References of "Richel, Aurore"
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See detailBiochemical characterization of the oil of durum wheat germ (Tunisian variety)
Kammoun, Maroua; Rassâa, Neila; Mejri-Gaïda, Myriam et al

in Journal of New Sciences (in press)

The wheat germ oil may constitute an alternative to the misuse of this cereal grain resource. The Tunisian exploitation is limited, at present, in the human and animal feed in the grain form, straw or ... [more ▼]

The wheat germ oil may constitute an alternative to the misuse of this cereal grain resource. The Tunisian exploitation is limited, at present, in the human and animal feed in the grain form, straw or some transformed products. For the purpose of characterization, the wheat germ oil has been extracted by Soxhlet apparatus from a Tunisian variety of durum wheat (Maali) based on the hexane as a solvent. An analysis by gas chromatography (GC) was then performed to identify and quantify the fatty acids of the oil. Then, the oil has submitted to a second chromatography analysis in liquid phase (HPLC) to quantify the tocopherols. The most important fatty acids constituting have been the two polyunsaturated acids linoleic acid C18:2 (OMEGA 6) and the gamma acid- linoleic C18:3 : 58.24 % and 4.19 % respectively; and the acid monounsaturated oleic acid C18:1 ( 24.49 %) but also some saturated acid: palmitic acid C16:0 with ( 19.50 % ), and the stearic acid C18:0 (1.29%). For this variety of Tunisian durum wheat, the wheat germ oil contains, in addition, 80.27 mg / 100g of α- tocopherols (vitamin E). The wheat germ oil extracted from the Tunisian variety 'Maali' has proved rich in vitamin E and omega-6 ; a better valorisation on the nutritional or pharmaceutical plan is to this title recommended. [less ▲]

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See detailMetabolic profile of mixed culture acidogenic fermentation of lignocellulosic residues and the effect of upstream substrate fractionation by steam explosion
Perimenis, Anastasios; van Aarle, Ingrid; Nicolay, Thomas et al

in Biomass Conversion and Biorefinery (in press)

Lignocellulosic biomass residues have attracted attention for the sustainable production of molecules for material and energetic use through biochemical conversion. Their recalcitrant structure prevents a ... [more ▼]

Lignocellulosic biomass residues have attracted attention for the sustainable production of molecules for material and energetic use through biochemical conversion. Their recalcitrant structure prevents a broader use and asks for the development of sustainable techniques that can efficiently separate, recover and valorize the constituting components. In a cascading concept, residual streams of such processes can be further exploited in an attempt to valorize the largest possible fraction of the initial material. Three lignocellulosic substrates, namely dried sugar beet pulp, wheat bran and miscanthus straw, were upstream fractionated by steam explosion to extract the hemicellulose fraction. This study evaluated the valorization of the residual solid fraction through mixed acidogenic fermentation for the production of volatile fatty acids (VFA) as platform chemicals. Batch experiments have been conducted for the reference material (non-treated) and the solid fraction remaining after steam explosion, with and without the addition of an external mixed inoculum. Steam explosion residues contained less hemicellulose than the initial materials. The difference in the fermentation profile between steam explosion residues and non-treated substrates is dependent on the substrate. Maximum total VFA (tVFA) concentration was 18.8 gCOD/kgmixed_liquor, and maximum yield of chemical oxygen demand (COD) conversion into tVFAwas 33 % for the case of non-treated inoculated beet pulp. [less ▲]

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See detailGenotype contribution to the chemical composition of banana rachis and implications for thermo/biochemical conversion
Tiappi Deumaga, Mathias Florian; Happi Emaga, Thomas; Tchokouassom, Raphael et al

in Biomass Conversion and Biorefinery (in press)

Chemical composition of banana rachis from three varieties (Grande naine, Pelipita, and CRBP969) was ana- lyzed, and the genotype contribution to composition variabil- ity was investigated. Wet chemistry ... [more ▼]

Chemical composition of banana rachis from three varieties (Grande naine, Pelipita, and CRBP969) was ana- lyzed, and the genotype contribution to composition variabil- ity was investigated. Wet chemistry and instrumental analysis procedures (X-ray diffraction, 31P NMR spectroscopy, and thermogravimetry) were used. Some significant differences were found among the three genotypes: GN-AAA genotype was found to be significantly the highest in ash fraction (30.16 %) and the lowest in acid insoluble lignin (6.58 %) at 95 % confidence level. It showed also the highest content in potassium (43.5 % in ash). Implication of compositional dif- ferences on valorization efficiency by biochemical or thermo- chemical pathways was investigated. For this purpose, corre- lation coefficients between compositional characteristics and yields in volatile compounds from pyrolysis and glucose yields from enzymatic saccharification were analyzed. Ash content was revealed to be the main drawback parameter for volatile yields from pyrolysis (r = −0.93), while for glucose yields during saccharification were limited mainly by the con- tent in guaiacyl units of the lignin fraction (r = −0.98). How- ever, a strong and positive correlation was established be- tween the volatiles yield and the acid insoluble lignin content (r = 0.98) Thus, according to these observations and based on their compositional significant differences, GN-AAA was the better candidate for bioconversion pathway while PPT-ABB and CRBP969-AAAB samples were shown to be better can- didates for thermochemical conversion pathway. This work gives important preliminary information for considering ba- nana rachis as an interesting feedstock candidate for biorefinery. [less ▲]

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See detailWood Acid Hydrolysate as a Feedstock for Chlorella Growth
Miazek, Krystian ULg; Goffin, Dorothée ULg; Richel, Aurore ULg et al

Scientific conference (2015, June 24)

In this work, the effect of beech (Fagus sylvatica) wood acid hydrolysate on growth of Chlorella sorokin-iana was evaluated. Experiments carried out in this study show that neutralized wood acid ... [more ▼]

In this work, the effect of beech (Fagus sylvatica) wood acid hydrolysate on growth of Chlorella sorokin-iana was evaluated. Experiments carried out in this study show that neutralized wood acid hydrolysate can vastly improve Chlorella growth, due to the presence of organic carbon. However, simultaneously the suppression of Chlorella growth at the onset of cultivation was observed, presumably due to inhibitory substances, and this effect was more pronounced with the increase of hydrolysate dosage. Beech wood acid hydrolysate can be a valuable feedstock to stimulate Chlorella growth, on condition that inhibitory level of hydrolysate loading is avoided. [less ▲]

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See detailEt si nos déchets devenaient de nouveaux produits: notion d'économie circulaire
Richel, Aurore ULg

Conference given outside the academic context (2015)

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See detailFood Compounds from Meadow Grasshoppers
Paul, Aman ULg; Frederich, Michel ULg; Uyttenbroeck, Roel ULg et al

Poster (2015, March 15)

Eating insects as food, particularly grasshopper is practiced in many cultures throughout the world. Meadow grasshopper (Chorthippus parallelus) is commonly found in Europe and some part of Asia. It is ... [more ▼]

Eating insects as food, particularly grasshopper is practiced in many cultures throughout the world. Meadow grasshopper (Chorthippus parallelus) is commonly found in Europe and some part of Asia. It is already known that grasshoppers of Chorthippus species are consumed as food in countries such as Thailand. With the aim of evaluating the nutritional potential of this insect species the proximate nutritional composition of grasshoppers caught from the local fields was realized. Besides this, the fatty acid profile of extracted lipids, amino acid profile and mineral composition of the insect was also revealed. Results suggest that meadow grasshopper is an excellent source of protein and essential amino acids. Lipids extracted from the grasshopper have an interesting fatty acid composition. Also the grasshopper contains some minerals that are important for body. With such protein content, amino acid profile, fatty acid profile of the lipids and mineral content this grasshopper species could present an interesting alternate to conventional protein sources. [less ▲]

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See detailCaractérisation physico-chimique et structurale de la poudre et des ulvanes de l'algue ulva lactuca
Guidara, Mariem; Yaich, Hela; Garna, Haikel et al

Poster (2015, March 15)

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See detailLes initiatives commerciales de bioraffinage en Région Wallonne: production de biocarburants et voies de valorisation connexes
Jacquet, Nicolas ULg; Desquay, Lucas ULg; Jadot, Bastien et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2015), 19(2), 197-203

Introduction Biorefining is progressively gaining interest in Wallonia as a complement to the conventional petrochemical industry. Biorefineries are categorized according to the nature of the raw ... [more ▼]

Introduction Biorefining is progressively gaining interest in Wallonia as a complement to the conventional petrochemical industry. Biorefineries are categorized according to the nature of the raw materials they treat (food or non-food) and the nature of their productions (energy and biofuels or biobased compounds). Literature Production of first-generation and second-generation biofuels (bioethanol and biodiesel) is described, as well as their parallel valorisation pathways. A description of the Belgian biobased industry is also provided. Conclusion Diversification of supply chains, as well as the need to promote a circular economy, becomes a priority for the development of biorefining in Wallonia. [less ▲]

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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 (2015), 73

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 detailApplication of Steam Explosion as Pretreatment on Lignocellulosic Material: A Review
Jacquet, Nicolas ULg; Maniet, Guillaume ULg; Vanderghem, Caroline ULg et al

in Industrial & Engineering Chemistry Research (2015), 54(10), 2593-2598

Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of lignocellulosic structural components by the action of heating, formation of organic acids during the process, and ... [more ▼]

Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of lignocellulosic structural components by the action of heating, formation of organic acids during the process, and shearing forces resulting in the expansion of the moisture. Two distinct stages compose the steam-explosion process: vapocracking and explosive decompression which include modification of the material components: hydrolysis of hemicellulosic components (mono- and oligosaccharides released), modification of the chemical structure of lignin, and modification of the cellulose crystallinity index, etc. These effects allow the opening of lignocellulosic structures and influence the enzymatic hydrolysis yield of the material. [less ▲]

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See detailMolécules issues de la valorisation de la lignine
Wertz, Jean-Luc; Richel, Aurore ULg; Gérin, Patrick

in ValBiom (2015), (Mars), 1-37

La valorisation de la lignine, dans le cadre de la bioraffinerie lignocellulosique du futur, est une thématique particulièrement prometteuse. En effet, la lignine est la principale matière première ... [more ▼]

La valorisation de la lignine, dans le cadre de la bioraffinerie lignocellulosique du futur, est une thématique particulièrement prometteuse. En effet, la lignine est la principale matière première renouvelable composée de motifs aromatiques. Ce polymère est le plus souvent valorisé uniquement par combustion dans les papeteries pour la production d’énergie. La mise en route de bioraffineries destinées à convertir la biomasse lignocellulosique en carburants de transport générera en général plus de lignine que nécessaire pour alimenter l’installation en énergie2. Dès lors, des efforts sont en cours pour transformer la lignine en produits à valeur ajoutée. Sa valorisation en composés aromatiques de bas poids moléculaires (tels que benzène, toluène, xylènes: BTX) permettrait une plus-value considérable dans la mesure où les BTX sont des molécules de base de la pétrochimie et représentent en 2015 un marché de 100 milliards de dollars3. On estime généralement que l’étude de la valorisation de la cellulose en particulier en éthanol a eu lieu il y a 20 ans, celle de la valorisation des hémicelluloses il y a 10 ans et celle de la valorisation de la lignine a lieu actuellement. [less ▲]

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See detailChemical composition and functional properties of dietary fibre extracted by Englyst and Prosky methods from the alga Ulva lactuca collected in Tunisia
Yaich, Hela; Garna, Haikel; Bchir, Brahim et al

in Algal Research (2015), 9

Nowadays there is a growing trend to find new sources of dietary fibre (DF), such as marine algae by-products that have traditionally been undervalued. In this respect, the aim of the present ... [more ▼]

Nowadays there is a growing trend to find new sources of dietary fibre (DF), such as marine algae by-products that have traditionally been undervalued. In this respect, the aim of the present investigation was firstly to compare two methods of dietary fibre quantification (Englyst and Prosky) and secondly to determine the chemical composition and some of the functional properties of total and insoluble fibres extracted in accordance with the Englyst method. The dietary fibres of dried Ulva lactuca collected from the Tunisian littoral were determined by the Prosky (gravimetric method) and Englyst (enzymatic-chemical method) methods. The two extraction methods (Englyst–Prosky) provided approximately the same values in total fibres (~54%). However, they had different insoluble and soluble fibre contents. U. lactuca contained 20.53% and 31.55% of soluble fibres and 34.37% and 21.54% of insoluble fibres using the Prosky and Englyst methods, respectively. The fractionation of the insoluble dietary fibre concentrate revealed that hemicellulose was the most abundant fraction (32.49%), followed by cellulose (16.59%) and “lignin-like” compounds (1.53%). For both fibre concentrates, the main neutral sugar was glucose (20.70%–27.59%), which corresponded to hemicellulose and cellulose. The water holding capacity of insoluble fibre concentrate was relatively high. It varied between 9.32 g and 10.3 g of water/g of dry fibre at 25 °C and 80 °C, respectively. Nevertheless, the oil holding capacity of the insoluble fibre concentrate was not affected by temperature. It was about 1.08 and 1.01 g of oil/g of dry fibre at 25 °C and 80 °C. Despite the significant functional properties of fibre concentrate, the presence of lead limits its use as an ingredient in the food industry. [less ▲]

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See detailOak barks as raw materials for the extraction of polyphenols for the chemical and pharmaceutical sectors: a regional case study
Dedrie, Maxime; Jacquet, Nicolas ULg; Bombeck, Pierre-Louis ULg et al

in Industrial Crops and Products (2015), 70

Despite their potential for chemical recycling, residues from forest harvesting and wood processing are mostly used for industrial applications with low added value (energy, paper pulp, panels). Bark of ... [more ▼]

Despite their potential for chemical recycling, residues from forest harvesting and wood processing are mostly used for industrial applications with low added value (energy, paper pulp, panels). Bark of both oak species, Quercus robur L. 1753, Quercus petraea (Matt.) Liebl. 1784 is a by-product from sawmill and pulp mill activities. Bark is mainly used as a fuel for the same wood plants. The aim of this study is to look at the feasibility of enhancing the value of this material through the extraction of bioactive molecules such as polyphenols (i.e. catechin, gallic and ellagic acids). First, the effect of industrial storage of logs and bark on their polyphenol content was explored. Then, referring to the selection of tan oaks in the past, the question of an optimum harvesting age is addressed in order to maximize the polyphenol content of the barks. In the end, molecular diversity of bark is examined through the identification of molecules of interest, using different chromatographic analyses. The results show an effect of the industrial context and an effect of the raw material age on the chemical properties of the bark. First investigations also highlight molecules of interest and the molecular diversity, which needs to be further explored. [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 (2015), 5(1), 115-124

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 detailUse of wheat bran arabinoxylans in chitosan-based films: Effect on physicochemical properties
Costa, Maria J.; Cerqueira, Miguel A.; Ruiz, Héctor A. et al

in Industrial Crops and Products (2015), 66

tThe aim of this work was to evaluate physicochemical properties of chitosan-based films with differentfractions of arabinoxylans (AXs). Five fractions composed by AXs or mixtures of AXs and arabino-xylo ... [more ▼]

tThe aim of this work was to evaluate physicochemical properties of chitosan-based films with differentfractions of arabinoxylans (AXs). Five fractions composed by AXs or mixtures of AXs and arabino-xylo-oligosaccharides (AXOS) obtained through three different processes were added to chitosan-based films.These films were obtained by solvent casting and characterized in terms of water vapor permeability(WVP), opacity, thickness, moisture content and mechanical properties (i.e., tensile strength – TS andelongation at break – EB), being the chemical interactions evaluated by FTIR.Moisture content values ranged between 20 and 30% for all five studied films being the lowest valueobserved for chitosan films with the fraction F1 of AX/AXOS (21.1%). The films with incorporation of F3a,F3b and F4 AXs fraction were more opaque (>10%) than the other studied films. Regarding mechanicalproperties CH films presented EB and TS values of 31.26% and 8.25 MPa, respectively, both these valuesremain statistically equal with the incorporation of AX/AXOS except for films containing the fractionF1 and F2. For films with the F2 fraction were obtained higher values of EB (41.31%) while for CH filmscontaining the F1 fraction the TS values (13.07 MPa) increased.In conclusion, wheat bran AXs can be successfully incorporated into chitosan-based edible films pro-viding, together with chitosan, an extra functional value to films, due their health benefits. [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, 1st generation 3) Biomass and biorefineries, second generation 4) 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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