References of "Delvigne, Frank"
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See detailDirect and indirect use of GFP whole cell biosensors for the assessment of bioprocess performances: design of milliliter scale-down bioreactors
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

in Biotechnology Progress (2013), 29(1), 48-59

Substrate limitation responsive biosensors have been used for the development of a mini-bioreactor platform that can be used as a scale-down tool. Three green fluorescent protein (GFP) transcriptional ... [more ▼]

Substrate limitation responsive biosensors have been used for the development of a mini-bioreactor platform that can be used as a scale-down tool. Three green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli, i.e., uspA::gfp, csiE::gfp and yciG::gfp. Our previous studies have shown that these kinds of promoters are induced in response to substrate limitation and are significantly repressed when cultures are carried out in heterogeneous bioreactors. This sensitivity to substrate limitation has been confirmed in the case of the csiE and yciG biosensors. A mini-scale-down platform is proposed as a high throughput tool to rapidly investigate the usefulness of a given microbial biosensor. This platform is composed of shake flasks able to operate in fed-batch mode either using the slow release or the intermittent feeding principle. Local heterogeneities were reproduced at the level of these mini-bioreactors (operating under the intermittent feeding principle) and caused a decrease in GFP expression as in conventional scale-down reactors. The presence of GFP in supernatants was also noted and seems to be correlated with the substrate limitation signal for the three cultivation systems considered in this work (i.e., chemostat, conventional and mini-bioreactors) and with membrane permeability. [less ▲]

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See detailIntégration du stress microbien pour le scaling-up des bioréacteurs
Delvigne, Frank ULg

Scientific conference (2013)

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See detailUtilisation des termites comme source de microorganismes dans la filière de production du bioéthanol de seconde génération
Tarayre, Cédric ULg; Bauwens, Julien ULg; Brasseur, Catherine ULg et al

Poster (2012, November 14)

Les termites abritent une microflore symbiotique qui intervient dans la dégradation des fibres constitutives du bois, synthétisant des enzymes capables d’hydrolyser ses composants. Les sucres ... [more ▼]

Les termites abritent une microflore symbiotique qui intervient dans la dégradation des fibres constitutives du bois, synthétisant des enzymes capables d’hydrolyser ses composants. Les sucres fermentescibles libérés suite à cette hydrolyse sont utilisables dans le cadre de la production du bioéthanol de seconde génération. [less ▲]

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See detailScale-up - scale-down : vers une meilleure intégration industrielle des biotechnologies blanches
Delvigne, Frank ULg

Scientific conference (2012, November 14)

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See detailImplementation of structured metal packing for the design of biofilm reactor : analysis by high energy X-ray tomography and application to the production of lipopeptides by Bacillus subtilis
Zune, Quentin ULg; Soyeurt, Delphine; Ongena, Marc ULg et al

Poster (2012, October 08)

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce ... [more ▼]

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce high added value molecules. Thus, it is required to design new bioreactors able to promote the growth of the biomass on the form of a biofilm and to identify the key physico-chemical parameters involved in order to optimize the bioprocess. 2. Aim of this study was to investigate a pilot-scale biofilm reactor comprising a metal structured packing promoting growth of Bacillus subtilis as a biofilm for the production of lipopeptides, high added value compounds with high surface active properties. 3. In this work, the mechanical stirring system of a 20L stirred tank bioreactor has been removed and replaced by a metal structured packing positioned in the headspace of the vessel above a liquid phase. The culture medium is continuously recirculated on the packing thanks to a peristaltic pump and air supply is performed just above the liquid phase under the packing. High energy X-ray tomography was used to estimate non-invasively the biofilm distribution inside the packing and permitted to define parameters that affect scale-up. Performances of the biofilm reactor were compared with a submerged culture in a stirred tank reactor in terms of lipopeptides production. 4. After 72 hours of fermentation, 94 % of the total biomass adheres onto the metal packing on the form of a biofilm. The colonization of this latter has been visualized non-invasively by X-ray tomography directly inside the packing and shows a conical repartition of the biofilm mass (about 25% of the total volume of the packing) as well as the presence of clogging. However, unlike the submerged culture, no foam formation appeared during fermentation and surfactin yield reaches 345,4 ± 32,8 mg / L for the biofilm reactor against 277,3 ± 34,4 mg / L in the stirred tank reactor. 5. In conclusion, this experimental setting leads to a major technological progress avoiding foam formation and increasing surfactin production. Nevertheless, significant improvements are required at the level of the biofilm distribution in thin layers inside the packing in order to increase mass transfer and lipopeptides recoveries. Further investigations will be devoted to the optimization of the physico-chemical parameters involved in biofilm distribution. [less ▲]

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See detailImplementation of structured metal packing for the design of biofilm reactor : analysis by high energy X-ray tomography and application to the production of lipopeptides by Bacillus subtilis
Zune, Quentin; Soyeurt, Delphine; Ongena, Marc ULg et al

Poster (2012, October 08)

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce ... [more ▼]

1. Whereas multi-species biofilm reactors are commonly used for treatments of water and gas effluents, new strategies are arising for the development of mono-species biofilm reactors in order to produce high added value molecules. Thus, it is required to design new bioreactors able to promote the growth of the biomass on the form of a biofilm and to identify the key physico-chemical parameters involved in order to optimize the bioprocess. 2. Aim of this study was to investigate a pilot-scale biofilm reactor comprising a metal structured packing promoting growth of Bacillus subtilis as a biofilm for the production of lipopeptides, high added value compounds with high surface active properties. 3. In this work, the mechanical stirring system of a 20L stirred tank bioreactor has been removed and replaced by a metal structured packing positioned in the headspace of the vessel above a liquid phase. The culture medium is continuously recirculated on the packing thanks to a peristaltic pump and air supply is performed just above the liquid phase under the packing. High energy X-ray tomography was used to estimate non-invasively the biofilm distribution inside the packing and permitted to define parameters that affect scale-up. Performances of the biofilm reactor were compared with a submerged culture in a stirred tank reactor in terms of lipopeptides production. 4. After 72 hours of fermentation, 94 % of the total biomass adheres onto the metal packing on the form of a biofilm. The colonization of this latter has been visualized non-invasively by X-ray tomography directly inside the packing and shows a conical repartition of the biofilm mass (about 25% of the total volume of the packing) as well as the presence of clogging. However, unlike the submerged culture, no foam formation appeared during fermentation and surfactin yield reaches 345,4 ± 32,8 mg / L for the biofilm reactor against 277,3 ± 34,4 mg / L in the stirred tank reactor. 5. In conclusion, this experimental setting leads to a major technological progress avoiding foam formation and increasing surfactin production. Nevertheless, significant improvements are required at the level of the biofilm distribution in thin layers inside the packing in order to increase mass transfer and lipopeptides recoveries. Further investigations will be devoted to the optimization of the physico-chemical parameters involved in biofilm distribution. [less ▲]

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See detailEffects of glycerol on Pseudomonas fluorescens BTP1 freeze-dried
Mputu Kanyinda, Jean-Noël ULg; Pierart, C.; Weekers, F. et al

in International Journal of Biotechnology and Biochemistry. (2012), 8(2), 245-258

The storage stability of freeze-dried powders was studied by parameters such as loss of viability on the Plate Count Agar (PCA). Powder with glycerol (PG) contains 8.4x1010cfu/g before storage 1 ... [more ▼]

The storage stability of freeze-dried powders was studied by parameters such as loss of viability on the Plate Count Agar (PCA). Powder with glycerol (PG) contains 8.4x1010cfu/g before storage 1.1x1010cfug after 3 months at 4°C and 6.0x108cfu/g after 3 months at 20°C. The concentration of soluble proteins (mg/g) decrease during storage at 4°C from 3.77 to 0.80 after 90 days; and the ratios of unsaturated to saturated fatty acids (C18:3/C16:0 and C18:2/C16:0) decrease respectively from 0.05 to 0.04 and 0.007 to 0.004 after 3 months at 4°C. This ratio characterises the membrane fluidity. Powder without glycerol (PS) contains 1.1x1010 cfu/g before storage and 1.4 x 108 cfu/g after 3 months at 4°C and 1.4 x 107 cfu/g after 3 months at 20°C. The concentration of soluble proteins (mg/g) decrease during storage at 4°C from 4.08 to 0.42 after 90 days, the glutathione concentration decrease during storage at 4°C from 2.2 to 1.4. The beneficial effect of glycerol on fatty acid composition during freezedrying is shown and the ratios of unsaturated to saturated fatty acids (C18:2/C16:0 and C18:3/C16:0) decrease respectively from 0.019 to 0.004 and 0.054 to 0.036 after 90 days storage at 4°C. Analysis by flow cytometry was used to assess the physiological state in which cells are at the end of freeze-drying. We found 13.5% live cells, 36.1% dead cells and 50.4% cells in an intermediate state for powder with glycerol (PG) after freeze-drying. These results shows that glycerol play an important role in Pseudomonas fluorescens BTP1 desiccation during freeze-drying, by maintaining a degree of viability after freeze-drying and during storage. [less ▲]

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See detailDevelopment of optical trajectography device for the lagangian study of turbulent flow inside a stirred tank used in pharmaceutical industry
Collignon, Marie-Laure ULg; Delafosse, Angélique ULg; Delvigne, Frank ULg et al

Poster (2012, September 10)

Stirred tanks are devices that are widely used in various process steps of the pharmaceutical industry. The performance of these processes (animal cell culture, crystallization, flocculation …) strongly ... [more ▼]

Stirred tanks are devices that are widely used in various process steps of the pharmaceutical industry. The performance of these processes (animal cell culture, crystallization, flocculation …) strongly depend on the physico-chemical and hydrodynamic environment present locally in these tanks. To fully describe this local environment, an Eulerian - Lagrangian approach must be adopted in order to establish history of conditions met by a particle as a cell, a crystal or a floc. This approach implies to determine the trajectory followed by the particle. To this aim, the Chemical Laboratory of Liege University has developed a prototype of optical trajectography device. The objective of this paper is to present the device, developments that were necessary for its use and the results obtained. The device is composed of two cameras modeled by a pinhole model which record the position of a bead that has a size equal to 490 µm and that perfectly follows local flow structures. The measured trajectory has been validated by comparing average time velocity fields deduced from it to those measured, in the same operating conditions, by particle image velocimetry (P.I.V.). [less ▲]

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See detailImprovement of the cellulose hydrolysis yields and hydrolysate concentration by management of enzymes and substrate input
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Blecker, Christophe ULg et al

in Cerevisia : Belgian Journal of Brewing and Biotechnology (2012), 37

In order to improve the hydrolysis of cellulose fiber and to obtain highly concentrated hydrolysate, two methods based on successive addition of enzyme and substrate were assessed. The first method, which ... [more ▼]

In order to improve the hydrolysis of cellulose fiber and to obtain highly concentrated hydrolysate, two methods based on successive addition of enzyme and substrate were assessed. The first method, which required only substrate addition, allowed to increase by 50% the hydrolysate concentration and to decrease by 30% enzyme units needed. The second method highlighted the ability to reach very high concentrated hydrolysate (up to 170 g/l) by simultaneous addition of enzyme and substrate. In parallel, relationships between some limiting factors and the yields of hydrolysis were investigated. In conclusion, viscosity evolution of cellulose suspension during hydrolysis step was investigated with an aim to improve the management of enzyme and substrate addition. [less ▲]

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See detailPathogenicity test of the fungus Aspergillus clavatus on aphid Acyrthosiphon pisum (Aphididae)
Seye, Fawrou; Bawin, Thomas ULg; Delvigne, Frank ULg et al

Poster (2012, August 19)

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an ... [more ▼]

Pea aphid is a pest of many cultivated and wild plants, but also a vector of several viral diseases. To control this pest, the most widely used methods are physical, chemical and more recently an integrated approach that includes biological control. With the use of pathogenic agents against insects, the use of entomopathogenic fungi is one of the most promising. The present study demonstrated the possibility of using an entomopathogenic fungus Aspergillus clavatus against aphids. In laboratory conditions (8/16 photoperiod, average temperature 25°C), the insects were in contact with different concentrations ranging from 10^2 to 10^4 spores/cm2 deposited on filter paper in Petri dishes, or applied directly to young plants with doses ranging from 10^4 to 10^6 spores/ml. In 24 hours, mortality was 0 to 31.5% in Petri dishes. For treatment plants, the cumulative mortality in 5 days was 55 to 79%. Microscopic observations showed that the aphids were infected by contact and fungus has a mycosis effect. From these preliminary results, investigations should be made to study the action of the fungus on the reproduction of aphids. Therefore, A. clavatus could be introduced along with other fungi found in the literature as a biological control agent against aphids. [less ▲]

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See detailDevelopment of mini scale-down platform based on the response of GFP microbial biosensors
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

Poster (2012, May 18)

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor ... [more ▼]

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor). Indeed, such heterogeneities cause a lowering of the biomass yield and an increase of by-products concentration. In our previous works, green fluorescent protein reporters have been used as biosensors of the heterogeneities generated in a two compartment scale-down reactor. As there is a huge variety of available whole cell biosensor to characterize the impact of such heterogeneities at the biological level, there is a need for high-throughput cultivation tools in order to investigate the usefulness of a given microbial biosensor among a library comprising several thousands of clones. This work is based on this statement and aims to investigate the potentialities of a mini scale-down platform. Four green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli: rpoS::gfp, uspA::gfp, csiE::gfp and yciG::gfp. The promoters rpoS and uspA are 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 glucose limitation. First, the response of these biosensors has been assessed in chemostat reactors. These kinds of experiments allow easier interpretation of responses of stress gene related to a glucose limitation since the extracellular conditions are constants and cells are renewed. Biosensors carrying the csiE and yciG promoters have exhibited an induction in function of the glucose limitation. Secondly, a scale-down platform has been tested with the same biosensors and two kinds of glucose addition mode. This scale-down platform involves high-throughput cultivation tools, i.e. in our case shake flask, equipped with non-invasive optical sensors for the monitoring of the dissolved oxygen profile in front of the glucose addition mode. The first system is based on a commercial package (Enbase) based on the enzymatic release of glucose in the medium. The Enbase system allows the generation of a very smooth glucose profile without any perturbations. For comparison purpose, we have also used an intermittent feeding that induces strong fluctuation at the level of the glucose and the dissolved oxygen concentration. The intermittent addition of glucose induces a slow down at the level of the GFP synthesis, suggesting that temporal accumulation of glucose inhibits the activity of the yciG and csiE promoters. In conclusion, the scale-down platform is able to reproduce the same kind of glucose fluctuations that encounters the cells in large-scale processes but not allows studying the impact of high-cell density culture on gene expression. [less ▲]

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See detailExtrapolation des bioréacteurs/Bioreactor scale-up
Delvigne, Frank ULg

Scientific conference (2012, May 06)

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See detailUse of microbial biosensors to detect substrate heterogeneities at the single cell level and assess microbial viability: Validation of a mini-bioreactor platform
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

Conference (2012, March 15)

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor ... [more ▼]

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor). Indeed, such heterogeneities cause a lowering of the biomass yield and an increase of by-products concentration. In this work, we have used these biosensors for the elaboration of a mini-bioreactor platform that can be used as a scale-down tool. Three green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli, i.e. uspA::gfp, csiE::gfp and yciG::gfp. Our previous studies have shown that these kinds of promoters are induced in response of substrate limitation and exhibit a strong fluorescence attenuation when cultivated in heterogeneous bioreactors. This sensitivity to substrate limitation has been confirmed in the case of the csiE and yciG biosensors. A mini scale-down platform has been proposed as a high throughput tool to investigate rapidly the usefulness of a given microbial biosensor. This platform is composed of shake flask able to operate in fed-batch mode either by using the slow release or the intermittent feeding principle. The first system is based on a commercial package (Enbase) based on the enzymatic release of glucose in the medium. The Enbase system allows the generation of a very smooth glucose profile without any perturbations. For comparison purpose, we have also used an intermittent feeding that induces strong fluctuation at the level of the glucose and the dissolved oxygen concentration. Local heterogeneities have thus been reproduced at the level of these mini-bioreactors and these one have caused a decrease of GFP expression, as in conventional scale-down reactor. The presence of GFP in supernatants has also been noticed and seems to be correlated with the substrate limitation signal for the three cultivation systems considered in this work (i.e., chemostat, conventional and mini-bioreactors) and with the membrane permeability. [less ▲]

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See detailImpact of glycerol and storage temperature on gluatathione concentration and physiological state of Pseudomonas fluorescens BTP1 freeze-dried
Mputu Kanyinda, Jean-Noël ULg; Pierart, C.; Delvigne, Frank ULg et al

Poster (2012, February 15)

Pseudomonas fluorescens is commonly used as bio-fungicides in agriculture. For this use it requires formulations as either liquid or powder. Formulations have two advantages, storage and transport. Freeze ... [more ▼]

Pseudomonas fluorescens is commonly used as bio-fungicides in agriculture. For this use it requires formulations as either liquid or powder. Formulations have two advantages, storage and transport. Freeze-drying is a commonly used method to preserve bacteria. However, freeze-drying damages the cells, which results in loss of viability. Protective compounds are used to reduce loss of viability during process (freeze-drying and storage). In our study we used flow cytometry analysis to assess the physiological state in which cells are at the end of freeze-drying and Glutathione (GSH) was measured before and during storage. [less ▲]

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See detailDesign of a biofilm reactor comprising a metal structured packing for the production of lipopeptides by B. subtilis
Zune, Quentin ULg; Ongena, Marc ULg; Toye, Dominique ULg et al

Poster (2012, February 08)

Abstract : The design of a new single species biofilm bioreactor has been investigated. Bacillus subtilis S499 has been chosen as a model organism for the production of lipopetides. Nevertheless ... [more ▼]

Abstract : The design of a new single species biofilm bioreactor has been investigated. Bacillus subtilis S499 has been chosen as a model organism for the production of lipopetides. Nevertheless, considering the surface active properties for this kind of metabolite, processes based on submerged culture in stirred-tank bioreactor involve the use of important amount of antifoam and therefore downstream processes are tedious. In this work, an original process was developed with an experimental setting leading to the suppression of foam formation during the culture. B. subtilis S499 makes a biofilm on a stainless steel structured packing in the top of a bioreactor, nutrient and oxygen supply being carried out by the media recirculation as liquid film on the packing. Lipopeptides secreted by biofilm are accumulated in the liquid phase under the packing and can reach concentrations as high as 800 mg/l. The colonization of the packing by the biofilm has been monitored by X-ray tomography. [less ▲]

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See detailEffect of the intensity and frequency of glucose pulse perturbation on transient E. coli behavior : a step toward the large-scale bioreactor
Gorret, Nathalie; Sunya, Sirichai; Uribellarea, Jean-Louis et al

Conference (2012)

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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 ▲]

Detailed reference viewed: 47 (9 ULg)