References of "Richel, Aurore"
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See detailCan Lignin Wastes Originating From Cellulosic Ethanol Biorefineries Act as Radical Scavenging Agents?
Vanderghem, Caroline ULg; Jacquet, Nicolas ULg; Richel, Aurore ULg

in Australian Journal of Chemistry (in press)

Lignin is a co-product from the biorefinery and paper industry. Its non-energetic valorization remains a field of extensive R&D developments. In this perspective, this study is undertaken to evaluate the ... [more ▼]

Lignin is a co-product from the biorefinery and paper industry. Its non-energetic valorization remains a field of extensive R&D developments. In this perspective, this study is undertaken to evaluate the radical scavenging ability of some herbaceous lignins. These lignins, extracted from Miscanthus (Miscanthus x giganteus) or Switchgrass (Panicum Virgatum L.), are selected as benchmarks for this study as a function of their chemical structure and average molecular weight. These technical lignins, side-products in the bioethanol production process, are found to display a moderate antioxidant activity as evaluated by the DPPH (1,1-diphenyl-2-picrylhydrazil) free radical scavenging test system. A correlation between the radical scavenging properties and the molecular features is proposed and discussed. Infrared spectroscopy is evaluated as a straightforward qualitative prediction tool for the radical scavenging capacity. [less ▲]

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See detailFractionation of apple by-products as source of new ingredients: Current situation and perspectives
Rabetafika, Holy-Nadia ULg; Bchir, Brahim; Blecker, Christophe ULg et al

in Trends in Food Science & Technology (in press)

Apple (Malus sp.) is among the most processed fruit that generates high amount of wastes. Depending on processes, various by-products are available offering a great diversity of low-cost raw materials ... [more ▼]

Apple (Malus sp.) is among the most processed fruit that generates high amount of wastes. Depending on processes, various by-products are available offering a great diversity of low-cost raw materials. Biorefinery processes are expected to convert them into new added-value products such as hemicelluloses, oligosaccharides and polyphenols. This paper reviews the current uses of apple by-products as source of fibre and phytochemicals with special emphasis on recent fractionation processes. Future trends and challenges of apple by-product reuse are discussed. [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 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 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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See detailINFLUENCE OF STEAM EXPLOSION ON THECRYSTALLINITY OF CELLULOSE FIBER
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2014, February 07)

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure cellulose fiber. When the severity factor is below 5.2, an increase of the overall crystallinity of the samples is observed with the treatment intensities. For higher intensities, a significant thermal degradation of cellulose lead to an important change in substrate composition, which lead to a further decrease of cellulose crystallinity. [less ▲]

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See detailOld inks: pigments extracted from plants
Despy, Jessica; Wymeersch, Noémie; Bouchat, Isabelle et al

in BOOK OF SHORT ABSTRACTS - POSTER PRESENTATIONS 19TH NATIONAL SYMPOSIUM ON APPLIED BIOLOGICAL SCIENCES (2014, February 07)

Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A ... [more ▼]

Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A significant example of this is the Cosquer cave (-19,000 to -27,000 years) located near Marseilles. Pigments and dyes can be classified into two broad categories and five families: natural pigments and dyes and those called artificial. The first one of these five families includes the mineral pigments. Among these we can find the clays (yellow ochre, red ochre, green clay, brown clay) and the stones like lapis lazuli (blue). The second and third families gather the organic dyes and pigments. Those that have vegetal origins like indigo (blue) and madder (red) compose the second family and those that have animal origins like cochineal (red) and kermes dyers (carmine) form the third family. One family includes pigments and dyes stemming from chemical reactions such as verdigris or red lead (family 4) and the other one is made of the miscellaneous inks such as iron-gall type who are vegetal and mineral one (family 5). All these pigments, although they have been used for centuries, have been replaced by synthetic dyes from the oil industry at the end of the 19th century. Indeed, they have the advantage of reproducibility of the properties unlike natural pigments. But the scarcity of oil causes a renewed interest in natural preparations. We report the extraction of pigments from plants. [less ▲]

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See detailPaints based on renewable materials
Olive, Gilles ULg; Richel, Aurore ULg

in BOOK OF SHORT ABSTRACTS - POSTER PRESENTATIONS 19TH NATIONAL SYMPOSIUM ON APPLIED BIOLOGICAL SCIENCES (2014, February 07)

Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming ... [more ▼]

Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming material, diluted in solvents. Pigments are solid particles, used to give opacity and/or color. Today almost all pigments have a synthetic origin. The fillers are often natural compounds. Unlike pigments, fillers have low opacity and are colorless. These very cheap products achieve the required solid content under satisfactory economic conditions. Resins used in paints have the property of forming a continuous solid (hard or flexible) film under specific conditions. They are often called “resins”. They can be solid or liquid at room temperature. The solvents are used to control the viscosity of the paint in order to facilitate its production and application. The solvents used are volatile compounds. Additives are minor compounds (a few percent), whose function is to either promote or prevent some developments of the product. For example, surfactants improve the homogeneity of the dispersion. Some additives protect the film against mold or ultraviolet radiation, or against the formation of free radicals under the action of sunlight. Since the end of the 18th century most of those paints are petroleum-based. But the near disappearance of the petroleum causes a renewed interest in bio-based preparations. In this communication, we present an overview of bio-based alternatives. [less ▲]

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See detailLes modèles économiques du bioraffinage en région wallonne : de l'exploration des débouchés et des niches de marché aux stratégies de développement industriel
Richel, Aurore ULg

Conference (2014, February)

1) Acteurs de la bio-économie en Wallonie 2 Transition vers le bioraffinage de seconde génération ? Les grandes questions et éléments de réponse (Flux de matières premières ?, Technologies de conversion ... [more ▼]

1) Acteurs de la bio-économie en Wallonie 2 Transition vers le bioraffinage de seconde génération ? Les grandes questions et éléments de réponse (Flux de matières premières ?, Technologies de conversion ? Produits cibles et marchés ? Positionnement des acteurs académiques et privés sur la chaine de valeur ? 3) Flux de matières premières en Wallonie – Carte d’occupation des sols, inventaire du potentiel en biomasse pour le bioraffinage de seconde génération (biomasse agricole, forestière, coproduits des industries de transformation food et non-food) 4) Quel(s) produit(s) et quel(s) marché(s) ? Liste des 10 molécules d’intérêt pour la Wallonie, molécules à haute valeur ajoutée et marchés de niche, cibles actuelles des recherches académiques et industrielles 5) Stratégie wallonne en termes de bioraffinage de seconde génération – quelques exemples d’initiatives R&D privées et publiques 6) Conclusions [less ▲]

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See detailWater soluble exo-polysaccharide from Syncephalastrum racemosum, a strong inducer of plant defence reactions
Valepyn, Emmanuel ULg; Cabrera, Juan-Carlos; Richel, Aurore ULg et al

in Carbohydrate Polymers (2014), 101

This study examines the production, characterization and bioactivity on plant cell cultured in vitro of exopolysaccharides (EPS) from Syncephalastrum racemosum CBS 443.59. Firstly, the influence of the ... [more ▼]

This study examines the production, characterization and bioactivity on plant cell cultured in vitro of exopolysaccharides (EPS) from Syncephalastrum racemosum CBS 443.59. Firstly, the influence of the fungus culture condition in shake flasks (pH, temperature and different carbon and nitrogen sources) on EPS and biomass production were evaluated. In order to enhance EPS production, a new protocol based on two-stage pH fermentation in a 3 L stirred fermentor was developed. Under this condition, EPS production increased by 3.55 times, compared to a constant pH process, reaching a maximal EPS concentration of 2.62 g/L. Structurally, the EPS contains a polyglucuronic acid backbone, linked essentially with mannose and fucose units and some galactose and glucose units. The bioactivity of EPS as inducer of defence reactions in plant suspension-cultured cells was also studied. Our results show, for first time, that EPS from S. racemosum CBS 443.59 induces, depending on the concentration, PAL activation and H2O2 synthesis in Arabidospsis thaliana cell suspensions. [less ▲]

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See detailLignin extraction from Mediterranean agro-wastes: Impact of pretreatment conditions on lignin chemical structure and thermal degradation behavior
Manara, Panagiota; Zabaniotou, Anastasia; Vanderghem, Caroline ULg et al

in Catalysis Today (2014), 223

Three different types of Mediterranean, agro-industrial wastes (olive kernels, grape pomace/seeds, peach kernels), were subjected to two pretreatment processes, a chemical/organosolv and a physicochemical ... [more ▼]

Three different types of Mediterranean, agro-industrial wastes (olive kernels, grape pomace/seeds, peach kernels), were subjected to two pretreatment processes, a chemical/organosolv and a physicochemical one. The organosolv process included lignocellulosic biomass treatment with formic acid/acetic acid/water (30/50/20, v/v%), for 3 h at 107 °C, while the physicochemical method was conducted by immersing the biomass in a water/ethanol (8/92, v/v%), H2SO4 0.32 M, solvent and further exposing the slurry to microwave irradiation (maximum 250 W) for 1/2 h at 150 °C. Both processes were evaluated regarding the achieved delignification and the purity of the extracted lignins. The effect of the pretreatment processes onto the structure and thermal decomposition behavior of the extracted lignins was investigated via FT-IR and TGA analysis, respectively. The objective of the research work was to investigate potential valorization routes for these biomass agro-residues in the context of a biorefinery, focusing on lignin extraction. The pretreatment results showed that the obtained lignins, derived from both procedures, were of high purity (>82 wt%). Under the organosolv procedure, peach kernel delignification showed the maximum value (∼16 wt%), while under microwave pretreatment, olive kernel delignification showed the maximum value (∼35 wt%). Grape pomace/seeds appeared to be the most resistant in both treatments. [less ▲]

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See detailOptimization of a formic/acetic acid delignification treatment on beech wood and its influence on the structural characteristics of the extracted lignins
Simon, Mathilde; Brostaux, Yves ULg; Vanderghem, Caroline ULg et al

in Journal of Chemical Technology & Biotechnology (2014), 89(1), 128-136

Background In order to replace petrochemicals by bio-based lignin products in a lot of high value-added applications, a formic/acetic acid treatment was adapted to beech wood (Fagus sylvatica L.) for ... [more ▼]

Background In order to replace petrochemicals by bio-based lignin products in a lot of high value-added applications, a formic/acetic acid treatment was adapted to beech wood (Fagus sylvatica L.) for lignin extraction. Results Beech wood particles were delignified at atmospheric pressure by a formic acid/acetic acid/water mixture. Cooking time and temperature were optimized for delignification, pulp yield and 2-furfural concentration. Response surface design analysis revealed that delignification yield increased with cooking time and temperature. Conclusion The multi-criteria optimization of delignification was used to find the ideal cooking conditions (5h07 min, 104.2°C) which could be satisfactory for the maximization of delignification (70.5%) and pulp yield (58.7%) and, to a lesser extent, for the minimization of 2-furfural production. Treatment conditions were found to influence the chemical structure of extracted lignins. Cooking time and temperature influenced inversely lignin molecular weights. [less ▲]

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