References of "Masset, Julien"
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See detailLa production de biohydrogène à partir de substrats carbohydratés : état de l'art
Hiligsmann, Serge ULg; Beckers, Laurent ULg; Masset, Julien ULg et al

in Récents progrès en génie des procédés (2011, December 01)

Hydrogen is being considered as an ideal and clean energy carrier. The recent advances to produce biohydrogen from renewable sources such as biomass and particularly by fermentation of carbohydrate-rich ... [more ▼]

Hydrogen is being considered as an ideal and clean energy carrier. 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 enables both organic waste treatment and renewable energy production to be coupled. The paper presents the state of the art about the different hydrogen-producing microorganisms and the parameters that have been investigated in order to improve the hydrogen production yields and rates. [less ▲]

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See detailFermentative biohydrogen production in a novel biodisc bioreactor: Principle and Improvement
Beckers, Laurent ULg; Hiligsmann, Serge ULg; Masset, Julien ULg et al

in Bozhou, Li (Ed.) Low Carbon Earth Summit 2011 Proceeding (2011, October 23)

In order to produce hydrogen at high yields and production rates, the biotechnological process needs to be further optimized and efficient bioreactors must be designed. A biodisc bioreactor has been ... [more ▼]

In order to produce hydrogen at high yields and production rates, the biotechnological process needs to be further optimized and efficient bioreactors must be designed. A biodisc bioreactor has been design and investigated to produce biohydrogen from glucose by the Clostridium butyricum CWBI1009 strain at a high yield and production rate. This reactor, working continuously, has an internal volume of 2.3l but a working volume (liquid phase) of 300ml. Firstly, it enhances the hydrogen production rate (by about 3 times more than a completely stirred bioreactor) by partially fixing the bacteria on the porous support and thus increasing the cell concentration in the bioreactor (decoupling of HRT and SRT). Secondly, the rotating biodisc design enables efficient gas transfer (hydrogen and carbon dioxyde) from the liquid phase where it is produced by the bacteria to the headspace. Indeed, this is an important way to increase hydrogen production yields (by about 25% compared to a completely stirred bioreactor) by allowing the bacteria to focus on the metabolites pathways that produce more hydrogen. Other reactors designs have shown such good results by increasing the interfacial surface. [less ▲]

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See detailMICRO-H2 – Microbiological production of hydrogen: study of microalgal and bacterial processes
Calusinska, Magdalena ULg; Joris, Bernard ULg; Wilmotte, Annick ULg et al

Poster (2011, September 07)

The project MICRO-H2 aims to study and exploit the microbial (bacterial and algal) production of hydrogen (H2). In addition to building a competence centre around the H2 production by microorganisms and ... [more ▼]

The project MICRO-H2 aims to study and exploit the microbial (bacterial and algal) production of hydrogen (H2). In addition to building a competence centre around the H2 production by microorganisms and the molecular monitoring of the processes, this project tries to address two main socio-economic issues. First, transport and many economic activities will be based on hydrogen energy in the near future. Secondly, many researches and technology developments deal with renewable resources. Therefore, a new integrated technology for a sustainable development should be promoted. Photofermentation and dark-fermentation are the most promising ways to produce biohydrogen. The main advantage of the first process is the complete conversion of substrate, if any, to hydrogen. However, present H2-production rates by microalgae remain low. Therefore, a better understanding of the microalgal hydrogen metabolism and rate improvements by genetic engineering are needed. On the other hand, dark-fermentation achieves at present far higher H2-production rates, but improvements are expected through monitoring and optimisation of bacterial diversity and activity. The objectives about bacterial H2 production were to increase knowledge, stability potentialities and investigation skills about the consortia of bacteria involved in bioreactors treating wastewater rich in carbohydrates to produce biohydrogen. The project focused mainly on the study of the potentialities of different consortia, with a focus on Clostridium strains. Concerning the microalgal production of H2, the objectives were to increase knowledge on the metabolic interactions that determine H2 evolution at the cellular level and to produce new strains with increased ability for H2 production in the two-stage process. [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 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 detailClotridial hydrogenases and the biohydrogen production
Calusinska, Magdalena ULg; Hamilton, Christopher ULg; Masset, Julien ULg et al

Poster (2010, July 01)

Among the large variety of microorganisms capable of fermentative hydrogen production, strict anaerobes such as Clostridium spp. are one of the most widely studied. They produce hydrogen by butyric and ... [more ▼]

Among the large variety of microorganisms capable of fermentative hydrogen production, strict anaerobes such as Clostridium spp. are one of the most widely studied. They produce hydrogen by butyric and mixed-acid fermentations at optimal pH values ranging from 4.5 to 5.5. While fermentative conditions such as substrate type, pH, hydraulic and solid retention time, H2 partial pressure and the concentration of acids produced have been extensively studied and optimized, relatively little is known about the different forms of hydrogenases present in clostridia. Building on previous reports [1, 2] and by analyzing sequenced genomes, we found that [FeFe] hydrogenases are not a homogenous group of enzymes, but exist in multiple forms with different modular structures and are especially abundant in Clostridum spp. [3]. However, among the numerous studies performed on fermentative hydrogen production by Clostridium sp., only a few are specifically concerned with hydrogenases. Even there the authors focus on one type of [FeFe] hydrogenase, (CpI-like) without considering the existence of multiple forms of this enzyme within one species. Therefore, we focused our research on the better characterization of different forms of hydrogenases present in the genus Clostridium. Using newly designed degenerate primers, specific for clostridial hydrogenases, we amplified different hydrogenases from our species of interest. Further, by designing specific qPCR assays we have quantitatively targeted different hydrogenases. By analyzing differential gene expression, according to applied growth conditions, we believe to optimize the hydrogen production process in order to achieve better production rates. To conclude, we think that a a precise knowledge of hydrogen metabolism and hydrogenases is essential to optimization of the biohydrogen production process and should therefore be a goal for future research. [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 detailThe diversity of Clostridial hydrogenases and biohydrogen production
Calusinska, Magdalena ULg; Savichtcheva, Olga; Masset, Julien ULg et al

Poster (2009, June 18)

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean ... [more ▼]

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean, and transportable energy carrier. Some microorganisms can produce hydrogen during a reversible reduction of protons to dihydrogen, a reaction which is catalyzed by hydrogenases [1]. Hydrogenases belong to an iron – sulphur protein family, that contains active sites consisting of inorganic sulfide and iron atoms bound to the polypeptide chain. On the basis of their bimetallocenter composition hydrogenases are divided into three main groups, phylogenetically not related: [NiFe] hydrogenases, [Fe] only hydrogenases and ‘metal – free hydrogenases’ which were described in methanogenic Archaea only. [NiFe] hydrogenases, composed of at least two subunits are well characterized and widely distributed between Archaea and Bacteria but only a few representatives of Clostridium possess this type of enzyme. On the other hand, [Fe] only hydrogenases, being usually monomeric enzymes and restricted to Bacteria and a few eukaryotic species are far less described. These proteins, being omnipresent catalysts of many biological reactions, are especially abundant in Clostridia. The physiological function of Clostridial [Fe] only hydrogenases is to dispose under the form of hydrogen, of the excess of reducing power generated during the fermentation of carbohydrates. The unusual diversity of forms of [Fe] only hydrogenases within Clostridia seems to support the central role of this enzyme in cell metabolism and to facilitate the quick adaptation of the host to changing environmental conditions. Moreover, the presence of multiple putative operons encoding for multisubunit [Fe] only hydrogenases in the genomes of sequenced Clostridium spp. is highlighting the need to study the new, not yet described function of these ostensibly simple proteins. In this project, we have focused our effort on the molecular characterization of key enzymes involved in the process of biohydrogen production with a special interest in Clostridium species. By applying molecular techniques on samples from different kinds of bioreactors, we want to select highly productive species in terms of hydrogen generation. We also believe that gene expression profiling will provide new data on the possible function and activity of different hydrogenases involved in the process. The better understanding of hydrogen metabolism is essential for its sustainable production. [less ▲]

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