References of "Gillet, Sébastien"
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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 detailBiochemical methane potential of residues of three banana varieties from Cameroon : fresh and dry peduncles
Awedem wobiwo, Florent; Happi Emaga, Thomas; Fokou, Elie et al

Poster (2015, January 30)

In Cameroon , the ratio of energy cost to standard of living for both electric and fuel energy is higher than in USA and EU. The local energy needs could be met by valorizing local wastes in an ... [more ▼]

In Cameroon , the ratio of energy cost to standard of living for both electric and fuel energy is higher than in USA and EU. The local energy needs could be met by valorizing local wastes in an environmentally and economically sustainable way. Banana and plantain plants produce significant quantities of post-harvest biomass wastes such as bulbs, pseudo stems, leaf sheaths, petioles–midribs, leaf blades, peduncles, rachis and blossoms which can be converted to methane-rich biogas by anaerobic digestion (AD). AD is a natural process of degradation of organic materials. [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 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 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 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 detailImpact of purification and fractionation process on the chemical structure and physical properties of locust bean gum
Gillet, Sébastien ULg; Blecker, Christophe ULg; Aguedo, Mario ULg et al

in Carbohydrate Polymers (2014)

Crude locust bean gum (CLBG) was purified and fractionated into two parts : the first was obtained by solubilization in water at 25 °C (GM25) and the second consisted in a further extraction at 80 °C on ... [more ▼]

Crude locust bean gum (CLBG) was purified and fractionated into two parts : the first was obtained by solubilization in water at 25 °C (GM25) and the second consisted in a further extraction at 80 °C on the residual impoverished fraction (GM80). The complete structural characterization has shown that GM80 possessed relatively longer chain lengths than GM25, a slightly lower degree of galactose substitution and a somewhat sharper galactosyl distribution in substituted and unsubstituted regions. A physical behavior analysis was carried out on solubilization kinetics, viscosity, viscoelasticity and formation of associated gels with xanthan or carrageenan. The average structure of GM80 generated larger intra-chain, inter-chain and inter-molecular interactions, resulting in the appearance of a stronger network. Small structural differences therefore generated very different physical behaviors. This study thus allowed to establish, in a precise and complete manner, fractionation-purification-structure-function relationships of galactomannans extracted from carob. [less ▲]

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See detailSynthese bibliographique de l'influence du procédé d'extraction et de purification sur les caractéristiques et les propriétés d'une gomme de caroube
Gillet, Sébastien ULg; Simon, mathilde; Paquot, Michel ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(1),

The carob tree is a species cultivated, in mediterranean countries, for its seeds. These seeds contain an endosperm rich in galactomannans used by the food industry for its texturing properties. After ... [more ▼]

The carob tree is a species cultivated, in mediterranean countries, for its seeds. These seeds contain an endosperm rich in galactomannans used by the food industry for its texturing properties. After harvesting, the seeds pass through a decutilation and a degermination. Cleaned endosperms are then milled to give crude locust bean gum. The purification step consists in a flour solubilization and then a precipitation of the galactomannans. Purification influences the characteristics of the resulting gum. The solubilization temperature is the parameter that affects the most on the final characteristics of the product. If it is hot or cold, galactomannans with different structural characteristics (and thus very different physical properties in aqueous solutions) will be selected. [less ▲]

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See detailImpact d'un fractionnement soustractif sur la relation structure-fonction de la gomme de caroube
Gillet, Sébastien ULg; Blecker, Christophe ULg; Aguedo, Mario ULg et al

Poster (2013, July 02)

Le choix d'une température de fractionnement de la gomme de caroube va conditionner les caractéristiques des fractions obtenues et par conséquent les potentialité d'applications de ces dernières.

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See detailLa chimie des saccharides
Gillet, Sébastien ULg; Paquot, Michel ULg

Learning material (2012)

Synthèse de chimie des sucres

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See detailL'analyse de sucres par HPEAC-PAD
Goffin, Dorothée ULg; Gillet, Sébastien ULg

Learning material (2011)

Présentation de l'analyse des sucres par Chromatographie Haute Performance Échangeuse d'Anions, couplée à un Détecteur par Ampérométrie Pulsée (HPAEC-PAD).

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See detailCHIMIE THÉORIQUE ET PHYSIQUE APPLIQUÉE À L’ANALYSE STRUCTURALE DES BIOMOLÉCULES (CG 204) - Exercices
Gillet, Sébastien ULg; Richel, Aurore ULg; Wathelet, Bernard ULg

Learning material (2011)

Le cours est axé sur l'apprentissage de l'analyse spectrale (IR, MS, RMN, RMN2D) des molécules organiques ou biologiques.L'interprétation qui en découle permettra d'en retrouver la structure.

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See detailTP de chimie biologique - 2ème partie
Gillet, Sébastien ULg; Paquot, Michel ULg

Learning material (2010)

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See detailMise en place d'un système de contrôle de gestion dans une entreprise du secteur des biotechnologies
Gillet, Sébastien ULg

Master's dissertation (2010)

L’entreprise XXX est une société anonyme active dans le secteur des biotechnologies. Elle est spécialisée dans la production de bactéries et la fabrication, à partir de celles-ci de différents mélanges ... [more ▼]

L’entreprise XXX est une société anonyme active dans le secteur des biotechnologies. Elle est spécialisée dans la production de bactéries et la fabrication, à partir de celles-ci de différents mélanges bactériens. Initialement, les produits de XXX étaient vendus à de nombreuses sociétés souhaitant contrôler précisément les processus microbiens impliqués dans leurs activités. A l’heure actuelle, une part majoritaire et croissante du chiffre d’affaire de l’entreprise est issue de la commercialisation de préparations « probiotiques », c'est-à-dire des mélanges de bactéries renforçant la flore intestinale et capables d’avoir une action bénéfique sur la santé humaine. La société XXX dispose d’un outil de comptabilité des coûts trop simpliste, induisant un système de contrôle de gestion qui n’est pas adapté. Consciente de ce fait, l’entreprise envisage la mise en place progressive d’un système de contrôle de gestion plus performant. La première étape d’une telle démarche est la révision complète de la comptabilité analytique. C’est précisément l’objectif que s’est fixé ce travail, en ayant recours à l’Activity Based Costing. En utilisant cette méthode, le coût de production des bactéries ainsi que celui des différents mélanges ont pu être déterminés. De ce fait, certains produits particulièrement peu rentables ont été mis en évidence. Le travail a également contribué à l’amélioration des connaissances sur les activités et processus menés dans l’entreprise, ainsi que leurs consommations en ressources. Les activités particulièrement coûteuses ont donc été identifiées, permettant à XXX, d’envisager en connaissance de cause des décisions de type « make or buy ». Enfin, des actions à mener pour affiner la précision des différents prix de revient ont été recommandées. [less ▲]

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See detailDevelopment of an original approach to evaluate effects of surfactants, biomass and pollutants on the scaling-up of a two-phase partitioning bioreactor
Aldric, Jean-Marc ULg; Gillet, Sébastien ULg; Delvigne, Frank ULg et al

in Journal of Chemical Technology & Biotechnology (2010), 84

BACKGROUND: Two-phase partitioning bioreactors (TPPBs) are considered as a new technology for xenobiotic degradation in gaseous effluents. However, there is still a need for more knowledge on how to ... [more ▼]

BACKGROUND: Two-phase partitioning bioreactors (TPPBs) are considered as a new technology for xenobiotic degradation in gaseous effluents. However, there is still a need for more knowledge on how to design and scale-up TPPBs. The partitioning of the two phases remains a misunderstood way of research. In particular, the impact of pollutant (isopropylbenzene), biomass and surfactant extract needs to be better evaluated. RESULTS:. An adaptated scale-down apparatus has been developed in order to quantify the speed of phase partitioning (SPP) into a plug flow section. Firstly, it was shown that isopropylbenzene (IPB) doesn’t destabilize more significantly the system. Secondly, respectively 0.5 g.L-1 and 0.05 g.L-1 of biomass and surfactant extract, separately or in mixture, were sufficient to ensure the stability of the two-phase system. Finally, a 100 m3 limit of scaling-up was suggested on the basis of the circulation time comparison. CONCLUSION: The scaling-up of an aqueous/silicone-oil TPPB was found to be definitely conceivable when the presence of biotic compounds were considered. However, further considerations are needed to verify our assumptions, in particular by taking into account the velocity field pattern in full-scale bioreactors and reproduce it in lab-scale apparatus. [less ▲]

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See detailTraitement ou recyclage... Les réacteurs biphasiques au service du traitement de l'air
Gillet, Sébastien ULg

in Journal des Ingénieurs (Le) (2009), 126(Décembre), 15-19

Ces dernières années, la pollution de l’air est devenue une préoccupation pour ses impacts environnementaux et sur la santé. Les réglementations contrôlant les émissions d’air pollué se sont d’ailleurs ... [more ▼]

Ces dernières années, la pollution de l’air est devenue une préoccupation pour ses impacts environnementaux et sur la santé. Les réglementations contrôlant les émissions d’air pollué se sont d’ailleurs multipliées. Face à ces problèmes, des solutions de traitement ont été développées, certaines utilisant même les potentialités des microorganismes pour épurer les effluents industriels. Les limites de ces traitements biologiques classiques sont même en voie d’être repoussées par une nouvelle génération de systèmes : les réacteurs biphasiques. [less ▲]

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See detailEffect of surfactants and biomass on the gas/liquid mass transfer in an aqueous-silicone oil two-phase partitioning bioreactor using Rhodococcus erythropolis T902.1 to remove VOCs from gaseous effluents
Aldric, Jean-Marc ULg; Gillet, Sébastien ULg; Delvigne, Frank ULg et al

in Journal of Chemical Technology & Biotechnology (2009), 84

BACKGROUND: The two-phase partitioning bioreactor (TPPB) has become a new strategy in the context of waste gas treatment. However, the impact of biomass and surfactants on gas/liquid (G/L) mass transfer ... [more ▼]

BACKGROUND: The two-phase partitioning bioreactor (TPPB) has become a new strategy in the context of waste gas treatment. However, the impact of biomass and surfactants on gas/liquid (G/L) mass transfer needs to be better evaluated because the impact of these factors on the mass transfer coefficient “ ” and the interfacial area “ ”, respectively, remains misunderstood. RESULTS: Our study showed that, firstly, the surfactant extract produced by Rhodococcus erythropolis reduced the surface hydrophobicity of the biomass. Secondly, an optimal concentration appeared to exist for both of the components, respectively 0.5 g.L-1 and 0.7 g.L-1 for biomass (B) and surfactant extract (SE) when the global mass transfer coefficient ( ) of oxygen was measured in a silicone oil/water TPPB. However, the combination of B and SE was found to induce a negative synergism. In particular, SE improved the interfacial area “ ” by increasing the bubble diameter, while B reduced it as soon as a concentration of 1g.L-1 was exceeded. By contrast, the SE acted negatively on the , while B improved it overall. CONCLUSION: Better consideration is needed of the effect of biotic components in order to understand the phenomenon of G/L mass transfer in a TPPB. The behaviour of biomass growth and surfactants may strongly influence the mathematical models suggested in the literature. [less ▲]

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