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See detailField bordering flower strips as source of lipids
Paul, Aman ULg; Danthine, Sabine ULg; Stephanie, Heuskin et al

Poster (2014, February 07)

Field bordering flower strips not just only improves the biodiversity but also serves as a source of beneficial compounds. Some of the plants in these strips can be really interesting source of lipids ... [more ▼]

Field bordering flower strips not just only improves the biodiversity but also serves as a source of beneficial compounds. Some of the plants in these strips can be really interesting source of lipids, the oils extracted from their seeds can be important for food, pharmaceutical and cosmetics industries. Six species of plants from flowering strips in Belgium were investigated for their seed oil content. The oil from seeds was extracted by cold extraction technique using chloroform/methanol in 2:1 ratio as solvent. Oil extraction from seeds of Red Clover (Trifolium pratense), Rough Hawkbit (Leontodon hispidus), Cow Parsley (Anthriscus sylvestris), St John’s Wort (Hypericum perforatum), Common Yarrow (Achillea millefollium) and Birdsfoot Trefoil (Lotus corniculatus) plant species was done on wet weight which came out to be 7.89±0.11%, 11.86±0.07%, 14.78±0.31%, 24.20±0.02%, 20.08±0.15% and 7.04±0.12% respectively. The physicochemical properties of the extracted oils were analyzed. Some of these oils can be of great commercial value. [less ▲]

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See detailBiofilms from entomopathogenic fungi in mosquito control
Bawin, Thomas ULg; Boukraa, Slimane; Seye, Fawrou et al

Poster (2014, February 07)

Mosquitoes (Diptera: Culicidae) are zoonotic vectors of medical and veterinary importance. As part of an integrated vector control, metabolites secreted by entomopathogenic fungi could be developed as ... [more ▼]

Mosquitoes (Diptera: Culicidae) are zoonotic vectors of medical and veterinary importance. As part of an integrated vector control, metabolites secreted by entomopathogenic fungi could be developed as biopesticides. In this context, filamentous microorganisms growing on a support as biofilm in a liquid medium would offer several advantages in bioreactor regarding performances and metabolites recovery. The production of toxic metabolites by an entomopathogenic fungus Aspergillus flavus in such conditions was assessed. Three initial inoculum levels, i.e. 10^1, 10^3 and 10^6 spores/ml of PYG medium, have been tested in shake flask with or without support. Toxicity tests were performed on Culex quinquefasciatus larvae using dilutions of 1, 2, 4, 6, 8 and 10% of liquid cultures. The results indicated that A. flavus tends to form pellets in submerged culture; the size and the amount of pellets was affected by the initial inoculum level of spores. Under similar conditions, the filaments fixed on a support and didn’t appear in free form in the liquid. Toxicity tests revealed differences between both free and fixed forms. All combined conditions, LC50s ranging up to dilutions of 2.2 and 4.8% were observed within 48 hours. Secretomes could be compared between these culture conditions by proteomic and metabolomic approaches. [less ▲]

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See detailIncrease in Soil Macroporosity managed with Winter Ploughing - a preliminary results
Parvin, Nargish ULg; Chelin, Marie ULg; Hiel, Marie-Pierre ULg et al

Poster (2014, February 07)

Measurement of soil water retention capacity by the conventional pressure plate technique always gives a substantial view of soil porosity distribution. The structural orientation is observed in the ... [more ▼]

Measurement of soil water retention capacity by the conventional pressure plate technique always gives a substantial view of soil porosity distribution. The structural orientation is observed in the beginning (higher water retention at 9.8 to 98 hPa water head pressure indicates greater proportion of macroporosity) of the soil moisture characteristic curve obtained from the water retention measurement. Since, tillage practices generally increase soil porosity, the correlation between soil hydraulics and porosity distribution would expect to be different for different tillage systems. In general, macroporosity increase with the adoption of conservative tillage or no tillage system but the changes can be varied with the seasonal variation. In our study, winter ploughing retains more water at the range of 9.8 to 98 hPa than Strip tillage, No-till residues in and No-till residues out. So, we can conclude that there is certainly increase in macroporosity in ploughing than other conservation practices of reduced tillage and no tillage. [less ▲]

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See detailDevelopment of formulated elicitors to control bioagressors of wheat: which interests?
Le Mire, Géraldine ULg; Deleu, Magali ULg; Ongena, Marc ULg et al

Poster (2014, February 07)

Crop plants are constantly exposed to a wide range of environmental stresses that can cause major productivity loss. Fungicide treatments are the most efficient disease control methods used up to now ... [more ▼]

Crop plants are constantly exposed to a wide range of environmental stresses that can cause major productivity loss. Fungicide treatments are the most efficient disease control methods used up to now. However, the environmental and health issues caused by these chemicals make it urgent to develop safer methods for pathogen control. In the optic of a sustainable agriculture, several biocontrol tools have been developed during the last decades. Elicitors are increasingly subject to research as interesting alternatives to phytosanitary products. Yet, few efficient formulations exist on the market, and no product has been designed specifically to protect wheat crops. This study will thus focus on the the manipulation of host natural defenses through the use of elicitors as a preventive treatment against major wheat diseases such as Septoria tritici, Fusarium graminearum and Fusarium culmorum. [less ▲]

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See detailBiofilter in aquaponics
Delaide, Boris ULg; Lambrechts, Paul Emile ULg; Willaert, Jean-François ULg et al

Poster (2014, February 07)

Aquaponics is a combination of aquaculture (fish farming) and hydroponics (horticulture). In this concept, the fish faeces and excreted ammonia are partially transformed into soluble nutrients which then ... [more ▼]

Aquaponics is a combination of aquaculture (fish farming) and hydroponics (horticulture). In this concept, the fish faeces and excreted ammonia are partially transformed into soluble nutrients which then are available for plants. Wastewater from aquaculture is filtrated by plants and return to the fish tank in a loop cycle. This strongly reduces the use of water and increases the economic efficiency with an additional production of plant, e.g. vegetables. From the hydroponics view, this combination allows important decreases in chemical nutrients use for plant grow. A central part of this system is the biofilter. The microorganisms that colonize it are essential to process the fish waste into soluble nutrients easily assimilated by plants. During this process, nitrifying bacteria convert free ammonia into nitrite and then nitrate. The first objective of this research will concern the identification and isolation of the main microorganism species involved by the dilution plating and metagenomics technics. The optimal conditions to process the fish waste will be determined for such microorganism. The efficiency of nitrite and nitrate production by these micro-organisms will be tested in different conditions (T°, pH, O2, water flow, support, etc..) in vitro at the lab scale and in aquaponics prototypes. [less ▲]

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See detailEstimating daily yield and content of major fatty acids from single milking
Arnould, Valérie ULg; Reding, Romain; Delvaux, Charles et al

Poster (2014, February 07)

Reducing the frequency of milk recording and the number of recorded samples per test-day could be a solution in order to reduce costs of official milk recording. However, fewer samples lead to a decrease ... [more ▼]

Reducing the frequency of milk recording and the number of recorded samples per test-day could be a solution in order to reduce costs of official milk recording. However, fewer samples lead to a decrease in the accuracy of predicted daily yields. Unfortunately, the current published equations use the milking interval that is often not available and/or reliable in practice. The first objective of this study was to propose models using easily available traits. Therefore the milking interval was replaced by a combination of data easily recorded by milk recording. The second objective of this study was to enlarge the previous investigations to milk fatty acids (FA) in order to propose a practical method for estimating accurate daily milk, fat and major FA yields from single milking. The fit goodness of proposed models was evaluated based on the correlation values between the estimated and observed daily yields in addition to the calculation of the mean square error. Obtained results are promising. Correlation values were comprised between 96.4% and 97.6% when daily yield were estimated from morning milking, and from 96.9% to 98.3% when daily yield were estimated from evening milking. The combination of records related to lactation stage, month of test, milk yield, and fat could replace the milking interval effect. Because of their simplicity, proposed models would be easy to implement. [less ▲]

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See detailA diachronic analysis of the dynamic of two cities: Kisangani and Lubumbashi (Democratic Republic of Congo): How do the extension and/or of the densification of these cities impact the urban internal and peripheral ecosystems?
Andre, Marie ULg; Mahy, Grégory ULg; Lejeune, Philippe ULg et al

Poster (2014, February 07)

The dynamics of two cities between two years (2002 and 2010 for Kisangani; 2002 and 2008 for Lubumbashi, both part of the Democratic Republic of Congo) have been examined in order to estimate how their ... [more ▼]

The dynamics of two cities between two years (2002 and 2010 for Kisangani; 2002 and 2008 for Lubumbashi, both part of the Democratic Republic of Congo) have been examined in order to estimate how their extension and/or of the densification have impacted the urban internal and peripheral ecosystems. This study singularizes itself from the subjective ones by its quantified and objective approach based on landscape ecology. This discipline assumes that the landscape pattern description is important because, according to its central hypothesis called “pattern-process paradigm”, the ecological processes influence landscape structure and vice versa. Composition metrics, which are commonly used in landscape ecology, describe the pattern among other things in quantifying the presence and the number of patches from the various classes within the landscape. For each city two SPOT 5 images were classified with a oriented-object supervised approach; then built area proportion index, a composition landscape metric, has been evaluated in order to 1) identify the extent of each area (urban, suburban, rural) within the urban-rural gradient, 2) quantify the dynamic of the different areas in the urban-rural gradient during the last decade and 3) quantify the effect of a decade of urban and suburban growth on ecosystems. The similarities and differences between these cities, relevance and gaps in the method have then been identified and discussed. [less ▲]

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See detailAnd the winner is ... When =f and pAj=f play hide-and-seek
Winand, Jean ULg

Conference (2014, February 07)

Detailed reference viewed: 26 (5 ULg)
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See detailThree aspects, One concept: Agroecology. Agroecological practices and human interactions for a new approach for science. An example at the Univeristy of Liege.
Hatt, Séverin ULg; Artru, Sidonie ULg; Boeraeve, Fanny et al

Poster (2014, February 07)

Critics are raising about conventional farming and its consequences on biodiversity, human health and society. As alternatives, novel models for agriculture are proposed, and among them Agroecology. Quite ... [more ▼]

Critics are raising about conventional farming and its consequences on biodiversity, human health and society. As alternatives, novel models for agriculture are proposed, and among them Agroecology. Quite often, Agroecology is seen as the application of ecological knowledge to the agricultural production. Indeed, this helps to develop more ecological farming practices favoring biodiversity to provide ecosystem services at multiple scales. Agroecology goes further in considering that the agricultural production is integrated in a food system guided by human interactions. This latter one takes into account socio-economic and political dimensions to develop new production systems. Doing so, it assures food security worldwide while preserving resources for future generations. Facing these ambitious objectives, academics are invited to elaborate a new approach for science in developing participatory and action-oriented approaches as well as multidisciplinarity. AgricultureIsLife is a research platform built up at the University of Liège (ULg). In 2013, 40 researchers (including 18 young researchers) from 16 research units of ULg were working in a multidisciplinary approach. About twenty research topics have been divided in four research axes of which objectives are to develop a more sustainable agriculture. The platform has the ambition to discuss its results to a large comity gathering the actors of the agricultural development. The aim of our work is firstly to present Agrocology as a concept made of three interrelated aspects. To illustrate it, the organization and objectives of the research platform AgricultureIsLife will be discussed in a second part. [less ▲]

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See detailPaints based on renewable materials
Olive, Gilles ULg; Richel, Aurore ULg

in BOOK OF SHORT ABSTRACTS - POSTER PRESENTATIONS 19TH NATIONAL SYMPOSIUM ON APPLIED BIOLOGICAL SCIENCES (2014, February 07)

Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming ... [more ▼]

Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming material, diluted in solvents. Pigments are solid particles, used to give opacity and/or color. Today almost all pigments have a synthetic origin. The fillers are often natural compounds. Unlike pigments, fillers have low opacity and are colorless. These very cheap products achieve the required solid content under satisfactory economic conditions. Resins used in paints have the property of forming a continuous solid (hard or flexible) film under specific conditions. They are often called “resins”. They can be solid or liquid at room temperature. The solvents are used to control the viscosity of the paint in order to facilitate its production and application. The solvents used are volatile compounds. Additives are minor compounds (a few percent), whose function is to either promote or prevent some developments of the product. For example, surfactants improve the homogeneity of the dispersion. Some additives protect the film against mold or ultraviolet radiation, or against the formation of free radicals under the action of sunlight. Since the end of the 18th century most of those paints are petroleum-based. But the near disappearance of the petroleum causes a renewed interest in bio-based preparations. In this communication, we present an overview of bio-based alternatives. [less ▲]

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See detailOld inks: pigments extracted from plants
Despy, Jessica; Wymeersch, Noémie; Bouchat, Isabelle et al

in BOOK OF SHORT ABSTRACTS - POSTER PRESENTATIONS 19TH NATIONAL SYMPOSIUM ON APPLIED BIOLOGICAL SCIENCES (2014, February 07)

Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A ... [more ▼]

Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A significant example of this is the Cosquer cave (-19,000 to -27,000 years) located near Marseilles. Pigments and dyes can be classified into two broad categories and five families: natural pigments and dyes and those called artificial. The first one of these five families includes the mineral pigments. Among these we can find the clays (yellow ochre, red ochre, green clay, brown clay) and the stones like lapis lazuli (blue). The second and third families gather the organic dyes and pigments. Those that have vegetal origins like indigo (blue) and madder (red) compose the second family and those that have animal origins like cochineal (red) and kermes dyers (carmine) form the third family. One family includes pigments and dyes stemming from chemical reactions such as verdigris or red lead (family 4) and the other one is made of the miscellaneous inks such as iron-gall type who are vegetal and mineral one (family 5). All these pigments, although they have been used for centuries, have been replaced by synthetic dyes from the oil industry at the end of the 19th century. Indeed, they have the advantage of reproducibility of the properties unlike natural pigments. But the scarcity of oil causes a renewed interest in natural preparations. We report the extraction of pigments from plants. [less ▲]

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See detailBiodiversity and ecosystem services: think functional!
Uyttenbroeck, Roel ULg; Hatt, Séverin ULg; Paul, Aman ULg et al

Poster (2014, February 07)

During the last years, several studies and reviews have considered the relation between biodiversity and ecosystem functioning or the provision of ecosystem services. Many studies found that plant ... [more ▼]

During the last years, several studies and reviews have considered the relation between biodiversity and ecosystem functioning or the provision of ecosystem services. Many studies found that plant functional traits and plant functional diversity (FD) are key drivers in this relation in terrestrial ecosystems. Researchers used different methods to obtain a gradient in plant FD to examine the effect on ecosystem services, going from observational studies of natural communities to synthetic assemblages. Furthermore, different methods exist to quantify plant FD going from simple functional trait richness to indices, distance-based frameworks and the division into FD components. In the AgricultureIsLife project, we set up a field experiment aiming to examine the biodiversity – ecosystem service relation in agricultural context. The experiment consists of perennial wildflower strips with different plant functional diversities in an arable field with conventional crop production. The wildflower strips were sown as synthetic assemblages but are subject to natural succession during the following years. We monitor the evolution of FD from the sowing to the establishment of a typical wildflower strip using Rhao’s quadratic entropy index to quantify FD. In addition, the flower strips will be monitored for four ecosystem services they are expected to provide: pollination, pest control, biodiversity support and provision of valuable compounds. [less ▲]

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See detailLa malédiction de Cassandre. Histoire d'une plateforme distribuée d'analyse qualitative de textes et d'images
Lejeune, Christophe ULg

Scientific conference (2014, February 07)

Le logciel Cassandre fait partie de la plateforme Hypertopic d'annotation collaborative de textes et d'images. Du point de vue de la recherche en informatique, le développement de cette plateforme s ... [more ▼]

Le logciel Cassandre fait partie de la plateforme Hypertopic d'annotation collaborative de textes et d'images. Du point de vue de la recherche en informatique, le développement de cette plateforme s'insère dans le courant du Web socio-sémantique. Du point de vue des sciences humaines, la plateforme fournit des outils de recherche qualitative. Christophe Lejeune fait le récit de son expérience de développement (de 2005 à aujourd'hui). Ce faisant, il illustre des notions abordées dans les séances précédentes, telles que les questions de gestionnaire de versions, les services Web RESTful, les centres de calcul, les nuages, les collaborations inter-universitaires, les communautés Open Source et la relation avec les utilisateurs. [less ▲]

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See detailContribution to the study of alliinase, the active principle of garlic
DETHIER, Bérénice ULg; Ponchaux, Julien; Laloux, Morgan et al

Poster (2014, February 07)

Alliinase is a crucial enzyme in the Allium genus. The conversion of its substrates, cysteine sulfoxides, into volatile thiosulfinates is an important mechanism in the defence of the plant. It also ... [more ▼]

Alliinase is a crucial enzyme in the Allium genus. The conversion of its substrates, cysteine sulfoxides, into volatile thiosulfinates is an important mechanism in the defence of the plant. It also provides the typical pungent flavour of garlic. As a matter of fact, the thiosulfinates decompose in a range of organosulfur compounds (OSC) known for their biological activities (antioxidant, anticancer, anti-diabetes properties, etc.). The environment of the decomposition of the thiosulfinates determines the type and amount of products released. A deeper knowledge of the conditions that form each OSC could help us in the preparation of garlic-based nutraceutics in the perspective of healthier food consumption. This study aims to improve the extraction and purification the enzyme alliinase in order to perform the reaction between the enzyme and its substrates and assess the potentialities of garlic preparations. Three methods have been applied to evaluate the efficiency of the extractions and purifications of the enzyme. A first idea of the purity of the enzyme is given by an electrophoresis separation of each sample on a polyacrylamide gel (SDS-PAGE). The protein content is then measured by UV-vis spectrometry with Lowry-Folin reagent for the coloration and BSA as an external standard. Finally, the specific activity is assessed by an indirect measure of the pyruvate (released as a co-product): the addition of NADH and lactate dehydrogenase turns the pyruvate in lactate, and the disappearance of NADH is measured by UV-vis spectrometry at 340 nm. The extraction of the enzyme from garlic was performed either by PEG 8000 precipitation or by ammonium sulphate precipitation. Two purifications were tested: affinity chromatography (on ConA) and size-exclusion chromatography. The combination of the ammonium sulphate process with the ConA chromatography provided the purest enzyme, with the best activity but a lower yield than the size-exclusion process. Finally the stability of the enzyme has been assessed at 4, -20 and -80 °C, showing that the enzyme could be kept at -80 °C for over 4 months without deterioration, while activity loss was observed at higher temperature. [less ▲]

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See detailIntegrated farming systems in Kinshasa (DRC) Diversity of agricultural practices
Mafwila Kinkela, Patrick ULg; Bindelle, Jérôme ULg; WILLEMS, E, Emilie et al

Poster (2014, February 07)

In Kinshasa in the Democratic Republic of Congo, integrated farming of livestock and fish farming is little documented while it is an interesting way of ecological intensification systems. After ... [more ▼]

In Kinshasa in the Democratic Republic of Congo, integrated farming of livestock and fish farming is little documented while it is an interesting way of ecological intensification systems. After identifying the density of fish ponds in the territory of the city using satellite images, about 200 farms with at least one pond and located in 2 in peri-urban and rural areas were surveyed to characterize the practical integration of the agricultural system. The preliminary results in one of the valleys indicate that the practice of agriculture in synergy with the pig and fish farming is a common practice although flow of components are still insufficiently integrated and some of them are not optimized . The fish - pig farming associations with or without vegetable production are 44 % of the sample. The identification of flow on farms showed that the manure of pigs is mainly used for crops (51%) or sold (28%), while a small part is used to fertilize the ponds. This may be explained by the predominant share of income (67%) devoted to vegetable production while sludge of ponds is rarely used to fertilize area of vegetable production. Residues of vegetable crops are rarely used to feed pigs and fish because of their limited availability. Feeding pigs and fish is based primarily on agro-industrial by-products such as wheat bran (81%) and the spent brewery grains (62%) and forages (62%). The presentation will analyze the results obtained in the three sites visited and outline opportunities for improvement. [less ▲]

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See detailIs the noxious Ambrosia artemisiifolia L. going to invade Belgium?
Ortmans, William ULg; Chauvel, Bruno; Mahy, Grégory ULg et al

Poster (2014, February 07)

Ambrosia artemisiifolia L. is an invasive species from North America, causing a health crisis in Europe due to its highly allergenic pollen. In France, there is a zone where the A. artemisiifolia ... [more ▼]

Ambrosia artemisiifolia L. is an invasive species from North America, causing a health crisis in Europe due to its highly allergenic pollen. In France, there is a zone where the A. artemisiifolia populations are naturalized and invasive. Outside this area, populations are more rare and do not seem to expand. We tested if the performances of A. artemisiifolia are varying with competition level, and among geographical zones. The results show that populations from Belgium and Netherlands are not less efficient than invasive populations for the measured traits. [less ▲]

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See detailUse of GC-MS in SIM-Scan mode for a selective quantification of polluting volatile organic compounds (VOC) in food industries
Eloundou Mballa, Pierre ULg; DETHIER, Bérénice ULg; Fauconnier, Marie-Laure ULg

Poster (2014, February 07)

The control of atmospheric emission discharges by food industries is classically achieved in two phases. The first one consists of sampling the target atmosphere followed by concentrating the volatile ... [more ▼]

The control of atmospheric emission discharges by food industries is classically achieved in two phases. The first one consists of sampling the target atmosphere followed by concentrating the volatile organic compounds (VOC) contained in a defined volume of this atmosphere on an adsorbing agent. These compounds are then thermally desorbed (TD) or desorbed with a solvent. In the second phase, the gas phase chromatogram (GC) will be coupled with mass spectrometry (MS) or flame ionization detector (FID) for compounds analysis. Quantitative analysis are usually achieved with solvent desorption followed by GC-FID. However, this mode imposes the dilution of the sample by a solvent and consequently may cause high detection thresholds as well as important matrix effect and possible interferences due to chemical reactions between analytes and the solvent. Besides, a preliminary qualitative analysis (GC-MS identification) is necessary. Combining TD-GC-MS allows very low detection thresholds to be reached, and the matrix effect and the interferences caused by products of the reactions between analytes and the solvent to be eliminated. The use of this combination in selected ion monitoring (SIM) mode allows targeting analytes via their characteristic ions, increasing their sensitivity and repeatability insuring more accuracy for simultaneous qualitative and quantitative analysis. This technique was experimented for seeking VOC in the atmosphere around food industries. [less ▲]

Detailed reference viewed: 29 (7 ULg)
Peer Reviewed
See detailInteractions of a potential plant elicitor mannolipid with plant model membranes
Polo Lozano, Damien ULg; Lins, Laurence ULg; Ongena, Marc ULg et al

Poster (2014, February 07)

The use of chemical pesticides causes problems for human health and environment. In this context, there is an increasing interest for alternative products such as biopesticides. Among them, elicitors act ... [more ▼]

The use of chemical pesticides causes problems for human health and environment. In this context, there is an increasing interest for alternative products such as biopesticides. Among them, elicitors act on the plants by inducing systemic resistance against diseases caused by fungal, viral, bacterial agents and insects. The target of the elicitors is supposed to be the plant plasma membranes (PPM). The main mechanisms of interaction of many elicitors involve proteic receptors but lipid-based elicitors (LBE) may preferably interact with the lipidic fractions of PPM. However there is no detailed information at the molecular level on the PPM-LBE interactions. Our work is focused on a original synthetic LBE composed of a mannoside linked to a myristic acid. It has potential elicitor activities as shown by the assays on tobacco root cells. These activities could be related to its interaction with the lipidic phase of PPM. Since PPM are complex entities, the analyses of the PPM- molecule interactions are quite difficult. In this context, these interactions were carried out using biomimetic membranes of PPM such as Langmuir monolayers and multilayers. The effects of our molecule on these membranar systems were investigated by biophysical and in silico approaches. [less ▲]

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See detailEffect of encapsulated nanoparticles on thermophillic anaerobic digestion
Al-Ahmad, Alaa Eddin ULg; Hiligsmann, Serge ULg; Lambert, Stéphanie ULg et al

Poster (2014, February 07)

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 ... [more ▼]

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 ▲]

Detailed reference viewed: 29 (6 ULg)