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International audience; D-Xylose is the main constituent of hemicelluloses, the second most abundant polysaccharide in nature after cellulose. Thus, the β-xylopyranose motif is widely distributed in the plant kingdom. On the contrary, D-xylose is an unusual carbohydrate in mammalian cells, only present in the structures of proteoglycans, macromolecules with important biological functions. In recent years, β-xylopyranosides have attracted renewed interest due to the development of biomass-derived molecules and their numerous applications. In this review, we will first focus on general routes for the preparation of β-xylopyranosides according to the nature of the glycosidic linkage and the aglycone moiety by chemical and enzymatic pathways. The main uses of these molecules for different applications, such as activators in the biosynthesis of glycosaminoglycans, for enzyme inhibition and as surfactants will be presented.

International audience; Synthesis of bio-based molecules from plant biomass with chemoenzymatic pathways represents a challenging task for the development of green chemistry. In this context, an efficient two-step chemoenzymatic sequence has been achieved for the preparation of triazole-linked xylosides and xylobiosides from biomass-derived xylans. The synthesis of propargyl xyloside and xylobioside catalysed by a xylanase in an aqueous medium was first studied and improved according to different reaction parameters. Cycloaddition reactions between the terminal alkyne moiety of these xylosides or xylobiosides and various aliphatic, aromatic or functionalized azides ("click chemistry") afforded various triazole-linked O-xylosides and O-xylobiosides in high yields. These molecules are of interest for different biological applications.

A renewable bisepoxide, SYR-EPO, was prepared from syringaresinol, a naturally occurring bisphenol deriving from sinapic acid, by using a chemo-enzymatic synthetic pathway. Estrogenic activity tests revealed no endocrine disruption for syringaresinol. Its glycidylation afforded SYR-EPO with excellent yield and purity. This biobased, safe epoxy precursor was then cured with conventional and renewable diamines for the preparation of epoxy-amine resins. The resulting thermosets were thermally and mechanically characterized. Thermal analyses of these new resins showed excellent thermal stabilities (T-d5%=279-309 degrees C) and T-g ranging from 73 to 126 degrees C, almost reaching the properties of those obtained with the diglycidylether of bisphenol A (DGEBA), extensively used in the polymer industry (T-d5%= 319 degrees C and T-g = 150 degrees C for DGEBA/isophorone diamine resins). Degradation studies in NaOH and HCl aqueous solutions also highlighted the robustness of the syringaresinol-based resins, similar to bisphenol A (BPA). All these results undoubtedly confirmed the potential of syringaresinol as a greener and safer substitute for BPA

Members of the genus Burkholderia colonize diverse ecological niches. Among the plant-associated strains, Paraburkholderia phytofirmans PsJN is an endophyte with a broad host range. In spatially structured environment (unshaken broth cultures), biofilm-constructing specialists of P. phytofirmans PsJN colonizing the air-liquid interface arose at high frequency. In addition to forming a robust biofilm in vitro and in planta on Arabidopsis roots, those mucoid phenotypic variants display a reduced swimming ability and modulate the expression of several Microbe Associated Molecular Pattern (MAMPs) including exopolysaccharides (EPS), flagellin and GroEL. Interestingly, the variants induce a low PR1 and PDF1.2 expression compared to the parental strain, suggesting a possible evasion of plant host immunity. We further demonstrated that switching from the planktonic to the sessile form did not involve quorum-sensing genes but arose from spontaneous mutations in two genes belonging to an Iron-Sulfur Cluster: hscA (encoding a co-chaperone protein) and iscS (encoding a cysteine desulfurase). A mutational approach validated the implication of these two genes in the appearance of variants. We showed for the first time that in heterogeneous environment, P. phytofirmans strain PsJN is able to rapidly diversify and co-express a variant that outcompete the wild-type form in free-living and static conditions but not in planta . IMPORTANCE Paraburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneaous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilm in vitro and in planta and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneaous mutations in an Iron-Sulfur Cluster. Overall, the data provided here allowed a better understanding of the adaptive mechanisms likely developed by P. phytofirmans PsJN in heterogeneous environment.

Determining the foraging niche of wild species is a challenging task, recently overcome through DNA metabarcoding. This method is successfully used to identify ingested food items of faecal samples. However, several limitations can affect the output of this method. Here, two benchtop high-throughput sequencing (HTS) platforms were evaluated, the Ion PGM (Life Technologies) and the MiSeq (Illumina). We assessed their ability to identify a large taxonomic array of food items for species having a diet possibly containing human-processed products and prey items. We sequenced faecal DNA samples obtained from domestic cats Felis silvestris catus, generalist carnivores presenting numerous specific DNAs in their diet. We assessed platform sensitivity and data reproducibility using both a cat fed on a controlled mixed diet along with a calibration study and free-ranging individuals sampled from a rural area. All the samples were analysed in independent PCR duplicates on each platform. The results of the calibration study showed that the output from MiSeq was more sensitive and reproducible than that from Ion PGM. Detection variability was linked to DNA degradation: 82% of the expected occurrences were detected for intact preys, versus 54% for pet food and 31% for out-of-date raw fish and meat. The Ion PGM detected significantly less human-linked food, birds, field voles, murids and shrews in the field-collected samples than the MiSeq platform. Pooling the replicates from both platforms and filtering HTS data allowed identifying at least one food item in 87.4% of the 326 field-collected samples. A total of 29 prey taxa (90% at species level) and 33 human-related food taxa (76% at genus level) were identified. The findings indicate that using HTS platforms such as MiSeq, which provide reads of sufficiently high quantity and quality, with sufficient numbers of technical replicates, is a robust and non-invasive approach to determine diet composition in animals foraging on a wide range of items in anthropogenic landscapes.

The main research questions of the SmartArt project concern the social inclusion of visually impaired people and the emotional relationship with art works. The hypothesis is that a key element of the relationship with art, regardless of visual capabilities, is the emotional resonance of the piece of art with the soul. The objective of the project is the design and organization of an exhibition and an animation program aimed at translating the visual emotion of the artwork into tactile emotion, adapted to the needs of the visually impaired, but which would appeal to everyone. This deliverable presents the research carried out by the team of the University of Technology of Troyes with the SAVS Michel Fandre between January and June 2017. It presents the needs analysis - the approach, the methods used and the results - formalizes the main findings of this research, as well as the specifications for the future exhibition, which will be the culmination of the SmartArt project, and will be held at the Musée de l'Ardenne from June to September 2018.; Les principaux questionnements de recherche du projet SmartArt portent sur l’inclusion sociale des personnes déficientes visuelles, et le rapport émotionnel à l’œuvre. L'hypothèse est qu’un élément clé de la relation avec l'art, indépendamment des capacités visuelles, est la résonance émotionnelle de l'art avec le moi. L’objectif du projet est la conception et l’organisation d’une exposition finale, et d’un programme d’animation visant à traduire l’émotion visuelle de la toile en émotion tactile, qui soit adaptée aux besoins des personnes déficientes visuelles, et qui s'adresserait à tout un chacun. Ce livrable présente la recherche menée par l’équipe de l’Université de technologie de Troyes avec le S.A.V.S Michel Fandre, entre janvier et juin 2017. Il présente l’analyse des besoins - la démarche, les méthodes utilisées ainsi que les résultats - qui formalise les principales connaissances dégagées par cette recherche, ainsi que le cahier des charges. L’objectif du cahier des charges est d’informer la conception de l’exposition finale, qui sera l’aboutissement du projet SmartArt, et qui se tiendra au Musée de l’Ardenne de juin à septembre 2018.

The main research questions of the SmartArt project concern the social inclusion of visually impaired people and the emotional relationship with art works. The hypothesis is that a key element of the relationship with art, regardless of visual capabilities, is the emotional resonance of the piece of art with the soul. The objective of the project is the design and organization of an exhibition and an animation program aimed at translating the visual emotion of the artwork into tactile emotion, adapted to the needs of the visually impaired, but which would appeal to everyone. This deliverable presents the research carried out by the team of the University of Technology of Troyes with the SAVS Michel Fandre between January and June 2017. It presents the needs analysis - the approach, the methods used and the results - formalizes the main findings of this research, as well as the specifications for the future exhibition, which will be the culmination of the SmartArt project, and will be held at the Musée de l'Ardenne from June to September 2018.; Les principaux questionnements de recherche du projet SmartArt portent sur l’inclusion sociale des personnes déficientes visuelles, et le rapport émotionnel à l’œuvre. L'hypothèse est qu’un élément clé de la relation avec l'art, indépendamment des capacités visuelles, est la résonance émotionnelle de l'art avec le moi. L’objectif du projet est la conception et l’organisation d’une exposition finale, et d’un programme d’animation visant à traduire l’émotion visuelle de la toile en émotion tactile, qui soit adaptée aux besoins des personnes déficientes visuelles, et qui s'adresserait à tout un chacun. Ce livrable présente la recherche menée par l’équipe de l’Université de technologie de Troyes avec le S.A.V.S Michel Fandre, entre janvier et juin 2017. Il présente l’analyse des besoins - la démarche, les méthodes utilisées ainsi que les résultats - qui formalise les principales connaissances dégagées par cette recherche, ainsi que le cahier des charges. L’objectif du cahier des charges est d’informer la conception de l’exposition finale, qui sera l’aboutissement du projet SmartArt, et qui se tiendra au Musée de l’Ardenne de juin à septembre 2018.

International audience; In this study, ferulic acid - a natural phenolic acid present in bagasse, wheat and rice brans, and beetroot pulp - was used as renewable starting material to prepare new biobased epoxy precursors. This biobased building block was first esterified then reduced to provide ethyl dihydroferulate which was then transesterified/amidified with biobased diols, triol and diamines. Immobilized Candida antarctica (aka CAL-B or Novozyme 435 (R)) was used to perform the solvent-free-transesterification/amidation under mild conditions. The phenolic architectures synthesized were then glycidylated using a TEBAC-mediated procedure to afford four biobased epoxy precursors- with various linker structures between the ferulic units which were then cured with conventionnal and biobased diamine curing agents. The thermal and thermomechanical properties of the thermosets prepared were assessed by TGA, DSC and DMA to highlight the influence of the linker configuration (aliphatic vs cycloaliphatic), that of the epoxy functionality (di vs tri), and that of the nature of the function used for coupling ferulic units (ester vs amide) on the thermosets properties. Analyses of these thermosets revealed glass transition temperatures ranging from 32 to 85 degrees C and high thermal stabilities around 300 degrees C. The mechanical behavior of the biobased thermosets proved equivalent to that of the DGEBA-IPDA reference sytem at low temperatures (up to 40-100 degrees C depending on the epoxy precursor and diamine).

International audience; In the context of replacement of petro-sourced and toxic bisphenol A (BPA), syringaresinol, a naturally occurring bisphenol deriving from sinapic acid, has been proposed as a greener and safer alternative. This work focuses on its applications for nonisocyanate polyurethane (NIPU) synthesis. A five membered cyclic carbonate SYR-CC has been prepared by carbon dioxide addition to bis-epoxy monomer SYR-EPO derived from syringaresinol. Upon polyaddition of SYR-CC with different biosourced and petrosourced diamines, the resulting polyhydroxyurethanes were fully characterized by structural (Fourier transform infrared, 'H nuclear magnetic resonance, high performance liquid chromatography size exclusion chromatography) and thermal analyses (thermogravimetric analysis, differential scanning calorimetry). These thermoplastics displayed high molar mass (M-n = 5.4 kg mo1(-1)), excellent thermal stabilities (T-d5% = 267 - 281 degrees C) and glass transition temperatures (T-g) ranging from 63 to 98 degrees C. The coupling of SYR-CC with a triamine gave thermoset material with interesting T-g (62 degrees C) and high thermal stability (T-d5% = 225 degrees C).

International audience; We report herein an optimized biocatalytic oxidative process for the synthesis of syringaresinol from sinapyl alcohol at a multigram scale (93% yield) in very high yield. Syringaresinol thereby obtained is of sufficient chemical purity and exhibits good thermal and antiradical activities to be used without further purification in many applications related to polymer synthesis as an alternative to bisphenol A. Different mechanistic pathways were discussed to better understand the impact of reaction conditions on the type of linkage formed during the oxidative process. Antiradical activity (DPPH analysis) and thermal properties of syringaresinol are also discussed.

International audience; Chiral epoxides—such as ethyl and methyl (S)-3-(oxiran-2-yl)propanoates ((S)-1a/1b)—are valuable precursors in many chemical syntheses. Until recently, these compounds were synthesized from glutamic acid in four steps (deamination, reduction, tosylation and epoxide formation) in low to moderate overall yield (20%–50%). Moreover, this procedure requires some harmful reagents such as sodium nitrite ((eco)toxic) and borane (carcinogen). Herein, starting from levoglucosenone (LGO), a biobased chiral compound obtained through the flash pyrolysis of acidified cellulose, we propose a safer and more sustainable chemo-enzymatic synthetic pathway involving lipase-mediated Baeyer-Villiger oxidation, palladium-catalyzed hydrogenation, tosylation and treatment with sodium ethoxide/methoxide as key steps. This route afforded ethyl and methyl (S)-3-(oxiran-2-yl)propanoates in 57% overall yield, respectively. To demonstrate the potentiality of this new synthetic pathway from LGO, the synthesis of high value-added (S)-dairy lactone was undertaken from these epoxides and provided the target in 37% overall yield from LGO.

International audience; Cellulose-derived levoglucosenone (LGO) has been efficiently converted into pure (S)-γ-hydroxymethyl-α,β-butenolide (HBO), a chemical platform suited for the synthesis of drugs, flavors and antiviral agents. This process involves two-steps: a lipase-catalyzed Baeyer-Villiger oxidation of LGO followed by an acid hydrolysis of the reaction mixture to provide pure HBO. Response surface methodology (RSM), based on central composite face-centered (CCF) design, was employed to evaluate the factors effecting the enzyme-catalyzed reaction: pka of solid buffer (7.2–9.6), LGO concentration (0.5–1 M) and enzyme loading (55–285 PLU.mmol-1). Enzyme loading and pka of solid buffer were found to be important factors to the reaction efficiency (as measured by the conversion of LGO) while only the later had significant effects on the enzyme recyclability (as measured by the enzyme residual activity). LGO concentration influences both responses by its interaction with the enzyme loading and pka of solid buffer. The optimal conditions which allow to convert at least 80% of LGO in 2 h at 40°C and reuse the enzyme for a subsequent cycle were found to be: solid buffer pka = 7.5, [LGO] = 0.50 M and 113 PLU.mmol-1 for the lipase. A good agreement between experimental and predicted values was obtained and the model validity confirmed (p < 0.05). Alternative optimal conditions were explored using Monte Carlo simulations for risk analysis, being estimated the experimental region where the LGO conversion higher than 80% is fulfilled at a specific risk of failure.

BACKGROUND: Reactive liquid-liquid extraction is a promising technique for the direct recovery of carboxylic acids from bioconversion media. This work focused on the optimization of 3-hydroxypropionic acid (3-HP) reactive extraction assisted by hollow-fiber membrane contactor (HFMC), using tri-n-octylamine (TOA) and Aliquat 336 as extractants in n-decanol, and on its practical application for the recovery of 3-HP obtained from glycerol bioconversion by Lactobacillus reuteri. RESULTS: The results underlined the influence of the initial pH and 3-HP concentration of the aqueous medium and the impact of extractant phase composition on the extraction performances. The highest distribution coefficient of 3-HP (K-D = 13.0) was observed at pH = 3 with 10% v/v TOA mixed with 10% v/v Aliquat 336 in n-decanol. This study showed that the acid concentration and the ratio of amines used between TOA and Aliquat 336 in n-decanol did not have a great impact on the K-D during 3-HP reactive extraction, whereas it had an influence on the extraction kinetics. Moreover, 3-HP reactive extraction assisted by HFMC from real bioconversion broth with glycerol as the substrate was shown to be feasible, with the same order of magnitude of extraction kinetics but with a lower K-D compared with reactive extraction using model broth. CONCLUSIONS: 3-HP was predominantly extracted from the bioconversion broth, confirming the high selectivity of the extraction process studied and the high potential of this approach applied to the biotechnological production of 3-HP.

In this work, a series of bio-based chemically recyclable epoxy resins were synthesized from n-alkyl bis-ferulate esters that do not activate human estrogen receptor alpha (ERa). Viscosities of corresponding glycidyl ether n-alkyl bisferulate resins, determined by steady shear rheology, range from 12-9.4 Pa s. Activation energies of flow range from 83-96 kJ mol(-1) and are similar to the diglycidyl ether bisphenol A (DGEBA). Thermomechanical properties of diglycidyl ether n-alkyl bisferulate resins cured with isophorone diamine were governed by the length of alpha,omega-diols that link glycidyl ether ferulate units. That is, the glassy phase modulus and alpha transition temperatures range from 3400-2400 MPa (at 25 degrees C) and 40-53 degrees C (peak of E''), respectively. Furthermore, the onset of thermal degradation (T-d5%) varied from 331-300 degrees C. Chemical recycling of cured epoxy resins was performed by static immersion in 10 w/w sodium hydroxide aqueous solutions at 60 degrees C. Times required for complete conversion of cured resins to water-soluble degradation products was also alpha,omega-diol length dependent and varied from 5 to 65 h. Thus, diglycidyl ether of n-alkyl bisferulate resins provides a viable biobased alternative to BPA epoxy resins as well as the option of chemical degradability and recovery of fillers in composite applications.

International audience; BACKGROUNDBioconversion is a promising route to produce bio‐based building blocks such as 3‐hydroxypropionic acid (3‐HP). Reactive extraction can be used for 3‐HP recovery, and ultimately integrated to the bioconversion process. To the best of our knowledge, there is no published experimental data about the reactive extraction of 3‐HP. This work aimed to study the extraction of 3‐HP using tri‐n‐octylamine and Aliquat 336 as extractants in n‐decanol. Comparison was also made with its positional isomer, lactic acid. Finally, the extraction of 3‐HP from model and real bioconversion broths was examined.RESULTSThe use of mixed extractants showed high performances over a wide range of experimental conditions, highlighting a synergistic effect. A possible extraction mechanism considers the formation of a ternary complex between TOA, Aliquat 336 and the carboxylic acid. When 3‐HP was extracted from a real bioconversion broth, some cell‐originating compounds were suspected to adsorb to the aqueous–organic interface. This effect, added to the possible competition between 3‐HP and compounds that can react with the extractants, led to limitations in the yield (Y%) and selectivity (α3HP) of the extraction. For example, Y% and α3HP were respectively 89% and 35.9 for the model bioconversion broth and decreased to 62% and 15.7 for the real broth at pH = 3.2.CONCLUSIONEffective experimental conditions for the reactive extraction of 3‐HP were pointed out for the first time. Further work will be undertaken with a view to better elucidating the mechanisms involved in real conditions of an integrated extractive bioconversion system.

International audience; Renewable α,ω-dienes have been prepared from syringaresinol, a naturally occurring bisphenol deriving from sinapyl alcohol, and further studied as monomers in ADMET polymerizations. Polymerization was optimized according to catalyst loading and reaction conditions (in mass vs. in solvent), and led to polymers with molecular weight up to 14.1 kDa. Thermal analyses of these new polymers showed excellent thermal stabilities (257–360 °C) and tunable Tg (18–70 °C) depending on the structure of the starting α,ω-diene monomer.

The aims of this study is to compare the growth and glucose metabolism of three Lactobacillus reuteri strains (i.e. DSM 20016, DSM 17938, and ATCC 53608) which are lactic acid bacteria of interest used for diverse applications such as probiotics implying the production of biomass, or for the production of valuable chemicals (3-hydroxypropionaldehyde, 3-hydroxypropionic acid, 1,3-propanediol). However, the physiological diversity inside the species, even for basic metabolisms, like its capacity of acidification or glucose metabolism, has not been studied yet. In the present work, the growth and metabolism of three strains representative of the species diversity have been studied in batch mode. The strains were compared through characterization of growth kinetics and evaluation of acidification kinetics, substrate consumption and product formation. The results showed significant differences between the three strains which may be explained, at least in part, by variations in the distribution of carbon source between two glycolytic pathways during the bacterial growth: the phosphoketolase or heterolactic pathway (PKP) and the Embden-Meyerhof pathway (EMP). It was also shown that, in the context of obtaining a large amount of biomass, DSM 20016 and DSM 17938 strains were the most effective in terms of growth kinetics. The DSM 17938 strain, which shows the more significant metabolic shift from EMP to PKP when the pH decreases, is more effective for lactate production.

Chemo-enzymatic synthesis and screening of a library of renewable saturated and unsaturated bis- and trisphenols deriving from p-hydroxycinnamic acids (i.e., p-coumaric acid, ferulic acid, and sinapic acid) and biobased diols/triol (i.e., isosorbide, 1,4-butanediol, glycerol) showed that these compounds were potent antioxidants/antiradicals. To optimize their antiradical activities, we assessed the structure activity relationships (SAR) of these phenolics focusing on the internal diol/triol linker, the degree of methoxylation on the aromatic rings, and the C=C double bond of the alpha,beta-unsaturated esters. We found that methoxylation degree and the unsaturation were critical for antiradical activity while the nature of the diol had a small impact. Indeed, SAR revealed that, for saturated compounds, the higher the methoxylation degree, the higher the antiradical activity; on the other hand, unexpectedly, the presence of the unsaturation had a negative impact on the activity. The antiradical activities of these bis- and trisphenols were then compared to that of Irganox 1010, a widely used antioxidant additive in polypropylene. The optimized compounds, i.e. those deriving from sinapic acid and with saturated esters, proved as effective while being 100% biobased and obtained through a more sustainable synthetic pathway. Thermal analyses (TGA) demonstrated that these bis- and trisphenols exhibit high thermal stability and that their T(d)5% can be easily tailored by playing with the structure of the bisphenol core. p-Hydroxycinnamic acids-based bis- and trisphenols are thus promising easily accessible, eco-friendly, and biocompatible antiradical additives for a sustainable approach to the stabilization of polymers in packaging and other applications.

Active packaging is a term that refers to the use of package to do more than merely protect the food from the outside environment. Amongst active packaging, oxygen scavengers can prevent oxidative damage to flavour and colour in a wide range of foods. They offer advantages in maintaining quality and extending shelf life. We thus present the use of a cobalt(II) complex with the ligand l-threonine as a new oxygen scavenger. This complex, in addition to its high reactivity with oxygen after water activation, can be obtained easily in large amounts and does not react with oxygen in solid state. Thus, the incorporation of the Co(II)(l-Thr)(2)(OH2)(2) natural complex in organic polar polymer (poly(vinyl alcohol)) by casting process was conducted. The reactivity towards oxygen of the obtained films was evaluated by oxidation kinetics monitoring using ultraviolet-visible spectrophotometry as a function of time and relative humidity. Oxygen consumption of the active film was found equal to the complex alone (2.5mg of O-2 per gramme of complex) after water activation (90.5% relative humidity). Copyright (c) 2014 John Wiley & Sons, Ltd.

International audience; Composites made of polycaprolactone reinforced by 20% hemp fibres were prepared by melt blending in a twin screw extruder (TSE). The influence of the extrusion parameters (feed rate and screw speed) on the fibre length evolution along the screw profile was investigated. The fibre length rapidly decreased after the introduction of the fibres and during the flow through the kneading blocks. Fibre fragmentation was increased at high screw speeds and low feed rates. The flow conditions along the TSE were calculated using Ludovic© software, focusing on the specific mechanical energy (SME) provided to the fibres. The fibre length evolution can be correctly estimated for various flow conditions using an exponential function of the SME.

International audience; The role of flagellin perception in the context of plant beneficial bacteria still remains unclear. Here, we characterized the flagellin sensing system flg22-FLAGELLIN SENSING 2 (FLS2) in grapevine, and analyzed the flagellin perception in the interaction with the endophytic plant growth-promoting rhizobacterium (PGPR) Burkholderia phytofirmans. The functionality of the grapevine FLS2 receptor, VvFLS2, was demonstrated by complementation assays in the Arabidopsis thaliana fls2 mutant, which restored flg22-induced H2O2 production and growth inhibition. Using synthetic flg22 peptides from different bacterial origins, we compared recognition specificities between VvFLS2 and AtFLS2. In grapevine, flg22-triggered immune responses are conserved and led to partial resistance against Botrytis cinerea. Unlike flg22 peptides derived from Pseudomonas aeruginosa or Xanthomonas campestris, flg22 peptide derived from B. phytofirmans triggered only a small oxidative burst, weak and transient defense gene induction and no growth inhibition in grapevine. Although, in Arabidopsis, all the flg22 epitopes exhibited similar biological activities, the expression of VvFLS2 into the fls2 background conferred differential flg22 responses characteristic for grapevine. These results demonstrate that VvFLS2 differentially recognizes flg22 from different bacteria, and suggest that flagellin from the beneficial PGPR B. phytofirmans has evolved to evade this grapevine immune recognition system.

The GH39 beta-xylosidase from Bacillus halodurans (BhXy139) was previously reported to catalyze the synthesis of alkyl xylosides from donors such as pNP beta-D-xylopyranoside or xylobiose and from aliphatic alcohols acting as acceptors with chain length inferior to five carbons. In the present study, the role played by aromatic residues present in the aglycone binding subsite of BhXy139 in the hydrolysis and transglycosylation reactions of the enzyme was investigated. In this way, site-directed mutagenesis was carried out in order to highlight the role of three targeted hydrophobic residues F116, F167 and Y284. These residues were replaced by alanine to decrease the steric hindrance or were mutated into serine to evaluate the impact of the presence of a polar residue into the aglycone binding subsite of BhXy139. Taking into account kinetic parameters and yields of transglycosylation, the function of each mutated residue in the catalytic mechanism was studied. Results concerning transglycosylation reactions in the presence of pentan-1-ol and octan-1-ol indicated that yields of transglycosylation were impacted both by the position and the nature of the mutated residues. These results were consistent with molecular docking performed with both acceptors which notably confirms that among the three targeted residues, F116 represents the most interesting one for mutagenesis to increase the transglycosylation reactions in presence of long chain alcohols. (C) 2013 Elsevier B.V. All rights reserved.

Hydrocarbon-like coatings were deposited on different biodegradable polyesters from renewable (bio-based) and non-renewable (fossil-based) resources, such as homopolymers (polylactic acid - PLA, polycaprolactone - PCL) and copolymers (Polyhydroxybutyrate-co-hydroxyvalerate - PHBV, polybutylene adipate-co-terephthalate - PBAT), respectively. The coated samples were tested in terms of adhesion and barrier properties, fragmentation tests, roughness, surface composition and water contact angle measurements. Depending on the substrate, these properties exhibit different behaviours. The coating adhesion of PCL or PHBV is twice higher than the adhesion of coated PLA or PBAT, and depends on the substrate. Barrier performances were mainly improved for both coated PCL and PHBV. Different behaviours are assigned to the change of substrate nature, which induces different interface structure and composition. (C) 2012 Elsevier Ltd. All rights reserved.

International audience; To predict the environmental benefits of energy crop production and use, the nature and fate of biomass residues in the soil need to be quantified. Our objective was to quantify Miscanthus x giganteus biomass recycling to soil and to assess how harvesting time and N fertilization affect their characteristics and subsequent biodegradability. The quantification of aerial and belowground biomass and their sampling were performed on 2- and 3-year-old Miscanthus stands, either fertilized with 120 kg N ha(-1) year(-1) or not fertilized, in autumn (maximal biomass production) and winter (maturity). Plant biomass was chemically characterized (total sugars, Klason lignin, C/N) and incubated in optimum decomposition conditions (15A degrees C, -80 kPa) for 263 days, for C and N mineralization. Accumulation of carbon in rhizomes and roots was 7.5 to 10 t C ha(-1) and represented about 50% of total plant biomass C. Senescent leaves represented about 1.5 t C ha(-1) year(-1). All residues, especially the roots, had high lignin contents, while the rhizomes also had a high soluble content due to their nutrient storage function. The C mineralization rates were closely related to the chemical characteristics of the residue, higher sugar and lower lignin contents leading to faster decomposition, as observed for rhizomes.

International audience

International audience; Hydrolysis of TA photoproduct leads to two derivatives presenting different formation kinetic profiles depending on the oligomer content. The formation efficiency of TA photoproducts in UV-C-irradiated DNA slightly exceeds the formation of the trans,syn cyclobutane pyrimidine dimer at TT sites.

This article is focused on the analysis of the structure-process relationships of biodegradable materials. It is mainly focused on the analysis of phase separation phenomenon occurring during the extrusion of plasticized starch/polycaprolactone blends, in a slit die. Rheological characterizations are carried out, in-line in an instrumented slit die at the exit of the extruder and, out-line with different rheometers. In certain conditions, a pseudo-multilayer structure can be generated with a polyester rich skin. Then, Electron Spectroscopy for Chemical Analysis (ESCA) and Fourier Transformed Infrared Attenuated Total Reflectance (FTIR-ATR) analyses are conducted to evaluate semi-quantitatively the polyester surface enrichment. In the range of available shear rates, the phase separation is mainly driven by the molecular weight of polycaprolactone, linked to its molten state viscosity. Three zones of surface enrichment, dependent on the molecular weights, are identified. Above 60,000 g·mol−1, no surface enrichment could be detected; below 37,000 g·mol−1, the phase separation occurs with no dependence on the processing conditions; between these two limits, the phase separation depends on both, the formulation and the processing conditions. A correlation between the rheological measurements and the phase separation is given. A predictive criterion based on the viscous behavior of the blend is established. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

International audience; Rate coefficients for the gas-phase reactions of Cl atoms with three isomers of dimethylbenzaldehyde (DMBs) have been determined using the relative rate method. Relative rate measurements were performed in a Teflon reaction chamber at 298 ± 3 K and atmospheric pressure. The rate constants obtained (10−11 cm3 molecule−1 s−1) were, respectively, 8.8 ± 1.7, 9.5 ± 1.4 and 9.6 ± 1.6 for 2,4-DMB, 2,5-DMB and 3,5-DMB. This work provides the first kinetic determination of the gas-phase reactions of Cl atoms with DMBs. Our results are compared with the OH reaction with the same DMBs and discussed in terms of structure-reactivity relationship and the atmospheric impact of DMBs.