http://hdl.handle.net/2268/140 Search this channel search http://orbi.ulg.ac.be/simple-search http://hdl.handle.net/2268/148611 Title: Photobioreactors for efficient production of molecules with high added value, based upon an innovative technology for the production of porous materials <br/> <br/>Author, co-author: Tocquin, Pierre http://hdl.handle.net/2268/148043 Title: Apply and develop multiplex PCR to detect Fasciola gigantica infection in Lymnaea viridis at different larval stages <br/> <br/>Author, co-author: Bui Thi, Dung <br/> <br/>Abstract: Multiplex PCR was used to detect Fasciola gigantica infection in Lymnaea viridis snail as intermediate host. In this study, snail Lymnaea viridis was experimentally infected with F.gigantica and used for DNA template. Fasciola specific primers was amplified a 124 bp fragment in multiplex PCR when the genomic DNA isolated from F.gigantica infected Lymnaea viridis snails was used as template and amplified a 500 - 600 bp fragment. Genomic DNA of the parasite was used as a positive control, which also gave an amplification of the 124 bp fragment. DNA isolated from non-infected snails was used as a negative control and no amplification of this sequence was observed. The developed diagnostic multiplex PCR will be of use for assessment of transmission of fascioliasis in snail as intermediate host in Vietnam. http://hdl.handle.net/2268/148042 Title: Distribution of freshwater snails in family-based VAC ponds and associated waterbosied with special reference to intermediate hosts of fish-borne zoonotic trematides in Nam Dinh province, Vietnam <br/> <br/>Author, co-author: Bui Thi, Dung <br/> <br/>Abstract: Fish-borne zoonotic trematodes, such as Clonorchis sinensis, heterophyids and others, constitute a public health concern in parts of northern Vietnam and infections with these trematodes are often thought to be linked to fish culture. One common fish culture system is the integrated fish-livestock (VAC) ponds where individual households have 1 or more ponds. Fish fry, mainly of various carp species, pro-duced in hatcheries, not necessarily local, are introduced into nursery ponds and after approximately 6 weeks, juvenile fishes are transferred to household ponds, referred to as grow-out ponds. Grow-out ponds are usually fertilized with organic debris, including animal excreta, to stimulate algal growth and subsequently fish growth. This paper describes the distribution of freshwater snails and occurrence of trematode infections in these in VAC ponds and associated habitats as part of a major study on risk factors of FZT infections in cultured fish in two communes, Nghia Lac and Nghia Phu, Nghia Hung District, Nam Dinh Province. The area is under intense rice cultivation with an extensive canal network supplying fields and also household VAC ponds. A total of 16 snail species was found and four were widely distributed i.e. Angulyagra polyzonata, Melanoides tuberculata, Bithynia fuchsiana and Pomacea insularum. Snail diver-sity and counts were higher in nursery ponds than in grow-out ponds. Species of the families Thiaridae and Viviparidae were more abundant than other species in VAC ponds while species of the Bithyniidae, Stenothyridae and Planorbidae dominated in rice fields and small canals. Trematode infections were found in eight snail species and among these M. tuberculata had the highest overall prevalence of infec-tion (13.28%). No trematode infections were found in species of the Viviparidae and Ampullaridae except for metacercariae. Parapleurolophocercous and pleurolophocercous cercariae constituted the most com-mon type of cercariae recovered, contributing 40.6% of all infections followed by echinostome cercariae (35.0%) and xiphidiocercariae (17.3%). Bithynia fuschiana and M. tuberculata had the most diverse trema-tode fauna. C. sinensis was not recorded in this study. The VAC pond system in this area, is very important for transmission of minute intestinal trematodes while they play little role in transmission of C. sinensis as its intermediate hosts, bithynid snails, rarely occur in these ponds. From a public health perspective this is positive as the effects of infections with intestinal trematodes are considered mild. On the other hand it is possible that even such subtle effects could have importance in public health as transmission is very intense in the area. And this in combination with the aquaculture importance, reduced marketability of fishes with high metacercariae loads, warrants that control efforts against these trematodes are initiated to reduce transmission in this production system. http://hdl.handle.net/2268/147889 Title: Valorisation des produits issus des feuilles de betteraves : extraction de molécules à note verte <br/> <br/>Author, co-author: Marlier, Michel; Thonart, Philippe; du Jardin, Patrick; Ongena, Marc; Fauconnier, Marie-Laure http://hdl.handle.net/2268/147888 Title: Valorisation des produits issus des feuilles de betteraves : extraction de molécules à note verte - Rapport final <br/> <br/>Author, co-author: Wathelet, Jean-Paul; Thonart, Philippe; du Jardin, Patrick; Ongena, Marc; Fauconnier, Marie-Laure http://hdl.handle.net/2268/147887 Title: Valorisation des produits issus des feuilles de betteraves : extraction de molécules à note verte <br/> <br/>Author, co-author: Wathelet, Jean-Paul; Thonart, Philippe; du Jardin, Patrick; Ongena, Marc; Fauconnier, Marie-Laure http://hdl.handle.net/2268/147644 Title: THE RESPONSE OF ACETOBACTER SENEGALENSIS TO STRESSORS: A STUDY TOWARDS IMPROVEMENT OF VINEGAR STARTER PRODUCTION <br/> <br/>Author, co-author: Shafiei, Rasoul; Thonart, Philippe <br/> <br/>Abstract: Acetic acid bacteria encounter various harsh conditions during acetic acid fermentation. Ethanol as the main substrate and acetic acid as the major product at low pH can influence deeply on the cellular functions of acetic acid bacteria. In previous studies in CWBI, Acetobacter senegalensis was used for production of dried vinegar starters; however the impact of stressors (ethanol and acetic acid) on A. senegalensis remained unclear. In this study, different techniques such as flow cytometry, culturability on solid medium and 2-DiGE were used comparatively to investigate the effect of carbon sources of inoculum media on the tolerance of A. senegalensis to stressors. Analysis of respiration system by flow cytometric methods showed that the presence of 2% (v/v) acetic acid in inoculum medium, in one hand, causes 80% of cells to continue to do respiration after a sudden exposure to 1- 3% (v/v) acetic acid in stress media while 89.7% of cells grown in glucose appeared as dead cells after an abrupt exposure to 3%(v/v) of acetic acid. On the other hand, 59.2% and 49.33% of cells grown in the presence of 2% (v/v) of acetic acid could maintain their entire membrane integrity after exposure to 1% and 3% (v/v) of acetic acid, respectively. Inoculum medium contained 5% (v/v) of ethanol as a carbon source enabled about 90% of cells to keep their growing capacities after a sudden exposure to 3% acetic acid. In contrast, just 40% of cells grown in glucose as a carbon source maintained their culturability on solid medium after exposure to 1% acetic acid. A similar profile of culturability was observed for the cells grown in 5% (v/v) ethanol or 2% (v/v) of acetic acid. A proteomic approach (2-DiGE) was used to analyze proteins expressed in the presence of different carbon sources. Differentially expressed proteins were mainly associated with energy metabolism, carbohydrate metabolisms, folding, sorting and degradation processes. The relative abundance of proteins was extensively different for cell grown in glucose compared with protein contents of cells grown in ethanol or acetic acid. In conclusion, production of a cost effective vinegar starter needs a qualified biomass which tolerates ethanol and acetic acid. Tolerance of A. senegalensis to acetic acid depends to a great extent on the composition of the medium which cells grow in. In spite of low adaption to acetic acid for cell grown in glucose, using ethanol or acetic acid in inoculum media renders a physiological state in A. senegelensis which enables it to cope with higher concentration of acetic acid readily, this biomass has a potential to be used as a starter. http://hdl.handle.net/2268/147643 Title: Flow-cytometric assessment of damages to Acetobacter senegalensis during freeze-drying process and storage <br/> <br/>Author, co-author: Shafiei, Rasoul; Delvigne, Frank; Thonart, Philippe <br/> <br/>Abstract: Downstream processes have great influences on bacterial starter production. Different modifications occur to cellular compounds during freeze-drying process and storage of bacterial starters. Consequently, viability and culturability (multiplication capacity) undergo some changes. In this study, the effects of freeze-drying process and storage conditions were examined on cell envelope integrity, respiration and culturability of Acetobacter senegalensis. Freezing of cells protected with mannitol (20% w/w) did not affect cell multiplication and respiration considerably; however, 19% of cells showed compromised cell envelope after freezing. After drying, 1.96×1011 CFU/g were enumerated, indicating that about 34% of the cells could survive and keep their culturability. Drying of the cells induced further leakage in cell envelope and finally 81% of cells appeared as injured ones; however, 87% of the dried cells maintained their respiration capacity. Storage temperature had significant effect on cell multiplication ability; higher storage temperature (35°C),caused 8.59-log reduction in cell culturability after nine-month period of storage. Collapse of cell envelop integrity and respiration wasobserved at 35°C. At lower storage temperature (4°C), the culturability decreased about one-log reduction after nine months. Cell envelope integrity was subjected to minor changes during a period of nine month-storage at 4°C whereas a heterogeneous population of cells with different respiration capacity emerged at 4°C. These results indicate that a major part of cells undergone drying process and storage entered into viable but non-culturable state. In addition, usage of different culture media didn’t improve resuscitation. Besides, it seems that sub-lethal damages to cell envelope caused uptake of propidium iodide, however these kinds of injuries could not impress cell multiplications and respiration. http://hdl.handle.net/2268/147561 Title: Improvement of gluco-amylase B excretion by Aspergillus oryzae in a biofilm reactor <br/> <br/>Author, co-author: Zune, Quentin; Kinet, Romain; Toye, Dominique; Thonart, Philippe; Punt, Peter J; Delvigne, Frank http://hdl.handle.net/2268/147402 Title: Potentiality of using microbial biosensors for the detection of sub-strate 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 <br/> <br/>Author, co-author: Brognaux, Alison; Neubauer, Peter; Twizere, Jean-Claude; Thonart, Philippe; Delvigne, Frank http://hdl.handle.net/2268/147401 Title: On-line flow cytometry profiling of Escherichia coli stress response <br/> <br/>Author, co-author: Brognaux, Alison; Han, Shanshan; Sorensen, Soren; Lebeau, Frédéric; Thonart, Philippe; Delvigne, Frank http://hdl.handle.net/2268/147397 Title: On-line profiling of Escherichia coli stress response <br/> <br/>Author, co-author: Brognaux, Alison; Shanshan, Han; Sorensen, Soren; Lebeau, Frédéric; Thonart, Philippe; Delvigne, Frank http://hdl.handle.net/2268/147396 Title: On-line flow cytometry to detect cell growth rate and membrane damage during bioprocess: focus on the segregation of the microbial population <br/> <br/>Author, co-author: Brognaux, Alison; Han, Shanshan; Sorensen, Soren; Lebeau, Frédéric; Thonart, Philippe; Delvigne, Frank http://hdl.handle.net/2268/147387 Title: Real-time monitoring of cell viability and cell density on the basis of a three dimensional optical reflectance method (3D-ORM): investigation of the effect of sub-lethal and lethal injuries <br/> <br/>Author, co-author: Brognaux, Alison; Bugge, Jörg; Schwartz, Friedel; Thonart, Philippe; Telek, Samuel; Delvigne, Frank <br/> <br/>Abstract: Cell density and cell viability have been followed on-line by using a three-dimensional optical reflectance method (3D-ORM) probe. This method has allowed to highlight the differences between a well-mixed and a scale-down bioreactor configured in order to reproduce mixing deficiencies during a fed-batch culture of E. coli. These differences have been observed both for the obscuration factor (OBF) and the coincidence probability (COP) delivered by the probe. These parameters are correlated to flow cytometry measurement based on the PI-uptake test and cell density based on optical density measurement. This first set of results has pointed out the fact that the 3D-ORM probe is sensitive to sub-lethal injuries encountered by microbial cells in process-related conditions. The effect of lethal injuries has been further investigated on the basis of additional experiments involving heat stress and a sharp increase of the OBF has been observed indicating that cells are effectively injured by the increase of temperature. However, further improvement of the probe are needed in order to give access to single-cell measurements. http://hdl.handle.net/2268/147383 Title: Characterization of the extracellular proteome of Escherichia coli according to the scale-up of bioprocesses and correlation with membrane permeability <br/> <br/>Author, co-author: Brognaux, Alison; Francis, Frédéric; Twizere, Jean-Claude; Thonart, Philippe; Delvigne, Frank http://hdl.handle.net/2268/147333 Title: Bioraffinerie végétale : chimie et technologie des structures osidiques (TECHNOSE) <br/> <br/>Author, co-author: Michiels, Franck; Paquot, Michel; Wathelet, Jean-Paul; Fauconnier, Marie-Laure; Blecker, Christophe; Declerck, Stephan; Brasseur, Robert http://hdl.handle.net/2268/147143 Title: Occurrence of polyfunctional thiols in sorghum beer "ikigage" made with Vernonia amygdalina "umubirizi" <br/> <br/>Author, co-author: Lyumugabe Loshima, François <br/> <br/>Abstract: Several polyfunctional thiols have been previously identified in beers made from barley and hops. These compounds have not been investigated in beers brewed with non-Western raw materials. Here we have performed a thiol-specific extraction with p-hydroxymercuribenzoic acid on a traditional ikigage sorghum beer from Rwandese peasants (use of Vernonia amygdalina just for yeast propagation), and on two pilot beers with addition (or not) of V. amygdalina in the boiling kettle, instead of hops. Gas chromatography – olfactometry, gas chromatography –mass spectrometry and gas chromatography with pulsed flame photometric detectionanalyses of the extracts enabledustoidentify 14polyfunctional thiols.The well-known ho pconstituent3-methyl-2-buten-1-thiol emerged as a key flavour in the unhopped beers containing V. amygdalina flavour dilution >262 144). The addition of V. amygdalina during boiling also resulted in the presence of 1-butanethiol, but the production of 2-sulfanylethanol and 2-sulfanylethyl acetate was inhibited. Complementary data are required to understand how V. amygdalina leaves are able to impact upon the Ehrlich pathway leading to cysteine and homocysteine-derived thiols. <br/> <br/>Commentary: Article publié en collaboration avec l'unité de brasserie de l'université catholique de Louvain http://hdl.handle.net/2268/147142 Title: CARACTERISATION ET AMELIORATION DE LA QUALITE DE LA BIERE TRADITIONNELLE RWANDAISE « IKIGAGE » FABRIQUEE A BASE DE SORGHO <br/> <br/>Author, co-author: Lyumugabe Loshima, François <br/> <br/>Abstract: Ikigage is a Rwandese traditional beer made from sorghum malt and local plants, mainly Vernonia amygdalina “umubirizi”. However, this beer remains less attractive than Western beers of pils type because of poor hygienic quality, variations of organoleptic quality and limited shelf life. The aim of this work is to characterize ikigage beer in order to improve its hygienic quality and to reduce the organoleptic variations using the local raw materials. The first part of our study shows that ikigage beer marketed in Rwanda is characterized by the presence of Stapylococcus aureus and many micro-organisms of fecal origin (Escherichia coli and fecal streptococci), by the low ethanol content, high total acidity and an important amounts of proteins. The yeasts (Saccharomyces cerevisiae and Issatckenkia orientalis), followed by the lactic acid bacteria (Lactobacillus fermentum and Lactobacillus buchneri), are the predominant microorganisms involved in fermentation of ikigage beer fermentation. Besides, one of the major problems in sorghum beer brewing is the efficient conversion of the starch extracts into fermentable sugars due to the weak activity of β-amylase in sorghum malt. The use of Eleusine coracana “uburo” (Musama variety) malt (30%), associated with mashing decantation procedure, increases the content of sugar fermentable, maltose particularly, in sorghum wort, and consequently ethanol content in the beer. The second part of our study shows that V. amygdalina, known for its antibacterial properties and its bitterness similar to hops, contributes to the production of methyl salycilate, beta-damascenone and many terpenes compounds (δ-3-carene, β-farnesene, farnesol, β-citronellol and linalool), in the sorghum beer “ikigage”. This work reveals also the presence of 14 polyfunctional thiols in beers brewed with ‘non-Western’ raw materials. Among them, the well-known hop constituent 3-methyl-2-buten-1-thiol emerged as a key flavour in the unhopped beers containing V. amygdalina. V. amygdalina also contributes to the production of 1-butanethiol and 4-sulfanyl-4-methyl-2-pentanone in sorghum beer. However, contrary to hops, V. amygdalina addition during boiling also appears to strongly inhibit the production of 2-sulfanylethyl acetate. The third part of our study shows that the use of S. cerevisiae in combination with I. orientalis and L. fermentum as starter allows producing ikigage beer having the GRAS (generally recognized as safe) statute while preserving the organoleptic characteristics similar to those of local traditional beer “ikigage” produced by peasants. http://hdl.handle.net/2268/147073 Title: Contribution à l'étude des amylases du sorgho et leurs utilisations dans la transformation des produits amylacés <br/> <br/>Author, co-author: Ba, Khady <br/> <br/>Abstract: Les amylases sont des enzymes largement utilisées dans le secteur industriel. Elles occupent d'ailleurs une place primordiale dans le marché mondial des enzymes. Les travaux présentés dans ce manuscrit se sont intéressés à la production d’amylases à partir d’une source végétale peu coûteuse et disponible, le sorgho et aux possibilités de les utiliser dans la transformation des produits amylacés. Dans la première partie de l’étude, après avoir caractérisé et malté sept variétés de sorgho blanc sélectionné à l’ISRA de Bambey (Sénégal), la meilleure variété, la F-2-20 (sans tanins, faible teneur en composés phénoliques et bonnes activités amylasiques) a été retenue pour la suite de l’étude. Dans la deuxième partie des travaux, les paramètres physico-chimiques tels que le pH optimum, la température optimale et la thermostabilité des amylases (α et β) du malt ont été caractérisés. Les deux amylases ont le même pH optimal 5,5 et la température optimale est de 65 °C pour l’α-amylase et 55 °C pour la β amylase. Par ailleurs, le gène de la β-amylase a été aussi étudié. Les résultats de la troisième partie des travaux ont montré la capacité des amylases du malt de sorgho à être utilisées dans des processus d’hydrolyse d’amidon (maïs et blé) et farines (blé et manioc). L’ajout d’ions calcium n’améliore pas significativement les rendements d’hydrolyse. Enfin, suite aux résultats obtenus, l’hydrolyse a été réalisée à plus grande échelle afin de produire des dextrines de différents DE. Les dextrines ont été analysées chimiquement et physicochimiquement pour déterminer leur composition en oligosaccharides et leurs propriétés physiques en vue de leur application dans les secteurs agroalimentaires. http://hdl.handle.net/2268/146068 Title: Stress condition during acetic acid fermentation <br/> <br/>Author, co-author: Shafiei, Rasoul; Thonart, Philippe