References of "Wilmotte, Annick"
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See detailThe MicroH2 project:an association of four laboratories to improve theknowledge on biohydrogen production precesses
Beckers, Laurent ULg; Calusinska, Magdalena ULg; Hamilton, Christopher ULg et al

Poster (2012, June 04)

This poster presents a collaborative research project (MicroH2) held at the University of Liège (Belgium) since 2007 (www.microh2.ulg.ac.be) and involving four different research groups. The project aims ... [more ▼]

This poster presents a collaborative research project (MicroH2) held at the University of Liège (Belgium) since 2007 (www.microh2.ulg.ac.be) and involving four different research groups. The project aims to develop a center of excellence in the fields of photo- and dark- biohydrogen production. Our studies contribute to improve the knowledge of the processes involved in the microbiological production of hydrogen, from a fundamental and practical point of view. Some results are highlighted here. The research concerning photofermentation focuses on the interactions between respiration, photosynthesis and H2-producing pathways in algal microorganisms, by using mitochondrial mutants and genetically modified strains with modified ability for hydrogen production [1-2]. To study the metabolism of the hydrogen production by anaerobic bacteria, pure cultures and defined consortia are used and their production of biogas and soluble metabolites is measured. Moreover, we have developed and optimized molecular tools, like quantitative RT-PCR and FISH, to monitor the variations of bacterial populations in novel bioreactors for hydrogen production [3-4]. We have also mined the complete genomes of Clostridium spp. for putative hydrogenase genes and found a large diversity of them [5]. [less ▲]

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See detailTHREE NEW BCCM PUBLIC COLLECTIONS ON DIATOMS, MYCOBACTERIA AND CYANOBACTERIA
Rigouts, Leen; Vanormelingen, Pieter; Vyverman, Wim et al

Poster (2012, June)

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See detailFermentative hydrogen production from glucose and starch using pure strains and artificial co-cultures ofClostridium spp.
Masset, Julien; Calusinska, Magdalena ULg; Hamilton, Christopher et al

in Biotechnology for biofuels (2012), 5(1), 35

ABSTRACT: BACKGROUND: Pure bacterial strains give better yields when producing H2 than mixed, natural communities. However the main drawback with the pure cultures is the need to perform the fermentations ... [more ▼]

ABSTRACT: BACKGROUND: Pure bacterial strains give better yields when producing H2 than mixed, natural communities. However the main drawback with the pure cultures is the need to perform the fermentations under sterile conditions. Therefore, H2 production using artificial co-cultures, composed of well characterized strains, is one of the directions currently undertaken in the field of biohydrogen research. RESULTS: Four pure Clostridium cultures, including C. butyricum CWBI1009, C. pasteurianum DSM525, C. beijerinckii DSM1820 and C. felsineum DSM749, and three different co-cultures composed of (1) C. pasteurianum and C. felsineum, (2) C. butyricum and C. felsineum, (3) C. butyricum and C. pasteurianum, were grown in 20 L batch bioreactors. In the first part of the study a strategy composed of three-culture sequences was developed to determine the optimal pH for H2 production (sequence 1); and the H2-producing potential of each pure strain and co-culture, during glucose (sequence 2) and starch (sequence 3) fermentations at the optimal pH. The best H2 yields were obtained for starch fermentations, and the highest yield of 2.91 mol H2/ mol hexose was reported for C. butyricum. By contrast, the biogas production rates were higher for glucose fermentations and the highest value of 1.5 L biogas/ h was observed for the co-culture (1). In general co-cultures produced H2 at higher rates than the pure Clostridium cultures, without negatively affecting the H2 yields. Interestingly, all the Clostridium strains and co-cultures were shown to utilize lactate (present in a starch-containing medium), and C. beijerinckii was able to re-consume formate producing additional H2. In the second part of the study the co-culture (3) was used to produce H2 during 13 days of glucose fermentation in a sequencing batch reactor (SBR). In addition, the species dynamics, as monitored by qPCR (quantitative real-time PCR), showed a stable coexistence of C. pasteurianum and C. butyricum during this fermentation. CONCLUSIONS: The four pure Clostridium strains and the artificial co-cultures tested in this study were shown to efficiently produce H2 using glucose and starch as carbon sources. The artificial co-cultures produced H2 at higher rates than the pure strains, while the H2 yields were only slightly affected. [less ▲]

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See detailCyanobacterial diversity for an anthropogenic impact assessment in the Sor Rondane Mountains area, Antarctica
Fernandez-Carazo, Rafael; Namsaraev, Zorigto; Mano, Marie-José ULg et al

in Antarctic Science (2012), 24(3), 229-242

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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 detailGenetic diversity and amplification of different clostridial [FeFe] hydrogenases by group-specific degenerate primers
Calusinska, Magdalena ULg; Joris, Bernard ULg; Wilmotte, Annick ULg

in Letters in Applied Microbiology (2011), 53

Aims: The aim of this study was to explore and characterize the genetic diversity of [FeFe] hydrogenases in a representative set of strains from Clostridium sp. and to reveal the existence of neither yet ... [more ▼]

Aims: The aim of this study was to explore and characterize the genetic diversity of [FeFe] hydrogenases in a representative set of strains from Clostridium sp. and to reveal the existence of neither yet detected nor characterized [FeFe] hydrogenases in hydrogen-producing strains. Methods and Results: The genomes of 57 Clostridium strains (34 different genotypic species), representing six phylogenetic clusters based on their 16S rRNA sequence analysis (cluster I, III, XIa, XIb, XIV and XVIII), were screened for different [FeFe] hydrogenases. Based on the obtained alignments, ten pairs of [FeFe] hydrogenase cluster-specific degenerate primers were newly designed. Ten Clostridium strains were screened by PCRs to assess the specificity of the primers designed and to examine the genetic diversity of [FeFe] hydrogenases. Using this approach, a diversity of hydrogenase genes was discovered in several species previously shown to produce hydrogen in bioreactors: Clostridium sartagoforme, Clostridium felsineum, Clostridium roseum and Clostridium pasteurianum. Conclusions: The newly designed [FeFe] hydrogenase cluster-specific primers, targeting the cluster-conserved regions, allow for a direct amplification of a specific hydrogenase gene from the species of interest. Significance and Impact of the Study: Using this strategy for a screening of different Clostridium ssp. will provide new insights into the diversity of hydrogenase genes and should be a first step to study a complex hydrogen metabolism of this genus. [less ▲]

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See detailOrgano-mineral imprints in fossil cyanobacterial mats of an Antarctic lake
Lepot, Kevin ULg; Deremiens; Namsaraev, Zorigto ULg et al

Poster (2011, April 07)

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See detailNovel FISH and quantitative PCR protocols to monitor artificial consortia composed of different hydrogen-producing Clostridium spp.
Savichtcheva, Olga; Joris, Bernard ULg; Wilmotte, Annick ULg et al

in International Journal of Hydrogen Energy (2011), 36

The use of an artificial consortium composed of selected hydrogen-producing species, instead of a natural anaerobic sludge, has been proposed for biohydrogen production. In order to monitor such a ... [more ▼]

The use of an artificial consortium composed of selected hydrogen-producing species, instead of a natural anaerobic sludge, has been proposed for biohydrogen production. In order to monitor such a consortium composed of different Clostridium spp., new protocols were tested for two different assays, FISH and qPCR. New species-specific FISH probes and qPCR primer sets were developed and optimised for three strains: Clostridium butyricum, Clostridium felsineum and Clostridium pasteurianum, that were used in a consortium. Application of a fast two-step FISH protocol, with pre-treatment step at 90 C for 5 min and a subsequent hybridisation step at higher temperature (55 C) for 20 min resulted in a much shorter analytical time compared to the standard FISH procedure (46 C for 2e3 h) and gave a high hybridisation performance. Moreover, to accurately quantify each microorganism by qPCR assay, two innovations were tested: the direct use of cell lysates (omitting the DNA extraction step) and the use of two alternative molecular markers, recA and gyrA. These markers are present in single copies in the genome, whereas there are multiple copies of the ribosomal operons. This resulted in the development of accurate, reliable and fast FISH and qPCR assays for routine monitoring of the dynamics of artificial hydrogen-producing microbial consortia. Moreover, both techniques can be easily adapted to new Clostridium strains. [less ▲]

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See detailA collection of polar cyanobacteria to contribute to the inventory of the biodiversity and discover the biotechnological potential
Wilmotte, Annick ULg; Waleron, Kzryzstof; Waleron, Malgorzata et al

Poster (2011, February)

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See detailAntarctic cyanobacterial diversity: how important are the geographical and ecological factors?
De Carvalho Maalouf, Pedro ULg; Lambion, Alexandre ULg; Gillard, Benjamin et al

Conference (2011, February)

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See detailCYANOBACTERIAL BLOOMS : TOXICITY, DIVERSITY, MODELLING AND MANAGEMENT
Descy, Jean-Pierre; Pirlot, S; Verniers, G et al

Report (2011)

The B-BLOOMS2 project aimed to deepen knowledge of cyanobacterial blooms in Belgium, improve the modelling for prediction and early-warning, develop operational monitoring structures and tools, and ... [more ▼]

The B-BLOOMS2 project aimed to deepen knowledge of cyanobacterial blooms in Belgium, improve the modelling for prediction and early-warning, develop operational monitoring structures and tools, and propose strategies to reduce the impact of cyanobacterial blooms. From a scientific point of view, the research programme focused on: - Collection of physical, chemical, biological and meteorological data on selected reference waterbodies plagued by toxic cyanobacterial blooms in Flanders, Brussels and Wallonia; - Identification and study of the toxigenic cyanobacteria present in the Belgian samples using molecular tools on samples and strains, including genetic diversity and factors regulating their population dynamics; - Measurement of the major cyanotoxins present in the blooms and water samples by analytical methods; - Development and test of management scenarios for control or mitigation of cyanobacterial blooms in one reservoir using integrated watershed models; - Development of a statistical predictive model for a series of urban ponds. From a practical and science policy point of view, B-BLOOMS2 aimed to: - Implement a network of samplers based on existing monitoring programmes of surface waters or on collaboration with health authorities or environmental organisations (BLOOMNET); - Transfer knowledge about methods of monitoring and analysis of blooms to the water/health authorities and environmental organisations by hands-on courses in our laboratories and field sites; - Reinforce the communication to and with authorities and the general population, to raise public awareness, contribute to future guidelines and risk assessment procedures, and improve monitoring and management. [less ▲]

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See detailLow cyanobacterial diversity in biotopes of the Transantarctic Mountains and Shackleton Range (80-82°S), Antarctica.
Fernandez, Rafael; Hodgson, Dominic; Convey, Pete et al

in FEMS Microbiology Ecology (2011), 77

The evolutionary history and geographical isolation of the Antarctic continent have produced a unique environment rich in endemic organisms. In many regions of Antarctica, cyanobacteria are the dominant ... [more ▼]

The evolutionary history and geographical isolation of the Antarctic continent have produced a unique environment rich in endemic organisms. In many regions of Antarctica, cyanobacteria are the dominant phototrophs in both aquatic and terrestrial ecosystems. We have used microscopic and molecular approaches to examine the cyanobacterial diversity of biotopes at two inland continental Antarctic sites (80-82°S). These are amongst the most southerly locations where freshwater-related ecosystems are present. Results showed a low cyanobacterial diversity, with only 3-7 Operational Taxonomic Units (OTUs) per sample obtained by a combination of strain isolations, clone libraries and DGGE based on 16S rRNA genes. One OTU was potentially endemic to Antarctica and is present in several regions of the continent. Four OTUs were shared by the samples from Forlidas Pond and the surrounding terrestrial mats. Only one OTU, but no Internal Transcribed Spacer (ITS) sequences, was common to Forlidas Pond and Lundström Lake. The ITS sequences were shown to further discriminate different genotypes within the OTUs. ITS sequences from Antarctic locations appear more closely related to each other than to non-Antarctic sequences. Future research in inland continental Antarctica will shed more light on the geographical distribution and evolutionary isolation of cyanobacteria in these extreme habitats. [less ▲]

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See detailPlectolyngbya hodgsonii: a novel filamentous cyanobacterium from Antarctic lakes
Taton, Arnaud; Wilmotte, Annick ULg; Smarda, Jan et al

in Polar Biology (2011), 34

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach ... [more ▼]

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach. This morphotype has several characters corresponding to the traditional genera Leptolyngbya (morphology of trichomes), Pseudophormidium (type of false branching) or Schizothrix (occasional multiple arrangement of trichomes in the sheaths). However, this cluster of strains is distinctly isolated according to its phylogenetic position (based on 16S rRNA gene sequences), and thus, a separate generic classification is justified. The cytomorphology of this generic entity is also characteristic. Therefore, a new genus (Plectolyngbya with the type species P. hodgsonii) was described. [less ▲]

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See detailOrgano-mineral imprints in fossil cyanobacterial mats of an Antarctic lake
Javaux, Emmanuelle ULg; Lepot, Kevin ULg; Deremiens, Leo et al

Poster (2010, December)

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See detailPotentiel secondary metabolite biosynthesis operons in environmental colonies of Woronischinia
Lara, Yannick ULg; Lambion, Alexandre ULg; Codd, Goeffrey A. et al

Poster (2010, September 01)

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See detailThe limnology and biology of the Dufek Massif, Transantarctic Mountains 82° South
Hodgson, Dominic A; Convey, Pete; Verleyen, Elie et al

in Polar Science (2010), 4

Very little is known about the higher latitude inland biology of continental Antarctica. In this paper we describe the limnology and biology of the Dufek Massif, using a range of observational ... [more ▼]

Very little is known about the higher latitude inland biology of continental Antarctica. In this paper we describe the limnology and biology of the Dufek Massif, using a range of observational, microscopic and molecular methods. Here two dry valleys are home to some of the southernmost biota on Earth. Cyanobacteria were the dominant life forms, being found in lakes and ponds, in hypersaline brines, summer melt water, relict pond beds and in exposed terrestrial habitats. Their species diversity was the lowest yet observed in Antarctic lakes. Green algae, cercozoa and bacteria were present, but diatoms were absent except for a single valve; likely windblown. Mosses were absent and only one lichen specimen was found. The Metazoa included three microbivorous tardigrades (Acutuncus antarcticus, Diphascon sanae and Echiniscus (cf) pseudowendti) and bdelloid rotifer species, but no arthropods or nematodes. These simple faunal and floral communities are missing most of the elements normally present at lower latitudes in the Antarctic which is probably a result of the very harsh environmental conditions in the area. [less ▲]

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See detailEvidence for widespread endemism among Antarctic micro-organisms
Vyverman, Wim; Verleyen, Elie; Wilmotte, Annick ULg et al

in Polar Science (2010), 4

Understanding the enormous diversity of microbes, their multiple roles in the functioning of ecosystems, and their response to large-scale environmental and climatic changes, are at the forefront of the ... [more ▼]

Understanding the enormous diversity of microbes, their multiple roles in the functioning of ecosystems, and their response to large-scale environmental and climatic changes, are at the forefront of the international research agenda. In Antarctica, where terrestrial and lacustrine environments are predominantly microbial realms, an active and growing community of microbial ecologists is probing this diversity and its role in ecosystem processes. In a broader context, this work has the potential to make a significant contribution to the long-standing debate as to whether microbes are fundamentally different from macroorganisms in their biogeography. According to the ubiquity hypothesis, microbial community composition is not constrained by dispersal limitation and is solely the result of species sorting along environmental gradients. However, recent work on several groups of microalgae is challenging this view. Global analyses using morphology-based diatom inventories have demonstrated that, in addition to environmental harshness, geographical isolation underlies the strong latitudinal gradients in local and regional diversity in the Southern hemisphere. Increasing evidence points to a strong regionalization of diatom floras in the Antarctic and sub- Antarctic regions, mirroring the biogeographical regions that have been recognized for macroorganisms. Likewise, the application of molecular-phylogenetic techniques to cultured and uncultured diversity revealed a high number of Antarctic endemics among cyanobacteria and green algae. Calibration of these phylogenies suggests that several clades have an ancient evolutionary history within the Antarctic continent, possibly dating back to 330 Ma. These findings are in line with the current view on the origin of Antarctic terrestrial metazoa, including springtails, chironomids and mites, with most evidence suggesting a long history of geographic isolation on a multi-million year, even pre-Gondwana break-up timescale [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 detailB-BLOOMS 2: Importance and diversity of cyanobacterial blooms in Belgium
Wilmotte, Annick ULg

Scientific conference (2010, June 06)

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