References of "Vandenbol, Micheline"
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See detailFunctional suppression of the yeast msb3- mutation
Biver, Sophie ULg; Vandenbol, Micheline ULg

Poster (2010, September)

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See detailFungal gene expression in a forest soil
Kellner, Harald ULg; Portetelle, Daniel ULg; Vandenbol, Micheline ULg

Poster (2010, August)

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See detailCaractérisation de la diversité des organismes symbiotiques et des activités glycosyl hydrolases dans le tube digestif de Reticulitermes santonensis (Feytaud) par une approche multidisciplinaire
Bauwens, Julien ULg; Matteotti, Christel ULg; Brognaux, Alison ULg et al

Scientific conference (2010, July 08)

Le bioéthanol cellulosique pourrait être une solution pour satisfaire le besoin croissant en énergie renouvelable. Actuellement, l’efficience de la transformation de la cellulose en sucres fermentescibles ... [more ▼]

Le bioéthanol cellulosique pourrait être une solution pour satisfaire le besoin croissant en énergie renouvelable. Actuellement, l’efficience de la transformation de la cellulose en sucres fermentescibles reste le principal facteur limitant. La recherche de nouvelles glycosyl hydrolases constitue une voie potentielle d’amélioration de la valorisation des composés ligno-cellulosiques. Trois types de glycosyl hydrolases sont généralement produites par les organismes capables d’utiliser efficacement ces composés : les endoglucanases, les exoglucanases/cellobiohydrolases, et les β-glucosidases. Dans les processus de digestion de la cellulose par les animaux, des organismes symbiotiques tels que des bactéries, des protistes et/ou des champignons sont fréquemment observés. Ces organismes contribuent en grande partie voir totalement à la production des complexes enzymatiques nécessaires. Chez les termites inférieures, comme notre modèle Reticulitermes santonensis (Feytaud), des protistes et des bactéries sont impliqués dans un système symbiotique complexe. Une étude multidisciplinaire est menée afin d’approfondir les rôles respectifs des différents groupes de symbiontes, via des approches « omiques », à savoir la protéomique (ESI-LC-MS-MS, 2D-SDS-PAGE couplée avec une analyse en spectrométrie de masse du type MALDI-TOF pour l’identification des protéines), la génomique (avec une approche métagénomique basée sur la construction d’une large banque de cDNA), la métabolomique (caractérisation des produits de dégradation de carbohydrates via une strategie LC-MS). De plus, l’isolation de microorganismes a également été employée dans la caractérisation de la diversité et de l’activité des glycosyl hydrolases chez R. santonensis. [less ▲]

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See detailFungi Unearthed: Transcripts Encoding Lignocellulolytic and Chitinolytic Enzymes in Forest Soil
Kellner, Harald ULg; Zak, Don; Vandenbol, Micheline ULg

in PLoS ONE (2010), 5(Issue 6), 10971-7

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See detailComplementation of Saccharomyces cerevisiae mutants using a soil metatranscriptomic library
Kellner, Harald ULg; Luis, Patricia; Portetelle, Daniel ULg et al

Poster (2010, May 21)

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See detailIntegrated “omics” approaches to investigate the chemical aspects of symbiosis in termites and potential application in ligno-cellulosic use.
Bauwens, Julien ULg; Matteotti, Christel ULg; Brognaux, Alison ULg et al

Scientific conference (2010, May 05)

Cellulosic bioethanol could be one of the solutions to satisfy the increasing demand in renewable energy. The most limitative problem is the efficiency of cellulose transformation into fermentable sugars ... [more ▼]

Cellulosic bioethanol could be one of the solutions to satisfy the increasing demand in renewable energy. The most limitative problem is the efficiency of cellulose transformation into fermentable sugars. Investigations to select new glycosyl hydrolases are an interesting approach that constitutes a potential opportunity to improve the valorization of lignocellulosic materials. Three major types of glycosyl hydolases are generally produced by organism’s that are able to efficiently use cellulosic compounds: the endoglucanases, the exoglucanases/cellobiohydrolases and the β-glucosidases. In the ability to transform lignocellulosic materials by animals, symbioses are generally observed with a range of micro-organisms including bacteria, protists and/or fungi that largely (or completely) contribute to the production of the needed enzymatic complexes. In termites, such active enzymes are produced in the insect digestive tract, by the termite insect itself or by symbiotic organisms. Within lower termites gut, such as in our model Reticulitermes santonensis (Feytaud), protists and bacteria are associated and involved in a complex symbiotic system. To investigate the respective role of the insect and different groups of symbionts, multidisciplinary “omics” approaches were here developed including proteomics (ESI-LC-MS-MS, 2D-Dige gel coupled with MALDI-TOF mass spectrometry for protein identification), genomics (with a metagenomic approach based on large cDNA bank construction), metabolomics (LC-MS stragety for carbohydrate degradation product characterization). Moreover, microorganism isolation was used to investigate and characterize glycosyl hydrolases diversity and activity in R. santonensis. The integration of this broad range of “omics” techniques allowed characterizing the role of symbionts in insects in a fundamental approach and to invtigate the chemical ecology of xylophagous insects but also corresponding to an efficient way to promote the selection of efficient enzymatic activities to potentially produce biofuels based on the use of existing lignocellulosic materials. [less ▲]

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See detailPlasmid-associated bacteriocin production by Lactobacillus LMG21688 Listeria monocytogenes growth rebound in a food system.
Kouakou, P.; Dortu, C.; Dubois Dauphin, Robin ULg et al

in FEMS Microbiology Letters (2010), 306(1), 37-44

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See detailStudy of thermomyces ianuginosa lipase in the presence of tributyrylglycerol and water
Santini, Sébastien; Crowet, Jean-Marc ULg; Thomas, Annick ULg et al

in Biophysical Journal (2009), 96(12), 4814-4825

The Thermomyces lanuginosa lipase has been extensively studied in industrial and biotechnological research because of its potential for triacylglycerol transformation. This protein is known to catalyze ... [more ▼]

The Thermomyces lanuginosa lipase has been extensively studied in industrial and biotechnological research because of its potential for triacylglycerol transformation. This protein is known to catalyze both hydrolysis at high water contents and transesterification in quasi-anhydrous conditions. Here, we investigated the Thermomyces lanuginosa lipase structure in solution in the presence of a tributyrin aggregate using 30 ns molecular-dynamics simulations. The water content of the active-site groove was modified between the runs to focus on the protein-water molecule interactions and their implications for protein structure and protein-lipid interactions. The simulations confirmed the high plasticity of the lid fragment and showed that lipid molecules also bind to a secondary pocket beside the lid. Together, these results strongly suggest that the lid plays a role in the anchoring of the protein to the aggregate. The simulations also revealed the existence of a polar channel that connects the active-site groove to the outside solvent. At the inner extremity of this channel, a tyrosine makes hydrogen bonds with residues interacting with the catalytic triad. This system could function as a pipe (polar channel) controlled by a valve (the tyrosine) that could regulate the water content of the active site. [less ▲]

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See detailInteresterification of rapeseed oil with anhydrous milk fat and its stearin fraction. II. Modifications of melting properties
Giet, Jean-Michel ULg; Aguedo, Mario ULg; Hanon, Emilien ULg et al

in GCIRC Bulletin (2009), 25

Chemical and/or physical modification of oils and fats are commonly used by food industry to widen their range of applications (1,2). Lipase-catalysed interesterification of anhydrous milk fat (AMF) and ... [more ▼]

Chemical and/or physical modification of oils and fats are commonly used by food industry to widen their range of applications (1,2). Lipase-catalysed interesterification of anhydrous milk fat (AMF) and various vegetable oils is now a well documented procedure (3-7). The purpose of this technique is to produce original structured fats with properties different from a simple blending, that may be used as spreads or introduced into pastry. The new fats contain higher amounts of polyunsaturated fatty acids (PUFA) than butter, which provides health benefits (8,9). To our knowledge only a few authors associated AMF fractionation with blending and interesterification (10,11), although this combination may be used to increase the ratio of vegetable oil in blends and thus the PUFA content of the product. The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In the present and second part are reported the resulting changes in physical properties, especially the melting behaviour through solid fat content (SFC), dropping point (DP) and fusion profiles by differential scanning calorimetry (DSC). [less ▲]

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See detailIntersterification of rapessed oil with anhydrous milk fat and its stearin fraction. I. Modifications of composition
Aguedo, Mario ULg; Giet, Jean-Michel ULg; Hanon, Emilien ULg et al

in GCIRC Bulletin (2009), 25

Milk fat in human diet is associated with cardiovascular diseases due to its high content in saturated fatty acids and cholesterol. Most vegetable oils are much healthier as they are rich in unsaturated ... [more ▼]

Milk fat in human diet is associated with cardiovascular diseases due to its high content in saturated fatty acids and cholesterol. Most vegetable oils are much healthier as they are rich in unsaturated fatty acids (1,2). Lipase-catalysed interesterification of oils and fats has arisen as an alternative to hydrogenation or chemical processes to produce margarine and shortenings (3), notably because they do not give rise to undesirable trans fatty acids (4). The enzyme exchanges fatty acids from one triglyceride to another, resulting in a redistribution of fatty acids species. For such a reaction, the lipase of Thermomyces lanuginosa was shown to be an efficient tool in solvent-free fat blends batches and micro-aqueous conditions (5). Enzymatic interesterification can thus be used to enrich “hard” fats with unsaturated fatty acids (6,7). As an illustration, rapeseed oil (RO) (a choice source of unsaturation-rich residues) was used in the present study to enrich anhydrous milk fat (AMF) with unsaturated C18 fatty acids (FA) (oleic, linoleic and linolenic acids). Comparatively, one “harder” fraction of AMF underwent the same reaction. The physico-chemical properties modifications induced by the reaction were followed. The compositional changes are reported in this first part and the consequent physical modifications are presented in a second part. [less ▲]

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See detailEnzymatic interesterification of anhydrous milk fat with rapeseed and/or linseed oil: oxidative stability
Giet, Jean-Michel ULg; Aguedo, Mario ULg; Danthine, Sabine ULg et al

in Journal of Agricultural and Food Chemistry (2009), 57(15), 6787-6794

Blends of anhydrous milkfat (AMF) and linseed oil (70/30), and AMF, rapeseed oil (RO) and linseed oil (LO), 70/20/10, were submitted to enzymatic interesterification. The oxidative stability of the blends ... [more ▼]

Blends of anhydrous milkfat (AMF) and linseed oil (70/30), and AMF, rapeseed oil (RO) and linseed oil (LO), 70/20/10, were submitted to enzymatic interesterification. The oxidative stability of the blends, the interesterified (IE) blends and IE blends with 50 ppm -tocopherol added as antioxidant were studied. Samples were stored in open flasks at 60°C, 25°C and 4°C, and periodically submitted to peroxide, p-anisidine, TBA value determination and UV measurement at 232 and 268 nm. The analysis of volatile compounds was carried out by SPME for the samples stored at 60°C. Peroxides appeared to be the only significant oxidation products after 12 weeks storage at 4°C. As expected, the binary blends (BB) were more sensitive to oxidation than the ternary blends (TB). The BB were associated with increased volatile emission compared to TB. Interesterification led to variable effects on the oxidation of fat mixtures, depending on composition and temperature (beneficial effect on BB, at both 25°C and 60°C, and a rather neutral effect on TB). The IE blends exhibited higher volatile release prior to ageing. A pro-oxidant effect of -tocopherol addition was observed at 25°C on both BB and TB. At 60°C, an antioxidant effect was observed on TB. [less ▲]

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See detailInteresterification of rapeseed oil with anhydrous milk fat and its stearin fraction
Aguedo, Mario ULg; Giet, Jean-Michel ULg; Hanon, Emilien ULg et al

Poster (2009)

Rapeseed oil (RO) (a choice source of unsaturation-rich residues) was used in the present study to enrich anhydrous milk fat (AMF) with unsaturated C18 fatty acids (FA) (oleic, linoleic and linolenic ... [more ▼]

Rapeseed oil (RO) (a choice source of unsaturation-rich residues) was used in the present study to enrich anhydrous milk fat (AMF) with unsaturated C18 fatty acids (FA) (oleic, linoleic and linolenic acids). Comparatively, one “harder” fraction of AMF underwent the same reaction. The physico-chemical properties modifications induced by the reaction were followed. The compositional changes are reported in this first part and the consequent physical modifications are presented in a second part. [less ▲]

Detailed reference viewed: 44 (18 ULg)
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See detailInteresterification of rapeseed oil with anhydrous milk fat and its stearin fraction
Giet, Jean-Michel ULg; Aguedo, Mario ULg; Hanon, Emilien ULg et al

Poster (2009)

The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In ... [more ▼]

The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In the present and second part are reported the resulting changes in physical properties, especially the melting behaviour through solid fat content (SFC), dropping point (DP) and fusion profiles by differential scanning calorimetry (DSC). [less ▲]

Detailed reference viewed: 66 (16 ULg)