References of "Richel, Aurore"
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See detailMediterranean agri-food processing wastes pyrolysis after pre-treatment and recovery of precursor materials: A TGA-based kinetic modeling study
Manara, Panagiota; Vamvuka, V; Sfakiotakis, S et al

in Food Research International (in press)

Valorization strategies of wastes from agri-food processes are intertwined with clean technological approaches and eco-industrial management. By-products from Mediterranean agri-food processes such as ... [more ▼]

Valorization strategies of wastes from agri-food processes are intertwined with clean technological approaches and eco-industrial management. By-products from Mediterranean agri-food processes such as olive oil, wine and fruit create a considerable disposal problem for the agro-industry. Their characteristics in combination with Mediterranean climate enhance microbial development and can be source of health and safety concerns. After pre-treatment and recovery of valuable precursor materials (lignin, pulp), pyrolysis can be used for fuels, chemicals and carbon bio-based materials production. Since thermal degradation kinetic studies are a key step for the efficient design of thermo-chemical processes, in this study pyrolysis experiments were performed, using TGA for the estimation of the process kinetic parameters. The independent parallel reaction model validat- ed against experimental results, showing a good agreement with experimental data, with deviation values rang- ing from 1.07 to 3.54%. [less ▲]

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See detailEnzymatic hydrolysis of softwood and hardwood regenerated celluloses
Jacquet, Nicolas ULg; Maniet, Guillaume ULg; Richel, Aurore ULg et al

in Current Chemical Biology (in press)

Regenerated celluloses from Kraft wood pulps (from hardwoods and softwoods) were hydrolysed by mean of cellulase of Trichoderma reesei. Our results highlighted that a 75% hydrolysis yield was reached for ... [more ▼]

Regenerated celluloses from Kraft wood pulps (from hardwoods and softwoods) were hydrolysed by mean of cellulase of Trichoderma reesei. Our results highlighted that a 75% hydrolysis yield was reached for hardwood regenerated cellulose (HRC) and 90% for softwood regenerated cellulose (SRC). Crystallinity indices from X-Ray diffraction patterns were used to measure hydrolysis rate of crystalline and amorphous regions. Addition of β-glucosidase to the enzymatic complex of Trichoderma reesei was confirmed to enhance yields of hydrolysis. [less ▲]

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See detailMicrowave-assisted thermochemical and primary hydrolytic conversions of lignocellulosic resources: a review
Richel, Aurore ULg; Jacquet, Nicolas ULg

in Biomass Conversion and Biorefinery (in press)

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as promising renewable alternatives. Particularly, the conversion of lignocellulosic materials has ... [more ▼]

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as promising renewable alternatives. Particularly, the conversion of lignocellulosic materials has nowadays opened new vistas for the production of energy, biofuels and chemicals. In this literature review, microwave technology is described as an original heating source either for the thermochemical conversions (at temperatures up to 400°C) of lignocellulose into biofuels or the pretreatment (below 400°C) and further hydrolysis of lignocellulose into bioethanol and other valuable chemicals. Advantages of microwave approaches include a commonly observed acceleration in reaction rate and improved selectivities and yields. [less ▲]

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See detailSustainable Chemistry
Gillet, Sébastien ULg; Jacquet, Nicolas ULg; Richel, Aurore ULg

Learning material (2014)

1) Petrochemical and concept of biorefineries. 2) Biomass and biorefineries 3) Green Chemistry and Green Engineering

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See detailUse of 13C-NMR in structural elucidation of polysaccharides: case of locust bean gum
Gillet, Sébastien ULg; Aguedo, Mario ULg; Blecker, Christophe ULg et al

Poster (2014, November 25)

Locust bean gum (LBG) galactomannans are polysaccharides consisting of a β-(1→4) D-mannopyranosyl backbone substituted to varying degrees in α-(1→6) with single D-galactopyranosyl residues. This basic ... [more ▼]

Locust bean gum (LBG) galactomannans are polysaccharides consisting of a β-(1→4) D-mannopyranosyl backbone substituted to varying degrees in α-(1→6) with single D-galactopyranosyl residues. This basic structure is the same for all galactomannans (Fig. 2). However, when locust bean gum is extracted at different temperatures, the generated fractions exhibit different properties in aqueous solution (viscosity, viscoelasticity, gel formation, thermohydrolysis resistance, etc.). This means that there are differences within the fine structure of the polymers (although the basic structure is the same). Analysis of [13C]-NMR spectra of galactomannans, in combination with other techniques, can provide capital information about fine structural elucidation of the polymers. The method specifies the distribution of lateral galactosyls along the main chain of mannans. Two fractions extracted from locust bean gum at 25 and 80 °C (respectively GM25 and GM80) were comparatively studied by [13C]-NMR. Mannosyls/Galactosyls (M/G) ratios can be determined by considering the intensities of C-1 mannose and galactose signals in [13C]-NMR spectra. This method provides results relatively close to those obtained by GC-MS analysis. Spectra also showed that resonance from C4 of D-mannose residues were split, in evident dependence upon the nearest-neighbor probabilities (“diad frequencies”) of D-galactosyl groups along the mannan chains (Fig. 2). Diad frequencies were obtained by integrating C4(Man) peak areas. F11, F21/F12 and F22 gave respectively the di-, mono- or non-substituted mannose pairs proportions. High percentages of F11 and F22 therefore indicate a more non-homogeneous distribution of lateral galactosyls along the polysaccharide backbone as observed for GM80. The percentages of total lateral substituents obtained by C4(Man) peak analysis [F11 + (F21 or F12)/2] were fairly well correlated with M/G ratios. Splitting of the C-6 substituted D-mannose resonance provides, therefore the basis for determining the next-nearest-neighbor probabilities (triad frequencies) (Fig. 2). However, the spectrum is often not sufficiently resolved to accurately quantify and interpret the results. [less ▲]

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See detailImpact of steam explosion treatment on chemical configuration of Tall Fescue lignin : structural elucidation using NMR spectroscopy
Maniet, Guillaume ULg; Jacquet, Nicolas ULg; Gillet, Sébastien ULg et al

Poster (2014, November 24)

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass ... [more ▼]

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass could be used to produce high value products. To achieve this objective, pretreatment processes are required to allow the breakdown of lignocellulosic structure and increase accessibility of the material. In this way, steam explosion is a thermo-mechano-chemical pretreatment which allows the opening of lignocellulosic material structural components and includes modifications of the physical properties of the material, hydrolysis of hemicellulosic components and modification of the chemical structure of lignin [1]. This study is focused on the impact of various steam explosion treatments on the chemical configuration of tall fescue lignin. NMR analyses perform on the Festuca L. pretreated samples show variations of links with treatment intensity. Observations show double phenomen :re-polymerization and depolymerization of the lignin structure during steam explosion process [2]. In parallel, HPSEC analyses show modifications in the molecular weight of the lignin obtained after the steam explosion treatment. [less ▲]

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See detailBiorefining in Wallonia: towards a regional strategy for a biobased economy
Richel, Aurore ULg

Scientific conference (2014, November)

Many countries and regions in Europe are nowadays setting up biobased economy strategies and action plans. For Belgium, the case of the Walloon region is discussed in this talk through a SWOT analysis ... [more ▼]

Many countries and regions in Europe are nowadays setting up biobased economy strategies and action plans. For Belgium, the case of the Walloon region is discussed in this talk through a SWOT analysis. Even if a large part of the territory is covered by agricultural and forestry productions, the feedstock supply and availability are rather restricted. However, in order to stimulate the development of biorefineries in the Walloon region, it is important to support a reliable upstream supply chain. Therefore, several options are currently evaluated by the government, the industrial sectors and academic/research centers and presented herein through several pilot, R&D or industrial initiatives. [less ▲]

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See detailLes stratégies industrielles de valorisation de la biomasse végétale en Région Wallonne
Richel, Aurore ULg

Conference (2014, November)

Cet exposé décrit les stratégies industrielles de valorisation des matières premières végétales en Région Wallonne et les différences par rapport aux modèles européens et internationaux existants. Les ... [more ▼]

Cet exposé décrit les stratégies industrielles de valorisation des matières premières végétales en Région Wallonne et les différences par rapport aux modèles européens et internationaux existants. Les matières premières disponibles pour le bioraffinage de 1ère et 2ème générations sont listées sur base des données accumulées par les équipes de Gembloux Agro-Bio Tech. Les avantages et limitations de ces matières premières sont décrits. Les technologies de conversion commercialisables sont proposées en fonction des contraintes socio-économiques de la Wallonie: bioraffineries autonomes, intégrées, etc. Divers exemples de réalisations commerciales ou en prototypes sont proposés, de même que certains projets de R&D dans ce domaine. [less ▲]

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See detailEffects of Size and Dispersity of Microcrystalline Celluloses on Size, Structure and Stability of Nanocrystalline Celluloses Extracted by Acid Hydrolysis
Qi, Liu; Weiping, Hao; Yongguang, Yang et al

in Nano LIFE (2014), 4(4),

Nanocrystalline celluloses (NCCs) were separated from four commercial microcrystalline celluloses (MCCs) by an acid hydrolysis–sonication treatment. Transmission electron microscopy (TEM), atomic force ... [more ▼]

Nanocrystalline celluloses (NCCs) were separated from four commercial microcrystalline celluloses (MCCs) by an acid hydrolysis–sonication treatment. Transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectrum, X-ray di®raction (XRD) and thermogravimetric analysis (TGA) were conducted to investigate the NCCs. MCCs with di®erent morphologies and particle sizes showed di®erent aggregation degrees. The aggregation of MCCs followed the order MCC1 > MCC3 > MCC2 > MCC4, which is the same order of the heights of the resulting NCCs. The best uniformity and thermal stability were characterized for NCC3, which was produced by MCC3 with smallest original particle size and good dispersity among the four MCCs. This result suggests that both the original particle size and dispersity of MCCs had signi¯cant e®ects on separated NCCs. [less ▲]

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See detailChlorophyll: natural sources, extraction methods and application for textile industry
Miazek, Krystian ULg; Remacle, Claire ULg; Richel, Aurore ULg et al

Conference (2014, October 14)

Chlorophyll is a photosynthetic pigment available abundantly in microalgae and terrestrial plants. This pigment found applications in pharmaceutical, cosmetic and food products as a wound healing ... [more ▼]

Chlorophyll is a photosynthetic pigment available abundantly in microalgae and terrestrial plants. This pigment found applications in pharmaceutical, cosmetic and food products as a wound healing, antioxidant or coloring agent. Recent reports suggest that chlorophyll can also be used as a biomordant to enhance the dyeing process of textile products, but also as a textile dye with antimicrobial properties. In this presentation, different aspects of chlorophyll production are discussed. Firstly, numerous plant biomass types as potential sources of chlorophyll are presented. Subsequently, different methods for chlorophyll extraction and separation from plant biomass are described. Finally, possibilities of chlorophyll implementation into textile products on industrial scale are evaluated. [less ▲]

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See detailLa relation extraction-structure-propriétés des polysaccharides : cas des galactomannanes et des alginates
Gillet, Sébastien ULg; Richel, Aurore ULg

Learning material (2014)

Polysaccharides are usually composed of various monosaccharides linked with different glucosidic bonds. Some polysaccharides have hyperbranched structures. Moreover, polysaccharides often have high ... [more ▼]

Polysaccharides are usually composed of various monosaccharides linked with different glucosidic bonds. Some polysaccharides have hyperbranched structures. Moreover, polysaccharides often have high molecular weights, and tend to form aggregates in solution that can mask the behavior of individual macromolecules. In consequence, to characterize the chemical structures, chain conformations and physical properties of polysaccharides is not an easy task. [less ▲]

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See detailBatch enzymatic interesterification of fat blends using microwave
Danthine, Sabine ULg; Simon, C.; Richel, Aurore ULg et al

Poster (2014, September)

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See detailEffect of lignocellulose related compounds on microalgae growth and product biosynthesis: a review
Miazek, Krystian ULg; Remacle, Claire ULg; Richel, Aurore ULg et al

in Energies (2014), 7(2014), 4446-4481

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates ... [more ▼]

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, different treatment methods to hydrolyse lignocellulose into organic substrates are presented first. Secondly, the effect of lignocellulosic hydrolysates, organic substances typically present in lignocellulosic hydrolysates, as well as minor co-products, on growth and accumulation of target compounds in microalgae cultures is described. Finally, the possibilities of using lignocellulose hydrolysates as a common feedstock for microalgae cultures are evaluated. [less ▲]

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See detailGrowth of Chlorella in the presence of organic carbon: A photobioreactor study
Miazek, Krystian ULg; Goffin, Dorothée ULg; Richel, Aurore ULg et al

Scientific conference (2014, June 19)

In this study, the effect of organic carbon supplementation at low light intensity on Chlorella sorokiniana growth was evaluated. Addition of 1 g/L of acetate to media gave the highest growth rate and ... [more ▼]

In this study, the effect of organic carbon supplementation at low light intensity on Chlorella sorokiniana growth was evaluated. Addition of 1 g/L of acetate to media gave the highest growth rate and provided stable high biomass culture during prolonged cultivation time. Glucose at 1 – 5 g/L also improved biomass growth rate, although stability of high biomass culture could not be achieved. Overall, the presence of organic carbon can considerably enhance Chlorella growth when low light intensity is applied. [less ▲]

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See detailInhibitors of glycosylhydrolases as potential insecticides : focus on aphid model
Bosquée, Emilie ULg; Vandermoten, Sophie; Richel, Aurore ULg et al

Poster (2014, June)

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are ... [more ▼]

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are interesting to bring potential specific control of arthropods. Indeed, glycosylhydrolase group is very diversified from glucanases to trehalases, until chitinases. Different kinds of inhibitors were here tested to determine their potential role as new targetted aphicides. After different assays using the selected inhibitors in artificial diets, the most efficient molecules at 50-100 μg ml-1were kept for further proteomic tasks. The proteome patterns of aphids related to different inhibitor treatments were determined by two dimension electrophoresis, 2D-Differencial In Gel Expression (2D-Dige) coupled with mass spectrometry (ESI-MS-MS and Maldi-Tof-MS-MS) and data bank investigations. Particular proteins of interest were selected and accurately characterised with both fundamental but also applied views. Not only the carbohydrate metabolic pathway was disturbed with the use of glycosylhydolases inhibitors, other primary functions were also modified (amino acid synthesis, stress response, etc). This proteomic approach was discussed as an interesting and reliable tool to study the biologically involved proteins from aphids in response to specific tested enzymatic inhibitors with further ideas to be promoted as new insecticides to control insect pests. [less ▲]

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See detailA multi-step process for an alternative wheat bran biorefinery
Aguedo, Mario ULg; Fougnies, Christian; Richel, Aurore ULg

Poster (2014, May 21)

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See detailLa relation structure chimique-propriétés physiques des galactomannanes extraits de la caroube
Gillet, Sébastien ULg; Blecker, Christophe ULg; Paquot, Michel ULg et al

in Comptes Rendus Chimie (2014), 17(4),

Carob galactomannan fine chemical structure is closely related to the physical behavior developed in aqueous solution. Three elements of structural characterization are mainly described in the literature ... [more ▼]

Carob galactomannan fine chemical structure is closely related to the physical behavior developed in aqueous solution. Three elements of structural characterization are mainly described in the literature: the degree of galactose substitution, chain length, and galactose units distribution. This review article will attempt to highlight the impact of different structural features on physical properties such as solubility, viscosity, formation of hydrogels or gels in combination with other saccharides. The impact of industrial purification process on the structure and physical properties is also developed. [less ▲]

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See detailChemical Hydrolysis of Fagus sylvatica Wood: Dilute Acid vs. Alkaline Treatment
Miazek, Krystian ULg; Goffin, Dorothée ULg; Richel, Aurore ULg

Poster (2014, March 05)

Lignocellulosic biomass, found in a large variety of plants such as coniferous trees (Softwood), broad leaved trees (Hardwood), grasses and agricultural or food residues, is the most abundant source of ... [more ▼]

Lignocellulosic biomass, found in a large variety of plants such as coniferous trees (Softwood), broad leaved trees (Hardwood), grasses and agricultural or food residues, is the most abundant source of molecules required for production of biofuels and high value - added products. Lignocellulose is composed of three polymers: cellulose, hemicellulose and lignin. Cellulose is a non-branched polymer consisting of glucoses (hexoses). Hemicellulose is a complex carbohydrate containing pentoses (mainly xyloses in the case of Hardwood, grasses and agricultural wastes) or hexoses (usually mannoses in the case of Softwood) as the main sugars. Lignin is a biopolymer with aromatic alcohols as basic monomeric units. Cellulose chains are arranged in bundles and interlinked with hemicellulose. Lignin is cross-linked with hemicellulose and occupies space between cellulose bundles. Due to complex polymeric structure, lignocellulosic materials are resistant to hydrolysis. A number of treatment methods (mechanical, chemical, biochemical) is implemented to successfully hydrolyse lignocellulose. Amongst chemical methods harnessed to break lignocellulose structure, dilute acid and alkaline treatments are commonly mentioned, as the most efficient ones. The objective of this study was to evaluate the effect of dilute acid and alkaline treatment on hydrolysis rate of polymeric components in Fagus sylvatica wood. Fagus sylvatica also known as common beech is a broad leaved, deciduous tree that belongs to the family of Fagaceae, widely spread in Europe. Beech wood was determined to contain 48 % glucose, 18 % xylose and 20 % Klason lignin in its dry material. Results of this study showed that 1 h hydrolysis at 100 °C with the use of 3 % H2SO4 resulted in 71 % removal of xylose and 4 % removal of glucose with Klason lignin remained intact. Additionally, the presence of sugar degradation products: 2 - furfural and hydroxymethylfurfural was detected in dilute acid hydrolysate. Release of 2 - furfural and hydroxymethylfurfural from beech wood was determined as 0.03 % and 0.1 %, respectively. On the other hand, 1 h hydrolysis at 100 °C with the use of 7 % NaOH caused 59 % xylose removal and 11 % removal of Klason lignin with no effect on glucose. Dilute acid hydrolysis proved to be more efficient in removing xylose, but alkaline hydrolysis additionally showed to remove Klason lignin. [less ▲]

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