K.,OLMIX SA | Bedoux G.,University of Southern Brittany | Burlot A.-S.,University of Southern Brittany | And 2 more authors.
Advances in Botanical Research | Year: 2014

Seaweeds are the basis of a multibillion-dollar economy with an impact on highly diverse sectors, including food, feed, textile, pharmaceutical, nutraceutical, cosmetic, chemistry, bioactive compounds, and biotechnological sectors like bioenergy. Molecules from seaweed have provided promising drug leads, offered new targets for synthetic chemists, and provided opportunities for the elucidation of unusual biosynthetic pathways. Seaweed farming has developed all over the world. Simultaneously, the increasing report of outbreaks of 'green tides' ('brown or red tides'), fouling species and large piles of decomposing biomass which appear along shallow sandy bays represent a true economic constraint for the affected communities. Harvesting of invasive and proliferative species is an opportunity for collecting an important biomass for research of new compounds of interest. This review describes enzymatic processing of seaweeds as reported for the last 20. years. At this time when sustainable development and environmental protection are regarded as key factors, studies about innovative extraction processes of active compounds from natural products have attracted special attention. The use of enzyme treatment as a tool to improve the extraction efficiency of bioactive compounds from seaweeds shows several benefits. This chapter presents a synthesis of the conditions applied for seaweed cracking. Three different types of hydrolysis are used depending on the process design and the nature of the enzymes. Biochemical composition of hydrolysates, enzymatic hydrolysis efficiency, and biological activities depend on the nature of the macroalgae, the enzyme activity, the experimental conditions and the design process. Among the biological properties, the hydrolysates show various activities: antioxidant, antiviral, antiproliferative, antihypertensive and anticoagulative. These data demonstrate some potential applications of seaweed metabolites obtained by enzymatic hydrolysis and of the prospects for the future. © 2014 Elsevier Ltd. Source


Hardouin K.,University of Southern Brittany | Hardouin K.,OLMIX SA | Bedoux G.,University of Southern Brittany | Burlot A.-S.,University of Southern Brittany | And 4 more authors.
Algal Research | Year: 2016

In order to develop innovative methods for the production of bioactive extracts with potential health benefits, enzyme-assisted extraction has been applied for the bioconversion of Ulva armoricana (Ulvales, Ulvophyceae). The extraction yields, chemical composition, the antioxidant and antiviral activities were determined to assess the efficiency of six commercial enzymatic preparations. Endo-protease treatments significantly increased the extraction yields compared to the control. The organic matter, neutral sugar and protein contents were increased in all extracts compared to an extraction with water, up to 2.0-fold, 2.7-fold and 1.75-fold, respectively. The samples prepared by a multiple-mix of glycosyl-hydrolases and an exo-β-1,3(4)-glucanase revealed activities against herpes simplex virus type-1 at the median effective concentration (EC50) of 373.0 ± 20.7 and 320.9 ± 33.6 μg/ml, respectively. These activities were correlated to high amounts of rhamnose, uronic acids and sulfate groups which are the main constituents of ulvans. Free radical scavenging capacity at medium inhibition concentrations (IC50) of 1.8 and 12.5 mg/ml was shown for the extracts produced with endo-protease treatments and 6.0 mg/ml for the sample resulting from the extraction with the multiple-mix of glycosyl-hydrolases. This study reports the antiviral and antioxidant activities of Ulva armoricana extracts produced by enzyme-assisted extraction. © 2016 Elsevier B.V. Source


Knoerr R.,CNRS Mulhouse Institute of Materials Science | Brendle J.,CNRS Mulhouse Institute of Materials Science | Lebeau B.,CNRS Mulhouse Institute of Materials Science | Demais H.,OLMIX SA
Microporous and Mesoporous Materials | Year: 2012

A new iron oxide-diatomite system was synthesized in one pot by mixing natural diatomite with a ferrous sulfate solution at room temperature. The characterization of the materials (Diatom-Fe) by XRD and chemical analysis revealed that iron (29%. w/w) was crystallized under goethite phase (α-FeOOH). Analysis conducted by SEM further highlighted the preferential presence of goethite on the surface of diatomite, which involves hydrogen bonding between diatomite surface silanol groups and ion species. The mechanism of formation of goethite is suggested to occur through the precipitation of ferrous ions by hydroxyls ions followed by the oxidation of the iron species to yield first to lepidocrocite (γ-FeOOH) then goethite that is thermodynamically more stable. Within this mechanism, the contribution of calcium carbonate through its dissolution into hydroxyls species is evidenced by XRD and FTIR analyses. The remediation properties of Diatom-Fe towards arsenite species cations were investigated in batch jar tests for 24. h at auto-equilibrium pH. The materials showed a noticeable higher As (III) sorption capacity (16. mg/g) than the native diatomite (0.5. mg/g). These results can be explained by the strong affinity of arsenites to goethite which is further emphasized by the dispersion of the iron oxide crystals on diatomite surface. © 2012 Elsevier Inc. Source


Bedoux G.,University of Southern Brittany | Hardouin K.,University of Southern Brittany | Hardouin K.,OLMIX SA | Burlot A.S.,University of Southern Brittany | Bourgougnon N.,University of Southern Brittany
Advances in Botanical Research | Year: 2014

Marine macroalgae biomass is often used for the production of ingredients in cosmetics. These ingredients can have one of the three main functions: (1) they are considered as additives which contribute to the organoleptic properties; (2) they are used for stabilisation and preservation of the product; (3) or finally, they are bioactive compounds which fulfil a real cosmetic function and activity. This chapter presents the bioactivities of molecules or extracts used for cosmetic applications, and discusses some perspectives for the development of new compounds and specific extraction methods. Metabolites derived from seaweeds have been shown to be active in antiaging skin care, anticellulite treatment and slimming, as well as having antioxidant, photoprotective, moisturising, and whitening properties. Among the various classes of seaweed components, sulphated polysaccharides, peptides, carotenoids, fatty acids, and phytohormones exhibit antiaging and antioxidant properties, while mycosporine-like amino acids, flavonoids have an antiphotoaging activity. Flavonoids (i.e. phlorotannins) are lipolytic agents which are isolated from macroalgae and which also inhibit melanogenesis. A better knowledge of algae genetics and the improvement of algae cultivation or co-cultivation will provide new opportunities for the development of bioactive compounds. © 2014 Elsevier Ltd. Source

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