References of "Hiligsmann, Serge"
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See detailFunctional analysis of hydrogen photoproduction in respiratory-deficient mutants of Chlamydomonas reinhardtii
Lecler, Renaud ULg; Godaux, Damien ULg; Vigeolas, Hélène ULg et al

in International Journal of Hydrogen Energy (2011), 36

In this paper, mitochondrial mutants of Chlamydomonas reinhardtii defective for respiratory complex I (NADH:ubiquinone oxidoreductase), complex III (ubiquinol cytochrome c oxidoreductase) and both ... [more ▼]

In this paper, mitochondrial mutants of Chlamydomonas reinhardtii defective for respiratory complex I (NADH:ubiquinone oxidoreductase), complex III (ubiquinol cytochrome c oxidoreductase) and both complexes I and III were analyzed for H2 photoproduction. Several parameters were followed during the S-deficiency stage and the anaerobic stage leading to H2 photoproduction. At the early aerobic S-deficiency stage, starch and neutral lipids accumulated in all strains but their amount was significantly decreased in mutants compared to wild type. During the H2 photoproduction process, whereas starch content strongly decreased in all strains, neutral lipid amount remained nearly unchanged, suggesting that starch degraded by glycolysis is the preferential substrate for energy production during anaerobiosis. The mutants displayed a decrease in H2 photoproduction correlating to the number of active mitochondrial proton-pumping sites lost in the strains. Our results thus highlight the critical role of oxidative phosphorylation during the first (aerobic) stage of S-starvation when carbon resources are accumulated. [less ▲]

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See detailSynthesis by sol-gel process of visible light sensitive-TiO2 for the degradation of pollutants and microorganisms
Tasseroul, Ludivine ULg; Lambert, Stéphanie ULg; Páez Martínez, Carlos ULg et al

Poster (2011)

Since the discovery of photocatalytic decomposition of water on TiO2 electrodes by Fujishima and Honda [1], heterogenous photocatalysis has been widely studied for environmental applications ... [more ▼]

Since the discovery of photocatalytic decomposition of water on TiO2 electrodes by Fujishima and Honda [1], heterogenous photocatalysis has been widely studied for environmental applications. Photocatalytic processes are new technologies for waste water treatment because new compounds (alkanes, pesticides, dyes, etc.) in effluents are not readily degraded by the conventional treatments [2]. Oxidative processes can completely destroy organic pollutants [3] or microorganisms (bacteria, viruses, fungi, etc.) [4,5]. At this moment, the commercial Degussa P25 is the mostly used photocatalyst. Nevertheless, it requires UV light to be activated, that is why scientists try to activate TiO2 under visible light. The aim of this study is to synthesize photocatalysts activated by visible light and to evaluate their activity for the degradation of pollutants and microorganisms. The sol-gel process allows the direct introduction of visible light sensitive species like porphyrins inside the TiO2 matrix during the synthesis [6]. Two tetracarboxyphenyl porphyrins are synthesized for the sensitization of TiO2 to visible light : the metal free tetracarboxyphenyl porphyrin and the nickel tetracarboxyphenyl porphyrin. These porphyrins are characterized by 1H NMR, FT-IR and UV/Vis spectroscopies. They are introduced during the sol-gel synthesis of TiO2 matrix. Diffuse reflectance and FT-IR spectroscopies are used to ensure that porphyrins are incorporated inside the matrix of TiO2. Indeed, characteristic porphyrins peaks appear on spectra. The cristallinity and specific surfaces of catalysts are also determined by XRD and nitrogen adsorption-desorption measurements respectively. The depolluting efficiency of photocatalysts is evaluated for the degradation in water of p-nitrophenol, which is listed as one of the 114 organic pollutants by the Environmental Protection Agency in the US. After 6 h under visible light, 40 % of p-nitrophenol are degraded with some catalysts. The activity is influenced by i) the presence of porphyrins : the photoactivity increases with the amount of porphyrins ; ii) the nature of porphyrins : nickel porphyrins are more active than free metal porphyrins ; and iii) the crystallinity of catalysts : amorphous catalysts are less active than crystallized samples. The photocatalysts with the highest degradation rating of dyes will be selected for the degradation in water of Escherichia coli and Lactobacillus acidophilus. [1] A. Fujishima, K. Honda, Nature 238, 37-38 (1972) [2] P. Gogate, A. Pandit, Advances in Environmental Research 8, 501-551 (2004). [3] D. Chen, A. Ray, Water Research 32, 3223-3234 (1998) [4] R. Watts, S. Kong, M. Orr, G. Miller, B. Henry, Water Research 29, 95-100 (1995). [5] J. Hong, M. Otaki, Journal of Bioscience and Bioengineering 101, 185-189 (2006). [6] C. Wang, J. Li, G. Mele, G.M. Yang, F.-X. Zhang, L. Palmisano, G. Vasapollo, Applied catalysis 78, 218-226 (2007). [less ▲]

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See detailComparative study of biological hydrogen production by pure strains and consortia of facultative and strict anaerobic bacteria
Hiligsmann, Serge ULg; Masset, Julien ULg; Hamilton, Christopher ULg et al

in Bioresource Technology (2011), 102

In this paper, a simple and rapid method was developed in order to assess in comparative tests the production of binary biogas mixtures containing CO2 and another gaseous compound such as hydrogen or ... [more ▼]

In this paper, a simple and rapid method was developed in order to assess in comparative tests the production of binary biogas mixtures containing CO2 and another gaseous compound such as hydrogen or methane. This method was validated and experimented for the characterisation of the biochemical hydrogen potential of different pure strains and mixed cultures of hydrogen-producing bacteria (HPB) growing on glucose. The experimental results compared the hydrogen production yield of 19 different pure strains and sludges : facultative and strict anaerobic HPB strains along with anaerobic digester sludges thermally pre-treated or not. Significant yields variations were recorded even between different strains of the same species by i.e. about 20% for three Clostridium butyricum strains. The pure Clostridium butyricum and pasteurianum strains achieved the highest yields i.e. up to 1,36 mol H2/mol glucose compared to the yields achieved by the sludges and the tested Escherichia and Citrobacter strains. [less ▲]

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See detailLa biométhanisation : technologies de choix
Hiligsmann, Serge ULg

Conference (2010, November 23)

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See detailInvestigation of anaerobic digestion in a two-stage bioprocess producing hydrogen and methane
Hiligsmann, Serge ULg; Hamilton, Christopher ULg; Beckers, Laurent ULg et al

Conference (2010, November 17)

Hydrogen has received wide attention in the last decades as a clean energy vector. The major advantage of energy generation from hydrogen is the near-zero carbon emissions, since the utilization of ... [more ▼]

Hydrogen has received wide attention in the last decades as a clean energy vector. The major advantage of energy generation from hydrogen is the near-zero carbon emissions, since the utilization of hydrogen, either via combustion or via fuel cells, results in pure water. Recently, there has been increasing interest on the biological production of hydrogen gas from renewable biomass such as carbohydrates from agriculture or agro-food industries. This specific anaerobic digestion is called dark fermentation and is involved in the classic anaerobic digestion producing methane. Indeed, in a two-step process, i.e. when acido- and aceto-genesis are carried out in a different bioreactor than methanogenesis, it is feasible to generate separated biogas flows containing either H2 or CH4 depending on specific operating parameters. This paper deals with the comparison of the first stage performances whether operated in optimum conditions for H2 production with a mixed culture or a pure Clostridium butyricum strain. Hydrogen yields of about 1.75 and 2.3 mol H2/mol glucose were achieved respectively. The metabolites, mainly acetate and butyrate, contained in the spent medium were efficiently converted to methane in a second anaerobic digester with a methane yield of about 170 ml/g COD initially fed in the first stage. [less ▲]

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See detail(Functionnal) analysis of hydrogen production in Chlamydomonas reinhardtii mitochondrial mutants
Lecler, Renaud ULg; Godaux, Damien ULg; Hamilton, Christopher ULg et al

Poster (2010, June 27)

Mitochondrial Chlamydomonas mutants for respiratory complexes present a decreased dark respiration and apparent yield of photosynthetic linear electron flow. They accumulate reducing power such as NAD(P)H ... [more ▼]

Mitochondrial Chlamydomonas mutants for respiratory complexes present a decreased dark respiration and apparent yield of photosynthetic linear electron flow. They accumulate reducing power such as NAD(P)H and show lower levels of ATP. Under restrictive conditions, like sulfur depletion and anoxia, Chlamydomonas is able to produce hydrogen towards the activation of a chloroplatic O2-sensitive Fe-hydrogenase which catalyses the reduction of electrons to H2. In this study we used an adapted Melis protocol to analyse hydrogen evolution of mitochondrial mutants. For this aim a simple-flask system was built with gaz collecting tubes. A parallel flask was used for GC analyses. [less ▲]

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See detailEffect of pH on glucose and starch fermentation in batch and sequenced-batch mode with a recently isolated strain of hydrogen-producing Clostridium butyricum CWBI1009
Masset, Julien ULg; Hiligsmann, Serge ULg; Hamilton, Christopher ULg et al

in International Journal of Hydrogen Energy (2010), 35(8), 3371-3378

This paper reports investigations carried out to determine the optimum culture conditions for the production of hydrogen with a recently isolated strain Clostridium butyricum CWBI1009. The production ... [more ▼]

This paper reports investigations carried out to determine the optimum culture conditions for the production of hydrogen with a recently isolated strain Clostridium butyricum CWBI1009. The production rates and yields were investigated at 30 °C in a 2.3 l bioreactor operated in batch and sequenced-batch mode using glucose and starch as substrates. In order to study the precise effect of a stable pH on hydrogen production, and the metabolite pathway involved, cultures were conducted with pH controlled at different levels ranging from 4.7 to 7.3 (maximum range of 0.15 pH unit around the pH level). For glucose the maximum yield (1.7 mol H2 mol-1 glucose) was measured when the pH was maintained at 5.2. The acetate and butyrate yields were 0.35 mol acetate mol-1 glucose and 0.6 mol butyrate mol-1 glucose. For starch a maximum yield of 2.0 mol H2 mol-1 hexose, and a maximum production rate of 15 mol H2 mol-1 hexose h-1 were obtained at pH 5.6 when the acetate and butyrate yields were 0.47 mol acetate mol-1 hexose and 0.67 mol butyrate mol-1 hexose. [less ▲]

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See detailFermentative hydrogen production by Clostridium butyricum CWBI1009 and Citrobacter freundii CWBI952 in pure and mixed cultures
Beckers, Laurent ULg; Hiligsmann, Serge ULg; Hamilton, Christopher ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14(S2), 541-548

This paper investigates the biohydrogen production by two mesophilic strains, a strict anaerobe (Clostridium butyricum CWBI1009) and a facultative anaerobe (Citrobacter freundii CWBI952). They were ... [more ▼]

This paper investigates the biohydrogen production by two mesophilic strains, a strict anaerobe (Clostridium butyricum CWBI1009) and a facultative anaerobe (Citrobacter freundii CWBI952). They were cultured in pure and mixed cultures in serum bottles with five different carbon sources. The hydrogen yields of pure C. freundii cultures ranged from 0.09 molH2.molhexose-1 (with sucrose) to 0.24 molH2.molhexose-1 (with glucose). Higher yields were obtained by the pure cultures of Cl. butyricum ranging from 0.44 molH2.molhexose-1 (with sucrose) to 0.69 molH2.molhexose-1 (with lactose). This strain also fermented starch whereas C. freundii did not. However, it consumed the other substrates faster and produced hydrogen earlier than Cl. butyricum. This ability has been used to promote the growth conditions of Cl. butyricum in co-culture with C. freundii, since Cl. butyricum is extremely sensitive to the presence of oxygen which strongly inhibits H2 production. This approach could avoid the addition of any expensive reducing agents in the culture media such as L-cysteine since C. freundii consumes the residual oxygen. Thereafter, co-cultures with glucose and starch were investigated: hydrogen yields decreased from 0.53 molH2.molhexose-1 for pure Cl. butyricum cultures to 0.38 molH2.molhexose -1 for mixed culture with glucose but slightly increased with starch (respectively 0.69 and 0.73 molH2.molhexose-1). After 48 h of fermentation, metabolites analysis confirmed with microbial observation, revealed that the cell concentration of C. freundii dramatically decreased or was strongly inhibited by the development of Cl. butyricum. [less ▲]

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See detailOptimisation of culture conditions for biological hydrogen production by Citrobacter freundii CWBI952 in batch, sequenced-batch and semicontinuous operating mode
Hamilton, Christopher ULg; Hiligsmann, Serge ULg; Beckers, Laurent ULg et al

in International Journal of Hydrogen Energy (2010), 35

Investigations were carried out to determine the effect of the pH, the nitrogen source, iron and the dilution rate (h 1) on fermentative hydrogen production from glucose by the newly isolated strain ... [more ▼]

Investigations were carried out to determine the effect of the pH, the nitrogen source, iron and the dilution rate (h 1) on fermentative hydrogen production from glucose by the newly isolated strain Citrobacter freundii CWBI952. The hydrogen production rate (HPR), hydrogen yield, biomass and soluble metabolites were monitored at 30 C in 100 mL serum bottles and in a 2.3 L bioreactor operated in batch, sequenced-batch and semicontinuous mode. The results indicate that hydrogen production activity, formate biosynthesis and glucose intake rates are very sensitive to the culture pH, and that additional formate bioconversion and production of hydrogen with lower biomass yields can be obtained at pH 5.9. In a further series of cultures casein peptone was replaced by (NH4)2SO4, a low cost alternative nitrogen source. The ammonia-based substitute was found to be suitable for H2 production when a concentration of 0.045 g/L FeSO4 was provided. Optimal overall performances (ca. an HPR of 33.2 mL H2/L h and a yield of 0:83 molH2 =molglucose) were obtained in the semicontinuous culture applying the previously optimized parameters for pH, nitrogen, and iron with a dilution rate of 0.012 h 1 and degassing of biogas by N2 at a 28 mL/min flow rate. [less ▲]

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See detailApplication of molecular techniques to monitor the evolution of bacterial consortia composed of Clostridium sp. in a hydrogen producing bioreactor
Calusinska, Magdalena ULg; Savichtcheva, Olga; Joris, Bernard ULg et al

Poster (2009, December 11)

Our current dependence on fossil fuels as the primary energy source contributes to global climate change, environmental degradation and health problems. Hydrogen offers a tremendous potential as a clean ... [more ▼]

Our current dependence on fossil fuels as the primary energy source contributes to global climate change, environmental degradation and health problems. Hydrogen offers a tremendous potential as a clean, renewable energy currency and it is compatible with electrochemical and combustion processes for energy conversion without producing carbon – based emissions. Many microorganisms, especially photosynthetic as well as facultative and anaerobic bacteria have been reported to produce large amounts of hydrogen from soluble and insoluble biomass. Clostridia, being obligate anaerobes, are capable of biogas production during ‘dark fermentation’ of a wide range of carbohydrates. In this ARC project, entitled Micro – H2 we have focused on a new direction in bio – hydrogen production systems which is the use of mixed cultures of microorganisms (consortia). We expect that the combination of complementary metabolisms could significantly increase the efficiencies of mixed systems compared to monocultures. However, a few fundamental studies need to be carried out in order to investigate and improve the stability of microbial populations involved in the processes. It is now recognised that molecular microbial ecology tools provide the scientific basis to monitor the processes used in environmental biotechnology. To characterize the diversity of bacterial communities, quantitative techniques such as Real – Time Quantitative PCR and FISH (Fluorescence in situ hybridization) and semi – quantitative DGGE (Denaturing Gradient Gel Electrophoresis) have been optimized and applied on different bioreactor samples. This approach enabled for the temporal monitoring of the evolution of bacterial consortia, both in terms of species dominance and their metabolic activity. Molecular analysis of bacterial consortia allowed for careful examination of interactions between different bacterial species within a consortium, which is crucial in the stabilization of the hydrogen production process. [less ▲]

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See detailBiohydrogen production from anaerobic digestion of carbohydrate organic matter.
Hiligsmann, Serge ULg; Masset, Julien ULg; Beckers, Laurent ULg et al

Poster (2008, December 16)

Hydrogen has received wide attention in the last decade as a clean energy vector. The major advantage of energy from hydrogen is the zero carbon emissions, since the utilization of hydrogen, either via ... [more ▼]

Hydrogen has received wide attention in the last decade as a clean energy vector. The major advantage of energy from hydrogen is the zero carbon emissions, since the utilization of hydrogen, either via combustion or via fuel cells, results in pure water. At industrial scale, steam reformation of methane is currently the major hydrogen producing process. However recently, increasing interest has been paid on biological production of hydrogen gas. Indeed, biohydrogen generation from renewable biomass would reduce dependence on fossil fuel, decrease the carbon dioxide emissions and produce usable bioenergy. Biological production of hydrogen using anaerobic bacteria is an exciting and promising new area of technology development that offers the potential production of usable hydrogen from a variety of renewable resources such as carbohydrates from agriculture or agro-food industries. This biological system is called dark fermentation and the most interesting bacteria strains are Clostridium sp. The investigations carried out at CWBI involve selection and characterization of bacteria strains, optimization of the biotechnological process and design of highly efficient bioreactors. [less ▲]

Detailed reference viewed: 49 (8 ULg)