References of "Richel, Aurore"
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See detailMonitoring the laccase reaction of vanillin and poplar hydrolysate
Sòti, Valentin; Jacquet, Nicolas ULg; Apers, Sandra et al

in Journal of Chemical Technology & Biotechnology (in press)

BACKGROUND: Laccase is an intensively researched enzyme for industrial use. Except for decolorisation measurements, HPLC analysis is the conventional method for monitoring the phenolic removal during ... [more ▼]

BACKGROUND: Laccase is an intensively researched enzyme for industrial use. Except for decolorisation measurements, HPLC analysis is the conventional method for monitoring the phenolic removal during laccase enzyme reaction. This paper reports an investigation of the continuous UV absorbance follow-up of the laccase reaction with steam pretreated poplar hydrolysate. RESULTS: Vanillin was used as a model substrate and lignocellulose xylose rich fraction (XRF) as a biologically complex substrate for laccase detoxification. The reaction was followed by HPLC-UV as well as by UV spectrometric measurements. Results suggest that the reaction can be successfully monitored by measuring the change of UV absorbance at 280 nm, without previous compound separation. In case of XRF experiments the spectrophotometric follow-up is especially useful, as HPLC analysis takes a long time and provides less information than in case of single substrates. The method seems to be suitable for optimization and process control. CONCLUSION: The obtained results can help to construct a fast, easy and straightforward monitoring system for laccase-phenolic substrate reactions. [less ▲]

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See detailScalable temperature induced stress for the large-scale production of functionalized Bifidobacteria
Nguyen, Huu Thanh ULg; Razafindralambo, Hary; Richel, Aurore ULg et al

in Journal of Industrial Microbiology & Biotechnology (in press)

The application of sub-lethal stresses is known to be an efficient strategy to enhance survival of probiotic bacteria during drying processes. In this context, we previously showed that the application of ... [more ▼]

The application of sub-lethal stresses is known to be an efficient strategy to enhance survival of probiotic bacteria during drying processes. In this context, we previously showed that the application of heat stress upon the entry into stationary phase increased significantly the viability of Bifidobacterium bifidum. However, this heat shock has been considered only in small scale bioreactor and no information is available for a possible scaling-up strategy. Five different operating scales (0.2 L, 2 L, 20 L, 200 L and 2000 L) have thus been tested and the results showed that the viability of B. bifidum increases from 3.15 to 6.57 folds, depending on the scale considered. Our observations pointed out the fact that the heat stress procedure is scalable according to the main outcome, i.e. increases in cell viability, but other factors have to be taken into account. Among these factors, dissolved carbon dioxide seems to play a significant role since it explain the differences observed between the test performed at lab-scale and in industrial conditions. [less ▲]

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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 detailAlternatives to traditional valorisation ways for brewer’s spent grains
Villani, Nicolas ULg; Aguedo, Mario ULg; Richel, Aurore ULg

Poster (2015, August 05)

Brewer’s Spent Grains (BSG) are a highly available and cheap food supply chain waste (FSCW) that is mainly used in low-valued feed applications. This residue represents around 85 % of the total amount of ... [more ▼]

Brewer’s Spent Grains (BSG) are a highly available and cheap food supply chain waste (FSCW) that is mainly used in low-valued feed applications. This residue represents around 85 % of the total amount of waste produced by breweries with an annual tonnage of 3.4 million tons (on a dry basis) in the European Union. Based on its composition, BSG could be valorised in a wide variety of value-added products. For example, cellulose and remaining starch could easily be turned into ethanol or used as solid state fermentation media or as platform molecules for further chemical synthesis. These alternative valorisation ways could lead to an important economic relief through the whole brewery industry. Herein is described a multistep fractionation of BSG into cellulosic pulp, free sugars, proteins, germs and lignin using an Organosolv acidic pretreatment. This extraction procedure has been optimised in order to allow the most efficient and complete valorisation of BSG. [less ▲]

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See detailUrban biorefineries: a solution to manage and upgrade wastes in Wallonia ? Strategic aspects, proof-of-concept and industrial transfert
Richel, Aurore ULg

Scientific conference (2015, July)

“Urban biorefining” is an original concept aiming at using urban wastes (household wastes, municipal wastes, industrial liquid and/or solid residues and side-products, etc.), mainly of vegetal origin, for ... [more ▼]

“Urban biorefining” is an original concept aiming at using urban wastes (household wastes, municipal wastes, industrial liquid and/or solid residues and side-products, etc.), mainly of vegetal origin, for the production of an array of biofuels and bioproducts. This “urban biorefining” concept fits particularly with the economic, geographic and politic contexts and constraints of the Walloon Region (south part of Belgium). Indeed, Walloon Region is a very small territory (area of about 6,504 sq mi) with a temperate climate. Supply feedstock, mainly arising form forestry and agriculture, are thus rather restricted, submitted to importation, and subjected to non-standardized quality. Several examples of our regional strategy, still available on an industrial scale, are herein proposed and detailed. [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 detailComparative biochemical analysis after steam pretreatments of lignocellulosic biomass from six combined morphological parts of Williams Cavendish banana plant (Triploid Musa AAA group)
Kamdem, Irenée ULg; Jacquet, Nicolas ULg; Tiappi Deumaga, Mathias Florian ULg et al

in Waste Management & Research : The Journal of the International Solid Wastes & Public Cleansing Association (2015)

The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the ... [more ▼]

The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the results of a biochemical analysis performed on Williams Cavendish Lignocellulosic Biomass (WCLB) after steam cracking (SC) and steam explosion (SE) pretreatments. Solid (S) and liquid (L) fractions (Fs) obtained from SC pretreatment performed at 180°C (SLFSC180) and 210°C (SLFSC210) generated, after diluted acid hydrolysis, the highest proportions of neutral sugar (NS) contents, specifically 52.82±3.51 and 49.78±1.39 %w/w WCLB’s dry matter (DM), respectively. The highest proportions of glucose were found in SFSC210 (53.56±1.33 %w/w DM) and SFSC180 (44.47±0.00 %w/w DM), while the lowest was found in unpretreated WCLB (22.70±0.71 %w/w DM). Total NS content assessed in each LF immediately after SC and SE pretreatments was less than 2 %w/w of the LF’s DM, thus revealing minor acid autohydrolysis consequently leading to minor NS production during the steam pretreatment. WCLB subjected to SC at 210°C (SC210) generated up to 2.7-fold bioaccessible glucan and xylan. SC and SE pretreatments showed potential for the deconstruction of WCLB (delignification, depolymerisation, decrystallization and deacetylation), enhancing its enzymatic hydrolysis. The concentrations of enzymatic inhibitors such as 2-furfuraldehyde and 5-(hydroxymethyl)furfural from LFSC210 were the highest (41 and 21 µg mL-1, respectively). This study shows that steam pretreatments in general and SC210 in particular are required for efficient bioconversion of WCLB. Yet, biotransformation through biochemical processes (e.g., anaerobic digestion) must be performed to assess the efficiency of these pretreatments. [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 detailEt si nos déchets devenaient la source de nouveaux produits. Notion d'économie circulaire
Jacquet, Nicolas ULg; Istasse, Thibaut ULg; Berchem, Thomas ULg et al

Conference given outside the academic context (2015)

Notre objectif et nos recherches se concentrent sur l'utilisation des déchets agricoles et forestiers, les déchets végétaux et industriels et nos déchets ménagers pour produire une gamme de nouveaux ... [more ▼]

Notre objectif et nos recherches se concentrent sur l'utilisation des déchets agricoles et forestiers, les déchets végétaux et industriels et nos déchets ménagers pour produire une gamme de nouveaux produits, biocarburants ou molécules chimiques. [less ▲]

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

Scientific conference (2015, April 20)

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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 detailNon Digestible Oligosaccharides Modulate the Gut Microbiota to Control the Development of Leukemia and Associated Cachexia in Mice.
Bindels, Laure B.; Neyrinck, Audrey M.; Salazar, Nuria et al

in PloS one (2015), 10(6), 0131009

We tested the hypothesis that changing the gut microbiota using pectic oligosaccharides (POS) or inulin (INU) differently modulates the progression of leukemia and related metabolic disorders. Mice were ... [more ▼]

We tested the hypothesis that changing the gut microbiota using pectic oligosaccharides (POS) or inulin (INU) differently modulates the progression of leukemia and related metabolic disorders. Mice were transplanted with Bcr-Abl-transfected proB lymphocytes mimicking leukemia and received either POS or INU in their diet (5%) for 2 weeks. Combination of pyrosequencing, PCR-DGGE and qPCR analyses of the 16S rRNA gene revealed that POS decreased microbial diversity and richness of caecal microbiota whereas it increased Bifidobacterium spp., Roseburia spp. and Bacteroides spp. (affecting specifically B. dorei) to a higher extent than INU. INU supplementation increased the portal SCFA propionate and butyrate, and decreased cancer cell invasion in the liver. POS treatment did not affect hepatic cancer cell invasion, but was more efficient than INU to decrease the metabolic alterations. Indeed, POS better than INU delayed anorexia linked to cancer progression. In addition, POS treatment increased acetate in the caecal content, changed the fatty acid profile inside adipose tissue and counteracted the induction of markers controlling beta-oxidation, thereby hampering fat mass loss. Non digestible carbohydrates with prebiotic properties may constitute a new nutritional strategy to modulate gut microbiota with positive consequences on cancer progression and associated cachexia. [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 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 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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