References of "Delvigne, Frank"
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See detailThe role of protein modifications in senescence of freeze-dried Acetobacter senegalensis during storage
Shafiei, Rasoul ULg; Zarmehrkhorshid, Raziyeh ULg; Bentaib, Azeddine ULg et al

in Microbial Cell Factories (2014)

Background Loss of viability is one of the most important problems during starter culture production. Previous research has mostly focused on the production process of bacterial starters, but there are ... [more ▼]

Background Loss of viability is one of the most important problems during starter culture production. Previous research has mostly focused on the production process of bacterial starters, but there are few studies about cellular protein deterioration causing cell defectiveness during storage. In the present study, we investigated the influence of storage temperature (−21, 4, 35°C) on the cellular protein modifications which may contribute to the senescence of freeze-dried Acetobacter senegalensis. Results Heterogeneous populations composed of culturable cells, viable but non-culturable cells (VBNC) and dead cells were generated when freeze-dried cells were kept at −21 and 4°C for 12 months whereas higher storage temperature (35°C) mainly caused death of the cells. The analysis of stored cell proteome by 2D-DiGE demonstrated a modified pattern of protein profile for cell kept at 4 and 35°C due to the formation of protein spot trains and shift of Isoelectric point (pI). Quantification of carbonylated protein by ELISA showed that the cells stored at 4 and 35°C had higher carbonylated protein contents than fresh cells. 2D-DiGE followed by Western blotting also confirmed the carbonylation of cellular proteins involved in translation process and energy generation. The auto-fluorescent feature of cells kept at 35°C increased significantly which may be an indication of protein glycation during storage. In addition, the percentage of cellular unsaturated fatty acid and the solubility of cellular proteins decreased upon storage of cells at higher temperature suggesting that peroxidation of fatty acids and possibly protein lipidation and oxidation occurred. Conclusions High storage temperature induces some deteriorative reactions such as protein oxidation, lipidation and glycation which may cause further protein modifications like pI-shift, and protein insolubility. These modifications can partly account for the changes in cell viability. It can also be deduced that even moderate carbonylation of some critical cellular proteins (like ribosomal proteins) may lead to VBNC formation or death of freeze-dried bacteria. Moreover, it seems that other mechanisms of biomolecule deterioration preceding protein carbonylation lead to VBNC formation under very low storage temperature. [less ▲]

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See detailHigh-energy X-ray tomography analysis of a metal packing biofilm reactor for the production of lipopeptides by Bacillus subtilis
Zune, Quentin ULg; Soyeurt, Delphine; Toye, Dominique ULg et al

in Journal of Chemical Technology & Biotechnology (2014), 89

BACKGROUND: Whereas multi-species biofilm reactors are commonly used for the treatment of liquid and solid wastes, new strategies are progressing for the development of single species biofilm for the ... [more ▼]

BACKGROUND: Whereas multi-species biofilm reactors are commonly used for the treatment of liquid and solid wastes, new strategies are progressing for the development of single species biofilm for the production of high-value metabolites. Technically, this new concept relies on the design of bioreactors able to promote biofilm formation and on the identification of the key physico-chemical parameters involved in biofilm formation. RESULTS: An experimental setting comprising a liquid continuously recirculated on a metal structured packing has been used to promote Bacillus subtilis GA1 biofilm formation. The colonization of the packing has been visualized non-invasively by X-ray tomography. This analysis revealed an uneven, conical, distribution of the biofilm inside the packing. Compared with a submerged culture carried out in a stirred tank reactor, significant modification of the lipopeptide profile has been observed in the biofilm reactorwith the disappearance of fengycin and iturin fractions and an increase of the surfactin fraction. In addition, considering the biofilm reactor design, no foam formation has been observed during the culture. CONCLUSIONS: The configuration of this biofilm reactor set-up allows for a higher surfactin production by comparison with a submerged culture while avoiding foam formation. Additionally, scale-up could easily be performed by increasing the number of packing elements. [less ▲]

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See detailMicrobial heterogeneity affects bioprocess robustness: Dynamic single cell analysis contribute to understanding microbial populations
Delvigne, Frank ULg; Goffin, Philippe

in Biotechnology Journal (2014), 9(1), 61-72

Heterogeneity or segregation of microbial populations has been the subject of much research, but the real impact of this phenomenon on bioprocesses remains not well understood. The main reason behind this ... [more ▼]

Heterogeneity or segregation of microbial populations has been the subject of much research, but the real impact of this phenomenon on bioprocesses remains not well understood. The main reason behind this lack of knowledge is the difficulty for monitoring microbial population heterogeneity in dynamic process conditions. The main concepts leading to microbial population heterogeneity in the context of bioprocesses have been summarized by two distinct hypotheses. The first one involves the individual history of microbial cells or “path” followed during their residence time inside process equipment. The second one involves a coordinated response of the microbial population as a bet-hedging strategy in order to cope with process-related stresses. The respective contribution of each hypothesis to microbial heterogeneity in bioprocesses is still unclear. This statement illustrates the fact that, although microbial phenotypic heterogeneity has been thoroughly investigated at the fundamental level, the implications of this phenomenon in the context of microbial bioprocesses are still subjected to debate. At this time, automated flow cytometry is the best technique for the investigation of microbial heterogeneity in process conditions. However, dedicated software and relevant biomarkers are needed for its proper integration as a bioprocess control tool. [less ▲]

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See detailEnhancement of thermophillic anaerobic digestion of methane by metal nanoparticles encapsulated in porous silica
Al-Ahmad, Alaa Eddin ULg; Hiligsmann, Serge ULg; Lambert, Stéphanie ULg et al

Poster (2013, December 05)

Increased demand and progressive depletion of fossil fuels, and worldwide concerns about greenhouse gas emissions have resulted in the development of promising technologies for renewable energy production ... [more ▼]

Increased demand and progressive depletion of fossil fuels, and worldwide concerns about greenhouse gas emissions have resulted in the development of promising technologies for renewable energy production. Therefore, potential alternatives for energy generation are intensively studied. One option is the use of biomass feedstock for the production of biogas through anaerobic digestion. This process is a biochemical technological process for the treatment of a wide range of feedstocks (e.g. organic fraction of municipal waste, animal manure and slurry, agricultural crops, etc.) to produce methane-rich biogas which can be used in replacement of fossil fuels in both heat and power generation and as a vehicle fuel. However, there are critical issues, which need to be addressed to make the production of bio-methane techno-economically viable and ecologically acceptable. One of the most important issues is the effect of trace metals addition on anaerobic digestion. These metals can be stimulatory, inhibitory, or even toxic for biochemical reactions, depending on their concentrations. As reported in literature, Ni, Co and Fe are all involved in the methane production biochemical process and serve as cofactors in enzymes which are involved in the biochemistry of methane formation (Zandvoort et al., 2006). Recently, enormous interest has been focused on biological applications of metal nanoparticles NPs due to their small size, high specified surface and their great potential in application to many science fields. The most studied process concerns zero valent palladium and iron NPs improving anaerobic biodegradation of chlorinated hydrocarbons (Windt et al., 2005). Moreover, investigation carried out in our lab showed that iron NPs encapsulated in silicate matrix may enhance hydrogen production by Clostridium butyricum (Beckers et al., 2013). Nevertheless the influences of metal NPs on methane producing anaerobic digestion have seldom been investigated. The present work investigates the enhancement effect of seven different metal NPs on methane production during the thermophilic anaerobic digestion. NPs of Cu, Pd, Pt, Ni, Co, Ag and Fe encapsulated in porous silica (SiO2) to prevent their coagulation and agglomeration, were added at concentration of 10-5mol/L in batch test (125ml serum bottles containing 70mL culture medium with 5g/L acetate monohydrate as the sole carbon substrate. Nickel, cobalt and iron NPs improved methane production from acetate. To confirm the previous results, the NPs were tested at different concentrations (10-4, 10-5, and 10-6 mol/L) with starch and glucose substrates. The results show that the impact increases with the increase of NPs concentrations up to 10-4 mol/L. The modified Gompertz equation was applied to describe the effect of NPs on anaerobic digestion. According to this model, the kinetic of methane production was particularly affected by nanoparticles addition. The values of the maximum methane production rate MPR (ml/day) was significantly higher 72.5% with nickel NPs at a concentration of 10-4 mol/L than the control without NPs. [less ▲]

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See detailBioRefine: Recovery of Nutrients from Sewage Sludge, Manure and Digestate by a Combination of Chemical and Biochemical Unit Operations
Tarayre, Cédric ULg; Delvigne, Frank ULg; Michels, Evi et al

Poster (2013, December)

At this time, many wastes are exploited through processes that do not really consider applications potentially more profitable. Such wastes contain reusable components, such as nitrogen, phosphorus and ... [more ▼]

At this time, many wastes are exploited through processes that do not really consider applications potentially more profitable. Such wastes contain reusable components, such as nitrogen, phosphorus and potassium, whereas heavy metals may also be considered. Their composition depends on input materials, and considerable heterogeneities must be highlighted. Sewage sludge is usually exploited as a fertilizer in agriculture, in energy production or in the field of construction. The main application of manure is agriculture, although considerable amounts of nutrients are lost and cause pollution. Digestate is also used in agriculture, but other alternatives have been proposed, such as combustion. The use of waste in agriculture must respect many legal constraints. Another problematic point is the concentration of heavy metals that is found in those wastes. Consequently, recovery of nutrients and trace elements may be a key solution. Chemical and biochemical engineering propose many unit operations (mechanical operations on fluids, solids, mass and heat transfers, chemical reactions, etc.) that may be used to reach an efficient recovery yield of capital nutrients and trace elements. Here, we propose a methodology which consists in considering the unit operations separately with their own input and output flows, energy and heat consumption, investment, etc. and combining them to simulate industrial processes. The element concentrations and their forms will also be considered using a classification matrix. Combinations of unit operations will lead to reliable processes that should be applied on an industrial scale. This work is supported by the BioRefine Project, a European project in which various member states focus on recovery of inorganics from organic waste streams. We gratefully acknowledge the INTERREG IVB NWE programme, which financed the BioRefine Project (ref. 320J-BIOREFINE). [less ▲]

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See detailUse of on-line flow cytometry for the characterization of physiological behavior in stress conditions during the bioprocess
Brognaux, Alison ULg; Han, Shanshan; Soren, Sorensen et al

Poster (2013, November 15)

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See detailPrésentation des projets Interreg IVB BIOREFINE et RENEW
Tarayre, Cédric ULg; Delvigne, Frank ULg; Destain, Jacqueline ULg et al

Conference (2013, October 22)

Les projets BioRefine et Renew sont financés par le programme de coopération européen Interreg IVB. Leur but est de promouvoir les transferts de compétences, d'informations et de matières entre les ... [more ▼]

Les projets BioRefine et Renew sont financés par le programme de coopération européen Interreg IVB. Leur but est de promouvoir les transferts de compétences, d'informations et de matières entre les différents pays de la zone européenne du Nord-Ouest. Le projet BioRefine a pour but de récupérer les nutriments (N, P et K) ainsi que les éléments traces métalliques à partir de déchets bien spécifiques: le fumier, le lisier, les digestats de méthanisation et les boues de stations d'épuration. Cette récupération requiert l'élaboration de procédés industriels mis en place après une étude en laboratoire. Le projet Renew, lui, est beaucoup plus général. En ce qui concerne le rôle de Gembloux Agro-Bio Tech dans le projet, le travail sera essentiellement focalisé sur la production d'acide succinique à partir de déchets. Cette production sera assurée par la souche bactérienne Actinobacillus succinogenes. [less ▲]

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See detailUse of on-line flow cytometry to detect segregation in the microbial population
Brognaux, Alison ULg; Zune, Quentin ULg; Han, Shanshan et al

Poster (2013, October 08)

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See detailStress microbien lors du processus d’extrapolation: Approche physique et biologique
Lejeune, Annick ULg; Thonart, Philippe ULg; Delvigne, Frank ULg

in Cerevisia : Belgian Journal of Brewing and Biotechnology (2013), 38(3), 89-101

Les micro-organismes sont utilisés dans de nombreux domaines (agro-alimentaire, pharmaceutique, environnemental, énergétique,…) que ce soit pour la production de biomasse ou de métabolites particuliers ... [more ▼]

Les micro-organismes sont utilisés dans de nombreux domaines (agro-alimentaire, pharmaceutique, environnemental, énergétique,…) que ce soit pour la production de biomasse ou de métabolites particuliers. Le passage de l’échelle du laboratoire à l’échelle industrielle est souvent problématique car les micro-organismes sont sensibles aux conditions environnementales développées au sein du volume réactionnel. De plus, la perte de l’efficacité d’homogénéisation des bioréacteurs industriels entraîne des perturbations au niveau du métabolisme des cellules. C’est pourquoi il est important d’étudier les conditions hydrodynamiques développées au sein du réacteur. Cet article présente des méthodes de calcul et de modélisation de ces conditions. L’impact de l’hydrodynamique sur le métabolisme microbien peut être étudié par l’utilisation de réacteurs scale-down. Les techniques nouvelles permettant de réaliser un scale-up prennent en compte des caractères physiologiques des cellules, qui estiment l’impact des conditions environnementales sur le métabolisme microbien et donc la bonne réussite du procédé. Enfin, l’étude de Saccharomyces cerevisiae, micro-organisme de grand intérêt biotechnologique, est réalisée. [less ▲]

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See detailDéveloppement d'un dispositif de trajectographie optique nécessaire pour la caractérisation expérimentale par une approche Euler-Lagrange des écoulements dans des bioréacteurs à cuve agitée
Collignon, Marie-Laure ULg; Delafosse, Angélique ULg; Delvigne, Frank ULg et al

in Récents Progrès en Génie des Procédés (2013, October)

Les bioréacteurs à cuve agitée sont des dispositifs largement utilisés dans l’industrie pharmaceutique. Les performances globales des cultures menées dans ces bioréacteurs dépendent fortement de ... [more ▼]

Les bioréacteurs à cuve agitée sont des dispositifs largement utilisés dans l’industrie pharmaceutique. Les performances globales des cultures menées dans ces bioréacteurs dépendent fortement de l’environnement physico-chimique et hydrodynamique local rencontré par les microorganismes et ce au cours du temps. Pour parvenir à caractériser cet historique de conditions locales rencontrées, une approche Euler-Lagrange doit être adoptée. La difficulté dans ce type d’approche est d’être capable de mesurer de manière fiable la trajectoire suivie par le microorganisme au sein du bioréacteur. Pour ce faire, le Laboratoire de Génie Chimique de l’Université de Liège a conçu un dispositif de trajectographie optique. L’objectif de cet article est de présenter ce dispositif, les développements qui ont été nécessaire à sa mise en œuvre et les résultats obtenus. Le dispositif se compose de deux caméras observant selon deux axes de l’espace un bioréacteur rétro-éclairé par des panneaux leds. La trajectoire suivie par une particule noire en gel d’alginate de calcium de 491 µm de diamètre est construite à partir des images acquises par ces deux caméras préalablement modélisée par un modèle pinhole et traitées par une approche rationnée. La validité des trajectoires mesurées a été prouvée dans un bioréacteur de 20 L mélangé par une hélice TTP en comparant les champs de vitesse moyen et d’énergie cinétique turbulent extraits de la trajectoire avec ceux obtenus par la technique eulérienne Stéréo P.I.V. La convergence de ces deux champs avec le temps d’acquisition de la trajectoire a également été démontrée. [less ▲]

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See detailTracking the growth of Trichoderma reesei during HFBII production - CO2 -HFBII foam
Khalesi, Mohammadreza; Riveros-Galan, David; Deckers, Sylvie et al

Poster (2013, July 21)

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See detailPhysiological response of yeast to process perturbations: A mini-bioreactor approach
Lejeune, Annick ULg; Delvigne, Frank ULg; Thonart, Philippe ULg

in Cerevisia : Belgian Journal of Brewing and Biotechnology (2013), 38(1), 15-19

Large-scale production of yeast (Saccharomyces cerevisiae) is difficult to control, considering the drop of mixing and mass transfer efficiency during scale-up. The drop of hydrodynamic efficiency in ... [more ▼]

Large-scale production of yeast (Saccharomyces cerevisiae) is difficult to control, considering the drop of mixing and mass transfer efficiency during scale-up. The drop of hydrodynamic efficiency in large-scale bioreactors induces the formation of heterogeneities, i.e. mainly substrate and dissolved oxygen in process conditions. These extracellular fluctuations have several impacts at the level of the physiology of microorganisms, from metabolic shift to specific gene expression (stress response). Microbial cell responses to extracellular fluctuations are actually not fully understood. In this work, we propose to reproduce the main extracellular fluctuations at the level of a mini bioreactor platform. These mini-reactors are shake flasks equipped with dissolved oxygen probes. The cultures are realized with different fed-batch control strategies. A scale-down approach has been developed by considering slow release techniques and intermittent feeding, in order to reproduce the glucose and dissolved oxygen fluctuations experienced in large-scale reactors. The mini-reactor has been used to screen the response of several green fluorescent protein (GFP) reporter strains (adh2, tps2, pdc6 and hxt2). The GFP content of cells has been determined by flow cytometry in order to take into account population heterogeneity. In front of these results, the methodology presented in this work can be proposed as a scale-down tool. [less ▲]

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See detailApplication of three entomopathogenic fungi for aphid control
Bawin, Thomas ULg; Seye, Fawrou; Boukraa, Slimane ULg et al

Poster (2013, May 21)

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Chemical pesticide application is the most commonly used method for aphid control. Due to ... [more ▼]

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Chemical pesticide application is the most commonly used method for aphid control. Due to rapid developments of resistance to pesticides and environmental pollution, integrated pest management, including biological control was promoted. In this context, entomopathogenic fungi are valuable tools for potential aphid control since various fungal strains are already commercially available. The present study aims to evaluate and compare the insecticidal activity of two Metarhizium and one Aspergillus strains against Acyrthosiphon pisum aphid. Fungi were cultivated on wheat bran media in flasks up to sporulation. The solid media were washed with aqueous solutions containing 0.05% Tween 80 before filtration. The content of conidia was determined by haemocytometer. Doses ranging from 10^3 to 10^7 conidia/ml were then applied on young plants with 20 adult parthenogenetic aphids. Batches were incubated at a 16L/8D photoperiod, 25±2°C and 75-80% relative humidity. Adult mortality was assessed in order to determine LD50, LD90 and LT50 values, and the number of nymphs produced was daily recorded. Five days after treatment, mortality rates ranged from 30 to 91% depending on the fungal strain and tested dose. Corresponding LD50 and LD90 values were 1.23 x 10^3 and 1.34 x 10^7, 3.67 x 10^3 and 9.71 x 10^7, 4.95 x 10^2 and 5.65 x 10^7 conidia/ml for Metarhizium sp., Metarhizium anisopliae and Aspergillus clavatus respectively. At the higher dose, the LT50 were reached within 2, 4 and 3 days respectively, whereas the LT50 were never reached in the controls. By contrast, the intrinsic growth rates were significantly different from uninfected aphids only in the case of A. clavatus with 10^6 and 10^7 conidia/ml doses five days after exposure. In conclusion, these fungal isolates induced A. pisum mortality with a similar impact and A. clavatus infection appeared to alter the adults’ fitness. This suggests that these fungi may be candidates for aphid control. Further investigations should be made in order to assess their host range specificity. Toxic metabolites leading to death have to be identified and their safety towards non-target organisms confirmed. Finally, their persistence in the environment as well as the compatibility with over means of aphid control must be verified in a view of a broad integrated pest management. [less ▲]

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