References of "Thonart, Philippe"
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See detailPhysical and physiological impacts of different foam control strategies during a process involving hydrophobic substrate for the lipase production by Yarrowia lipolytica
Kar, Tambi ULg; Destain, Jacqueline ULg; Thonart, Philippe ULg et al

in Bioprocess and Biosystems Engineering (2012), 35(4), 483-492

The potentialities for the intensification of the process of lipase production by the yeast Yarrowia lipolytica on a renewable hydrophobic substrate (methyloleate) have been investigated. The key factor ... [more ▼]

The potentialities for the intensification of the process of lipase production by the yeast Yarrowia lipolytica on a renewable hydrophobic substrate (methyloleate) have been investigated. The key factor governing the lipase yield is the intensification of the oxygen transfer rate, considering the fact that Y. lipolytica is a strict aerobe. However, considering the nature of the substrate and the capacity for protein excretion and biosurfactant production of Y. lipolytica, intensification of oxygen transfer rate is accompanied by an excessive formation of foam. Two different foam control strategies have thus been implemented: a classical chemical foam control strategy (CFM) and a mechanical foam control (MFM) based on the Stirring As Foam Disruption (SAFD) principle. The second strategy allows foam control without any modifications of the physico-chemical properties of the broth. However, the MFM system design induced the formation of a persistent foam layer in the bioreactor. This phenomenon has led to the segregation of microbial cells between the foam phase and the liquid phase in the case of the bioreactors operated with MFM control, and induced a reduction at the level of the lipase yield. More interestingly, flow cytometry experiments have shown that residence time of microbial cells in the foam phase tends to induce a dimorphic transition which could potentially explain the reduction of lipase excretion. [less ▲]

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See detailMicrosale interactions between earthworms and microorganisms, a review
Zirbes, Lara ULg; Thonart, Philippe ULg; Haubruge, Eric ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(1), 125-131

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See detailPotentiality of using microbial biosensors for the detection of substrate heterogeneities and the assessment of microbial viability in industrial bioreactors: a complete set of experiments in chemostat and scale-down reactors, and elaboration of a mini scale-down platform
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

in Communications in Agricultural and Applied Biological Sciences (2012), 77(1), 3-7

Substrate limitation responsive biosensors have been used in order to detect spatial substrate heterogeneities, , inside industrial bioreactors (whole-cell biosensor). Three green fluorescent protein (GFP ... [more ▼]

Substrate limitation responsive biosensors have been used in order to detect spatial substrate heterogeneities, , inside industrial bioreactors (whole-cell biosensor). Three green fluorescent protein (GFP) transcriptional reporters have been chosen in E.coli, i.e. uspA::gfp, csiE::gfp and yciG::gfp. The promoter uspA is induced in response to a variety of stresses whereas the two other promoters, csiE and yciG, are supposed to be more specific in front of a substrate limitation. The responsiveness of these biosensors has been assessed in chemostat reactor. Secondly, the same biosensors have been tested in well-mixed laboratory reactors and in scale-down reactors able to reproduce industrial conditions. Finally, a mini scale-down platform has been proposed as a high throughput tool to investigate rapidly the usefulness of a given microbial biosensor. Local heterogeneities in mini-bioreactor have caused a decrease of GFP expression, as in scale-down reactor. The presence of GFP in supernatants was noticed and this leakage seems to be correlated with the membrane permeability. [less ▲]

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See detailIsolation and identification of a new Bacillus strain for amylase production
Bakri, Y.; Ammouneh, H.; El-Khouri, S. et al

in Research in Biotechnology (2012), 3(6), 51-58

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See detailScaphandre La science rencontre l'art: L'art
Haubruge, Eric ULg; Bay, Daniel ULg; Semal, Jean et al

in Haubruge, Eric; Bay, Daniel; Semal, Jean (Eds.) Scaphandre La science rencontre l'art (2012)

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See detailEffect of humic substances on in vitro rooting and acclimatization of Alder (Alnus glutinosa (L.) Gaertn).
Tahiri, Abdelghani ULg; Destain, Jacqueline ULg; Druart, Philippe et al

Poster (2012)

Humic substances (HS) are organic compounds resulting from the physical, chemical and microbiological transformations of organic residues. Present every where in the nature; they are taking part in basic ... [more ▼]

Humic substances (HS) are organic compounds resulting from the physical, chemical and microbiological transformations of organic residues. Present every where in the nature; they are taking part in basic functionalities in any ecosystems involving soils, sediments, waterand landfills. They are heterogeneous and complex carbon macromolecules. Our study aims to compare the effect of HS on in vitro rooting and acclimatization of the Alder species (Alnus glutinosa (L.) Gaertn) as tree growing on river banks or wasted areas. [less ▲]

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See detailPreliminary results on growing tree roots in vitro in presence of humic substances
Tahiri, Abdelghani ULg; Destain, Jacqueline ULg; Druart, Philippe et al

Poster (2012)

Humic substances (HS) are organic compounds resulting from the physical, chemical and microbiological transformations of organic residues. Present everywhere in the nature; they are taking part in basic ... [more ▼]

Humic substances (HS) are organic compounds resulting from the physical, chemical and microbiological transformations of organic residues. Present everywhere in the nature; they are taking part in basic functionalities in any ecosystems involving soils, sediments, water and landfills. They are heterogeneous and complex carbon macromolecules. Our study aims to determine the main biological properties of HS on plant growth in relation to their physicochemical properties. [less ▲]

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See detailLes entérocoques : avantages et inconvénients en biotechnologie (synthèse bibliographique)
Aguilar Galvez, A.; Dubois Dauphin, Robin ULg; Destain, Jacqueline ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(1), 67-76

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See detailNewly discovered natural functions for cyclic lipopeptides from rhizobacteria
Ongena, Marc ULg; Henry, G.; Deleu, Magali ULg et al

Conference (2012)

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See detailModulation of the lipopeptide pattern secreted by Bacillus subtilis upon colonization of different plant roots
Ongena, Marc ULg; Cawoy, Hélène ULg; Smargiassi, Maïté et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2012), 78

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See detailImpact of mixing imperfections on yeast bioreactor performances: Scale-down reactor concept and related experimental tools
Delvigne, Frank ULg; Blaise, Yannick ULg; Destain, Jacqueline ULg et al

in Cerevisia and Biotechnology (2012), 37

A method combining environmental data extracted from the dissolved oxygen profile of a fed-batch bioreactor and a dynamic discrete Markov chain model has been presented in order to give more insight about ... [more ▼]

A method combining environmental data extracted from the dissolved oxygen profile of a fed-batch bioreactor and a dynamic discrete Markov chain model has been presented in order to give more insight about the glucose and dissolved oxygen fluctuations experienced by the microorganisms during cultivation in heterogeneous bioreactor. The fed-batch cultivation of Saccharomyces cerevisiae has been performed in a well-mixed and a partitioned scale-down reactor (SDR). The analysis of the environmental sequences has shown extended time lengths for the glucose availability and depletion sequences in the case of the SDR under a DO-controlled fed-batch culture. The Markov chain model developed in this work is able to capture the stochastic environmental events, i.e. in our case the environmental states experienced by the microorganisms crossing the tubular part of the SDR. The simulation results show clearly an extension of the starvation periods in the case of the culture performed in the SDR. The simulations have been performed at the single cells level allowing future improvements of our model and notably in the context of the population segregation phenomena occurring in fed-batch cultures. As a perspective, flow cytometry has been presented as a high-throughput analytical tool for the investigation of yeast physiology at the single cell level and in process-related conditions. [less ▲]

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See detailPAMPs, MAMPs, DAMPs and others: An update on the diversity of plant immunity elicitors [PAMPs, MAMPs, DAMPs et autres: Mise à jour de la diversité des éliciteurs de l'immunité des plantes]
Henry, Guillaume; Thonart, Philippe ULg; Ongena, Marc ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(2), 257-268

Plants possess a broad array of defenses that could be actively expressed in response of pathogenic organisms or parasites but also following beneficial saprophytic microorganisms recognition ... [more ▼]

Plants possess a broad array of defenses that could be actively expressed in response of pathogenic organisms or parasites but also following beneficial saprophytic microorganisms recognition. Specifically, there are compounds derived from these organisms and called elicitors that are perceived by the plant to induce a locally or systemically expressed resistance. The understanding of the physiological and biological basis of these induced immunity mechanisms have greatly advanced over the past years but a deeper investigation of the mechanisms underlying the perception of elicitors is essential to develop novel strategies for pest control. The application of chemical and biological stimulators of plant immune defenses in conventional agriculture is expected to increase within the next years. Because of their organic origin and as they provide means for conferring plant protection in a non-transgenic manner, elicitors of plant immunity have a huge potential as biocontrol products. Through this review, we want to illustrate the diversity of compounds identified as stimulators of the plant immune system and describe the mechanisms by which they could be recognized at the plasma membrane level. [less ▲]

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See detailCOMPARISON BETWEEN CONTINUOUS AND BATCH PROCESSING TO PRODUCE XYLANASE BY Penicillium canescens 10-10c
Bakri, Y.; Akeed, Y.; Thonart, Philippe ULg

in Brazilian Journal of Chemical Engineering (2012), 29(3), 441-447

Penicillium canescens 10-10c strain was cultivated on barley straw hydrolysate as a soluble nutrient source and as inducer for xylanase production. Barley straw hydrolysate was obtained by treatment of ... [more ▼]

Penicillium canescens 10-10c strain was cultivated on barley straw hydrolysate as a soluble nutrient source and as inducer for xylanase production. Barley straw hydrolysate was obtained by treatment of barley straw with NaOH or hot water. In shake flask cultures, NaOH treatment was found to increase the biomass production, but was not accompanied by an increase in xylanase production. The best xylanase production (54 U/ml) was observed on hydrolyzed extract from barley straw treated with hot water (100 ºC) for 3 hours. Enzyme production was further improved by scaling up the cultivation process to a 3-L stirred tank bioreactor. For batch cultivations in the bioreactor, the maximum xylanase productivity reached 1.31 and 0.46 U/ml/h, respectively, after 96 and 168 hours of cultivation. However, xylanase productivity reached 3.46 U/ml/h in the continuous culture. These results suggest that xylanase can be produced efficiently by Penicillium canescens 10-10c in continuous culture from an inexpensive source such as barley straw hydrolysate. [less ▲]

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See detailLa production de biohydrogène à partir de substrats carbohydratés : état de l'art
Hiligsmann, Serge ULg; Beckers, Laurent ULg; Masset, Julien ULg et al

in Récents progrès en génie des procédés (2011, December 01)

Hydrogen is being considered as an ideal and clean energy carrier. The recent advances to produce biohydrogen from renewable sources such as biomass and particularly by fermentation of carbohydrate-rich ... [more ▼]

Hydrogen is being considered as an ideal and clean energy carrier. The recent advances to produce biohydrogen from renewable sources such as biomass and particularly by fermentation of carbohydrate-rich substrates from agriculture and agro-industries appear promising. Such a process enables both organic waste treatment and renewable energy production to be coupled. The paper presents the state of the art about the different hydrogen-producing microorganisms and the parameters that have been investigated in order to improve the hydrogen production yields and rates. [less ▲]

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See detailEffets de la pression partielle en hydrogène sur la production anaérobie de bioH2 par une bactérie chimiotrophe du genre Clostridium dans un nouveau réacteur à cylindre horizontal rotatif.
Beckers, Laurent ULg; Hiligsmann, Serge ULg; Hamilton, Christopher ULg et al

in Récents Progrès en Génie des Procédés (2011, December), 101

Hydrogen is widely considered as the most promising energetic carrier. At an industrial scale, steam reforming of methane is currently the major hydrogen producing process. But it may also be produced ... [more ▼]

Hydrogen is widely considered as the most promising energetic carrier. At an industrial scale, steam reforming of methane is currently the major hydrogen producing process. But it may also be produced from renewable biomass. Indeed, the fermentative production of hydrogen from renewable biomass using anaerobic bacteria could at least partially reduce our dependence on fossil fuel, decrease the carbon dioxide emissions and produce “green” energy. It offers the potential production of usable hydrogen from a variety of renewable resources such as carbohydrates wastes from agriculture or agro-food industries. This technology is based on anaerobic fermentation, called dark fermentation, by chemotrophic bacteria. The investigations carried out at CWBI involve selection and characterization of bacteria strains able to produce biohydrogen efficiently and with a wide range of substrate. The selected strains at the laboratory has been characterised as Clostridium sp. In order to produce hydrogen at high yields and production rates, the biotechnological process needs to be further optimized and efficient bioreactors must be designed. At CWBI, a new reactor called “horizontal rotating cylinder bioreactor” allows the production of biohydrogen from glucose with our Clostridium sp. strain with a high yield and production rate. This reactor, working continuously, has an internal volume of 2.3l but a working volume (liquid phase) of 300ml. Firstly, it enhances the hydrogen production rate by partially fixing the bacteria on the porous cylinder and thus increasing the cell concentration in the bioreactor. Secondly, the rotative cylinder enables efficient gas transfer (mainly hydrogen) from the liquid phase where it is produced by the bacteria. This is an important way to enhance hydrogen production yield by allowing the bacteria metabolism to shift in a fermentation type that produces more hydrogen. This was confirmed by increasing or decreasing the total pressure in the bioreactor and observing the influence of hydrogen production. The liquid to gas hydrogen transfer is possibly an important factor to enhance the biogas production. Our investigation confirmed this by testing different liquid to gas transfer condition in BHP test (batch fermentation in 250ml serum bottles).This was made either by decreasing total and partial pressure or by increasing the mixing state of the media. Our work concludes the importance of providing good liquid to gas transfers in the biohydrogen producing reactors to enhance the hydrogen production and reach higher yields and production rates. [less ▲]

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