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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 detailReprogramming of fatty acid and oxylipin synthesis in rhizobacteria-induced systemic resistance in tomato
Mariutto, Martin; Fauconnier, Marie-Laure ULg; Ongena, Marc ULg et al

in Plant Molecular Biology (2013), 84(4-5), 455-476

The rhizobacterium Pseudomonas putida BTP1 stimulates induced systemic resistance (ISR) in tomato. A previous work showed that the resistance is associated in leaves with the induction of the first enzyme ... [more ▼]

The rhizobacterium Pseudomonas putida BTP1 stimulates induced systemic resistance (ISR) in tomato. A previous work showed that the resistance is associated in leaves with the induction of the first enzyme of the oxylipin pathway, the lipoxygenase (LOX), leading to a faster accumulation of its product, the free 13-hydroperoxy octadecatrienoic acid (13-HPOT), 2 days after Botrytis cinerea inoculation. In the present study, we further investigated the stimulation of the oxylipin pathway: metabolites and enzymes of the pathway were analyzed to understand the fate of the 13-HPOT in ISR. Actually the stimulation began upstream the LOX: free linolenic acid accumulated faster in P. putida BTP1-treated plants than in control. Downstream, the LOX products 13-fatty acid hydroperoxides esterified to galactolipids and phospholipids were more abundant in bacterized plants than in control before infection. These metabolites could constitute a pool that will be used after pathogen attack to produce free fungitoxic metabolites through the action of phospholipase A2, which is enhanced in bacterized plants upon infection. Enzymatic branches which can use as substrate the fatty acid hydroperoxides were differentially regulated in bacterized plants in comparison to control plants, so as to lead to the accumulation of the most fungitoxic compounds against B. cinerea. Our study, which is the first to demonstrate the accumulation of an esterified defense metabolite during rhizobacteria-mediated induced systemic resistance, showed that the oxylipin pathway is differentially regulated. It suggests that this allows the plant to prepare to a future infection, and to respond faster and in a more effective way to B. cinerea invasion. [less ▲]

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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 detailANAEROBIC DIGESTION OF ORGANIC WASTES FROM AGRO-FOOD ACTIVITIES IN TUNISIA
Mhiri, F; Hiligsmann, Serge ULg; Sayahi, L. et al

Poster (2013, October 01)

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See detailMONITORING OF ANAEROBIC DIGESTION IN MSW LANDFILLS IN TUNISIA
Mhiri, F.; Hiligsmann, Serge ULg; Sayahi, L. et al

in Proceedings Sardinia 2013 (2013, October)

The monitoring of two controlled landfills in Tunisia was carried out for about 10 years by CITET and CWBI. Both landfills were managed by classical methodology i.e. disposal, compaction and, if any ... [more ▼]

The monitoring of two controlled landfills in Tunisia was carried out for about 10 years by CITET and CWBI. Both landfills were managed by classical methodology i.e. disposal, compaction and, if any, biogas and leachate extraction and treatment. One of them is located near Tunis and the other near Sousse with a warmer climate. They received more than 6,000 and 350 thousand cubic metre of MSW respectively from the two cities. Solid samples were collected by boring at different depths up to 18 m. They were analysed for dry weight and for total organic carbon, nitrogen and (hemi-) cellulose. The boreholes were equipped with 200 mm perforated PEHD tubes for further biogas and leachate sampling and analyses (COD, VFA, CH4 content, …) at different seasons. The results indicate an efficient mesophilic anaerobic digestion in both landfills. The high dry weight content (70 – 92%) of 13 solid samples collected in Sousse landfill contrasts however with the high leachate production in the Tunis landfill, filling about completely the majority of boreholes. The results of this monitoring confirm the trends formerly described about biological activity and environmental impact of landfills in Tunisia. Moreover a 200 L pilot-scale anaerobic digester was operated for about 3 years with solid wastes from Tunis landfill to assess the evolution of moisture content and organic matter. [less ▲]

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See detailANAEROBIC DIGESTION WITH BIOHYDROGEN PRODUCTION FROM ORGANIC WASTES : STATE-OF-THE ART
Hiligsmann, Serge ULg; Beckers, L.; Hamilton, C. et al

in Proceedings Sardinia 2013 (2013, October)

Hydrogen (H2) is being considered as an ideal and clean energy carrier since the utilization of hydrogen, either via combustion or via fuel cells, results in pure water. However, currently its production ... [more ▼]

Hydrogen (H2) is being considered as an ideal and clean energy carrier since the utilization of hydrogen, either via combustion or via fuel cells, results in pure water. However, currently its production relies mainly (i.e. 95%) on fossil fuels. 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 called “dark fermentation” enables both organic waste treatment and renewable energy production to be coupled. The soluble metabolites, mainly acetate and butyrate, contained in the spent medium of the dark fermentation bioreactor may be efficiently converted to methane in a second anaerobic digester treating other carbon sources. The paper reviews the state-of-the art on the challenges and prospective applications of dark fermentation as a first step of anaerobic digestion of municipal solid wastes to produce H2 and CH4. [less ▲]

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See detailStudy of the sorption behavior of Hibscus sabdariffa anthocyanins on a macroporous resin
Beye, Cheikh ULg; Souk Tounkara, Lat; Destain, Jacqueline ULg et al

in Journal of Food Process Engineering (2013), 36(5), 579-590

The adsorption of Hibiscus sabdariffa sp. anthocyanins onto a macroporous resin was studied in laboratory experiments. The anthocyanin aqueous extracts obtained from the calyces were used in agitated ... [more ▼]

The adsorption of Hibiscus sabdariffa sp. anthocyanins onto a macroporous resin was studied in laboratory experiments. The anthocyanin aqueous extracts obtained from the calyces were used in agitated batch experiments with a macroporous resin. The adsorption kinetics and isotherms of H. sabdariffa anthocyanins on a selected macroporous resin was studied to determine the parameters that have to be optimized to recover the anthocyanins from aqueous extracts of the calyces. The adsorption kinetic experimental data were fit into a pseudo second order kinetic model, which was then used to determine several parameters such as the contact time necessary to reach equilibrium as well as the maximum adsorption capacity. The best fit for the equilibrium adsorption isotherm experimental data was obtained with the Langmuir isotherm model. Based on qualitative and quantitative interpretation of the experimental data, the resin that was tested here appeared to have good adsorption capacity for the anthocyanins even though the necessary time to reach equilibrium was particularly long. Three aspects of the desorption of anthocyanins from the resin were studied: the speed of release of the anthocyanins (desorption kinetics), the extent of the anthocyanin desorption depending on the adsorption contact time and finally, the influence of the mobile phase's characteristics [less ▲]

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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 detailProteomic Investigation of Aphid Honeydew Reveals an Unexpected Diversity of Proteins
Sabri, Ahmed; Vandermoten, Sophie ULg; Leroy, Pascal et al

in PLoS ONE (2013), 8(9),

Aphids feed on the phloem sap of plants, and are the most common honeydew-producing insects. While aphid honeydew is primarily considered to comprise sugars and amino acids, its protein diversity has yet ... [more ▼]

Aphids feed on the phloem sap of plants, and are the most common honeydew-producing insects. While aphid honeydew is primarily considered to comprise sugars and amino acids, its protein diversity has yet to be documented. Here, we report on the investigation of the honeydew proteome from the pea aphid Acyrthosiphon pisum. Using a two-Dimensional <br />Differential in-Gel Electrophoresis (2D-Dige) approach, more than 140 spots were isolated, demonstrating that aphid honeydew also represents a diverse source of proteins. About 66% of the isolated spots were identified through mass spectrometry analysis, revealing that the protein diversity of aphid honeydew originates from several organisms (i.e. the host aphid and its microbiota, including endosymbiotic bacteria and gut flora). Interestingly, our experiments also allowed to identify some proteins like chaperonin, GroEL and Dnak chaperones, elongation factor Tu (EF-Tu), and flagellin that might act as mediators in the plant-aphid interaction. In addition to providing the first aphid honeydew proteome analysis, we propose to reconsider the importance of this substance, mainly acknowledged to be a waste product, from the aphid <br />ecology perspective. [less ▲]

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See detailSemi-Continuous Fermentation for Gluconic acid Production at High Temperature
Zarmehrkhorshid, Raziyeh ULg; Shafiei, Rasoul ULg; Thonart, Philippe ULg

in World Acadamy of Science, Engineering and Technology (2013, July 31)

Gluconic acid (GA) is a multifunctional organic acid with versatile applications in food, beverage and pharmaceutical industries. Recently, owing to increasing demand for cheaper gluconic acid and its ... [more ▼]

Gluconic acid (GA) is a multifunctional organic acid with versatile applications in food, beverage and pharmaceutical industries. Recently, owing to increasing demand for cheaper gluconic acid and its salts; studies have mainly focused on more economical production process through using cheaper carbohydrate sources and isolation of appropriate microorganism. Despite progress towards its microbial production, fewer studies are available regarding its bacterial production at high temperature. It is believed that, withstanding high temperature during production of this acid can provide a new option for industrially cost effective production through reduction in cost of cooling. Results: A major challenge associated with semi-continuous process of gluconate production using A. senegalensis was inability in glucose consumption during the late stationary phase and next fermentation cycles. Inactivation of respiration system (total dehydrogenases activity) and entrance of cells into viable but nonculturable (VBNC) state during stationary phase were the main reasons of this inability. Conclusions: To improve gluconic acid fermentation at high temperature, it is necessary to induce the activity of total dehydrogenases as they carry the oxidation reaction of glucose. Supplementing the feed with ethanol, successfully conferred ability to cells for further glucose consumption. [less ▲]

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