CNRS Agropolymers Engineering and Emerging Technologies

Montpellier, France

CNRS Agropolymers Engineering and Emerging Technologies

Montpellier, France
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Barakat A.,French National Institute for Agricultural Research | Barakat A.,CNRS Agropolymers Engineering and Emerging Technologies | Gaillard C.,French National Institute for Agricultural Research | Steyer J.-P.,French National Institute for Agricultural Research | Carrere H.,French National Institute for Agricultural Research
Waste and Biomass Valorization | Year: 2014

In order to determine the parameters influencing lignocellulosic biomass biodegradability, binary and ternary model systems were constructed, consisting of cellulose nanowhiskers gel, xylan matrix derived from lignocellulosic plants and synthetic lignin. The adsorption of two xylan polymers with different arabinose/xylose ratios (Ara/Xyl) on the cellulose nanowhiskers resulted in the synthesis of nanocomposites each of different Ara/Xyl ratios and crystallinity indexes. Organized and associated cellulose-xylan-lignin nanocomposites were formed following the polymerization of guäiacyl (G) and syringyl (S) lignin monomers using a peroxidase/H2O2 system in cellulose nanowhiskers-xylan gel. The anaerobic digestion of cellulose nanowhiskers, xylans and cellulose-xylan nanocomposites indicated that the biomethane production depended strongly on the xylan Ara/Xyl ratio and on the cellulose crystallinity. However, the anaerobic digestion of cellulose-xylan-lignin nanocomposites showed that the digestion rate decreased significantly in the presence of lignin. Moreover, there was an even more considerable decrease in digestion rate in the presence of GS-type lignin compared to G-type lignin. © Springer Science+Business Media Dordrecht 2013.


Barakat A.,CNRS Agropolymers Engineering and Emerging Technologies | Monlau F.,CNRS Agropolymers Engineering and Emerging Technologies | Monlau F.,French National Institute for Agricultural Research | Solhy A.,University Mohammed Polytechnique | Carrere H.,French National Institute for Agricultural Research
Applied Energy | Year: 2015

Mechanical size reduction is considered as a primordial step of current and future lignocellulosic biorefinery. In this sense, it is of high interest to understand who are the biochemical and structural features of the lignocellulosic biomass, which affect the Specific Energy Requirement (SER), and in consequence the cost of mechanical size reduction processes. First, it was shown that the initial moisture content of the lignocellulosic biomass affect the SER and the final particle size distribution. The highest the moisture content gives raise the highest SER. Then, at fixed initial moisture content (≈7% DW), structural and biochemical features of lignocellulosic biomass that can affect the SER were determined. It was noticed that both arabinose/xylose ratio and accessible surface area lead to increasing the SER. On the contrary, the content of cellulose, lignin, crystallinity and p-coumaric acids links were found to have a positive effect on the reduction of the SER. © 2015 Elsevier Ltd.


Barakat A.,CNRS Agropolymers Engineering and Emerging Technologies | Mayer-Laigle C.,CNRS Agropolymers Engineering and Emerging Technologies | Solhy A.,University Polytechnique Mohammed | Arancon R.A.D.,University of Cordoba, Spain | And 2 more authors.
RSC Advances | Year: 2014

The transformation of lignocellulosic biomass into biofuels represents an interesting and sustainable alternative to fossil fuel for the near future. However, one still faces some major challenges for the technology to be fully realized including feedstock costs, novel pretreatment processes, production, transportation, and environmental impact of the full chain. The development of new technologies focused to increase the efficiency of cellulose conversion to biofuels determines successful implementation. Mechanical fractionation is an essential step in order to increase final carbohydrate output, appropriate particle sizes and densification, enzymatic accessibility, and bioconversion affectivity without the production of toxic side streams. In this review article, we surveyed a substantial amount of previous work in mechanical fractionation or pretreatments of a variety of lignocellulosic biomasses; these include numerous milling schemes and extrusions, and their impacts on the physical and physicochemical properties of the lignocellulosic matrix (crystallinity, surface area, particle size, etc). We have also compared results with other pure chemical and physicochemical pretreatments in order to show the new aspects and advantages/disadvantages of such an approach. Last, but not least, the effect of mechanical treatment and physical properties on enzymatic hydrolysis and bioconversion has been discussed, with potentially interesting dry lignocellulosic biorefinery schemes proposed. This journal is © the Partner Organisations 2014.


Suriyarak S.,University of Hohenheim | Gibis M.,University of Hohenheim | Schmidt H.,University of Hohenheim | Villeneuve P.,CNRS Agropolymers Engineering and Emerging Technologies | Weiss J.,University of Hohenheim
Journal of Food Protection | Year: 2014

Antimicrobial activity and mechanism of action of rosmarinic acid (RA) and dodecyl rosmarinate (RE12) against Staphylococcus carnosus LTH1502 were studied as a function of pH (5.8 to 7.2) and in the presence of salts (KCl and MgCl 2, 0 to 500 mM). Microbial cultures were exposed to unesterified RA and to esterified RE12, and cell number was determined by plate counting. Cells exposed to RA and RE12 at the minimum bactericidal concentration (200 and 0.05 mM, respectively) were examined using scanning electron microscopy to observe potential morphological changes. Activity of RA was found to be strongly dependent on pH, salt type, and concentration, whereas RE12 led to the compound's activity becoming independent of pH, salt concentration, and type. Scanning electron microscopy images showed that morphology of cells treated with RE12 after incubation of 1 h was irrevocably altered. Our results suggest that esterification (i) altered the mechanism of action by increasing the compound's affinity for cell membranes and (ii) decreased the compound's susceptibility to changes in environmental conditions that alter its charge. Highly specific changes in structure-activity relationships can be observed when esterifying a naturally active phenol such as RA with an alkyl chain that has a carbon chain length of 12. Copyright ©, International Association for Food Protection.


Chuetor S.,CNRS Agropolymers Engineering and Emerging Technologies | Luque R.,University of Cordoba, Spain | Barron C.,CNRS Agropolymers Engineering and Emerging Technologies | Solhy A.,University Mohammed Polytechnique | And 2 more authors.
Green Chemistry | Year: 2015

The separation of lignocellulose into its major components (cellulose, hemicelluloses and lignin) is a key step in lignocellulosic biorefineries. Most pretreatments of lignocellulosic biomass into chemicals or biofuels are currently based on expensive chemical and energy consuming processes, which entail significant resource consumption (e.g. water) and generate a number of residual streams. In this work, two innovative dry fractionation technologies (physical fractionation: turbo- and electrostatic separation of lignocellulose particles) have been developed for rice straw "RS" fractionation and bioconversion to sugars and biofuels. Turbo-fractionation technology (TF-T) comprises particle separation according to their size and density, whereas electrostatic fractionation technology (EF-T) is based on the separation of particles according to their surface properties (chemical composition and charges). TF-T and EF-T are suitable for producing lignocellulose fractions displaying very different structures, biochemical compositions and reactive surfaces without extensively damaging the raw fibers as well as minimizing waste generation (E-factor: 0.7-0.75). The produced fractions could be hydrolyzed, being able to produce large quantities of glucose (250-280 g kg-1 RS) after 72 h of hydrolysis and subsequently ethanol (130-150 g kg-1 RS) after fermentation. TF-T and EF-T can therefore improve the economic feasibility by low energy consumption and produce reactive lignocellulose particles with different physicochemical structures in a short time, which can be easily converted to biofuels, minimizing waste (no effluent generation). This journal is © The Royal Society of Chemistry 2015.


Constant S.,Charles Gerhardt Institute | Barakat A.,CNRS Agropolymers Engineering and Emerging Technologies | Robitzer M.,Charles Gerhardt Institute | Di Renzo F.,Charles Gerhardt Institute | And 2 more authors.
Bioresource Technology | Year: 2016

Cellulosic pulps have been successfully isolated from wheat straw through a Lewis acids organosolv treatment. The use of Lewis acids with different hardness produced pulps with different delignification degrees. The cellulosic residue was characterised by chemical composition, X-ray diffraction, FT-IR spectroscopy, N2 physisorption, scanning electron microscopy and potential for anaerobic digestibility. Surface area and pore volume increased with the hardness of the Lewis acid, in correspondence with the decrease of the amount of lignin and hemicellulose in the pulp. The non linearity of the correlation between porosity and composition suggests that an agglomeration of cellulose fibrils occurs in the early stages of pulping. All organosolv pulps presented a significantly higher methane potential than the parent straw. A methane evolution of 295 N cm3/g OM was reached by a moderate improvement of the accessibility of the native straw. © 2016 Elsevier Ltd


Sambusiti C.,CNRS Agropolymers Engineering and Emerging Technologies | Licari A.,CNRS Agropolymers Engineering and Emerging Technologies | Solhy A.,University Mohammed Polytechnique | Aboulkas A.,Sultan Moulay Slimane University | And 2 more authors.
Bioresource Technology | Year: 2015

The aim of this study was the application of an innovative dry chemo-mechanical pretreatment using different mechanical stresses to produce bioethanol from sugarcane bagasse (SB). The effect of different milling methods on physicochemical composition, enzymatic hydrolysis, bioethanol production and energy efficiency was also evaluated. SB was pretreated with NaOH and H3PO4 at high materials concentration (5kg/L). Results indicate that vibratory milling (VBM) was more effective in the reduction of particles size and cellulose crystallinity compared to centrifugal (CM) and ball (BM) milling. NaOH pretreatment coupling to BM and VBM was preferred to enhance glucose yields and bioethanol production, while CM consumed less energy compared to BM and VBM. Moreover, the highest energy efficiency (η=0.116kgglucose/kWh) was obtained with NaOH-CM. Therefore, the combination of dry NaOH and CM appears the most suitable and interesting pretreatment for the production of bioethanol from SB. © 2015 Elsevier Ltd.


PubMed | Charles Gerhardt Institute, CNRS Agropolymers Engineering and Emerging Technologies and INSA Toulouse
Type: | Journal: Bioresource technology | Year: 2016

Cellulosic pulps have been successfully isolated from wheat straw through a Lewis acids organosolv treatment. The use of Lewis acids with different hardness produced pulps with different delignification degrees. The cellulosic residue was characterised by chemical composition, X-ray diffraction, FT-IR spectroscopy, N2 physisorption, scanning electron microscopy and potential for anaerobic digestibility. Surface area and pore volume increased with the hardness of the Lewis acid, in correspondence with the decrease of the amount of lignin and hemicellulose in the pulp. The non linearity of the correlation between porosity and composition suggests that an agglomeration of cellulose fibrils occurs in the early stages of pulping. All organosolv pulps presented a significantly higher methane potential than the parent straw. A methane evolution of 295Ncm(3)/g OM was reached by a moderate improvement of the accessibility of the native straw.


Barakat A.,CNRS Agropolymers Engineering and Emerging Technologies | Jerome F.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources | Rouau X.,CNRS Agropolymers Engineering and Emerging Technologies
ChemSusChem | Year: 2015

License to mill: Proteins were continuously extracted from polysaccharides, lignin, and polyphenol by combining ultrafine milling with electrostatic separation. Such a fractionation process does not involve any solvent, catalyst, or external source of heating. In addition, this dry process is compatible with downstream enzymatic reactions, thus opening an attractive route for producing valuable chemicals from biomass. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


PubMed | CNRS Agropolymers Engineering and Emerging Technologies, Montpellier SupAgro and University of Wisconsin - Madison
Type: Journal Article | Journal: MicrobiologyOpen | Year: 2015

Antimicrobial peptides represent an expanding family of peptides involved in innate immunity of many living organisms. They show an amazing diversity in their sequence, structure, and mechanism of action. Among them, plant defensins are renowned for their antifungal activity but various side activities have also been described. Usually, a new biological role is reported along with the discovery of a new defensin and it is thus not clear if this multifunctionality exists at the family level or at the peptide level. We previously showed that the plant defensin AhPDF1.1b exhibits an unexpected role by conferring zinc tolerance to yeast and plant cells. In this paper, we further explored this activity using different yeast genetic backgrounds: especially the zrc1 mutant and an UPRE-GFP reporter yeast strain. We showed that AhPDF1.1b interferes with adaptive cell response in the endoplasmic reticulum to confer cellular zinc tolerance. We thus highlighted that, depending on its cellular localization, AhPDF1.1b exerts quite separate activities: when it is applied exogenously, it is a toxin against fungal and also root cells, but when it is expressed in yeast cells, it is a peptide that modulates the cellular adaptive response to zinc overload.

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