Dans la nature, les microorganismes s’organisent en communauté où la concertation de leur métabolisme leur permet de coloniser des endroits peu propices. La biodégradation de la matière organique nécessite un couplage métabolique entre les différents microorganismes impliqués et constitue un modèle de choix pour l'étude des interactions où leurs relations restent mal définies et nécessitent d’être mieux caractérisées. Le décryptage du mécanisme mis en jeu permettrait d'optimiser la production de composés bioénergétiques comme l'hydrogène. Nous avons étudié un consortium composé de Desulfovibris vulgaris Hildenborough, une bactérie sulfato-réductrice et de Clostridium acetobutylicum, une bactérie fermentaire. Ces deux bactéries sont retrouvées dans des consortia naturels impliqués dans la dégradation de la biomasse. Des approches de microbiologie, de métabolisme et de microscopie ont permis de démontrer l’existence d’une interaction physique et d'un échange de molécules cytoplasmiques entre les deux bactéries. Ceci s'associe à une réorientation du flux de carbone dans la bactérie C. acetobutylicum qui se traduit par une production d’hydrogène accrue. Ce comportement est lié aux conditions de stress nutritionnel pour la bactérie D. vulgaris. De plus, des molécules signal de type AI-2 jouent un rôle important dans la mise place de l'interaction physique. Un inhibiteur de cette interaction, produit par D. vulgaris dans certaines conditions, a été découvert. Ce travail a permis d'acquérir de nouvelles connaissances sur les relations métaboliques et les interactions physiques entre les bactéries impliquées dans la biodégradation de la biomasse dans un consortium. / In nature microorganisms live in communities, in which the complementarity of their metabolism allows them to colonize less favourable ecological niches. Biodegradation of organic matter requires tight metabolic coupling between the different microorganisms involved, and constitutes an ideal model for studying the interactions between them, which are still not well established and require further characterization. Furthermore, deciphering the metabolic couplings established between the partners would allow optimization of this process for production of compounds of biotechnological interest, such as hydrogen. During the course of this work we have studied an artificial consortium constituted by Desulfovibris vulgaris Hildenborough sulphate-reducing bacterium, and Clostridium acetobutylicum a fermentative bacterium; both of them are found in natural consortia involved in biomass degradation. Microbiological, metabolic and microscopic approaches allowed us to show the existence of a physical interaction, with exchange of cytoplasmic molecules, between the two bacteria. This is associated with reorientation of the carbon flux in Clostridium acetobutylicum, resulting in increased hydrogen production. This behaviour is linked with the nutritional stress of D. vulgaris. Moreover, AI-2 type signal molecules produced in these conditions are crucial for the physical interaction between the two bacterial partners. An inhibitor produced by D. vulgaris in certain conditions has been discovered. This work has allowed us to acquire new knowledge about metabolic relations and physical interactions between bacteria involved in biomass degradation in a consortium

Este estudo analisa a indústria de consórcio a partir da prestação desse serviço pelos bancos de varejo, buscando compreender as transformações mais relevantes que ocorreram a partir de então. Para tanto, analisa-se o produto consórcio: sua origem e evolução, seu funcionamento, sua particularidade como forma de aquisição de bens, seu atrativo. É feita também a comparação do consórcio com outras formas de aquisição. Como forma de justificar o interesse dos bancos de varejo em administrar e constituir grupos de consórcio fez-se uma revisão na história recente do Sistema Financeiro Nacional com destaque para a importância das receitas de prestação de serviços numa economia com preços estabilizados. Para a análise da indústria de consórcio buscou-se, com base na participação do mercado, em seus vários segmentos autorizados, explicação para as modificações e o comportamento do setor, a partir do ingresso dos bancos de varejo. / This study analyzes the industry of consortium since banks started retailing it. It tries to understand the most relevant transformations that have taken place since that day. In order to do so, the following aspects of the product consortium are analyzed: its origin and evolution, the way it works, its peculiarities as a way to acquire goods and its attractiveness. The consortium is also compared to other modes of good acquisition. In an attempt to justify the interest of retail banks in managing and assembling consortia, the recent history of the National Financial System of Brazil is reviewed. This review highlights the importance of the income which is a result of services offered in a stabilized price-economy. The changes in behavior and the modifications in the consortium industry caused by the joining of the retail banks in this business are analyzed on the base of the participation of these institutions in this particular industry.

Este estudo analisa a indústria de consórcio a partir da prestação desse serviço pelos bancos de varejo, buscando compreender as transformações mais relevantes que ocorreram a partir de então. Para tanto, analisa-se o produto consórcio: sua origem e evolução, seu funcionamento, sua particularidade como forma de aquisição de bens, seu atrativo. É feita também a comparação do consórcio com outras formas de aquisição. Como forma de justificar o interesse dos bancos de varejo em administrar e constituir grupos de consórcio fez-se uma revisão na história recente do Sistema Financeiro Nacional com destaque para a importância das receitas de prestação de serviços numa economia com preços estabilizados. Para a análise da indústria de consórcio buscou-se, com base na participação do mercado, em seus vários segmentos autorizados, explicação para as modificações e o comportamento do setor, a partir do ingresso dos bancos de varejo. / This study analyzes the industry of consortium since banks started retailing it. It tries to understand the most relevant transformations that have taken place since that day. In order to do so, the following aspects of the product consortium are analyzed: its origin and evolution, the way it works, its peculiarities as a way to acquire goods and its attractiveness. The consortium is also compared to other modes of good acquisition. In an attempt to justify the interest of retail banks in managing and assembling consortia, the recent history of the National Financial System of Brazil is reviewed. This review highlights the importance of the income which is a result of services offered in a stabilized price-economy. The changes in behavior and the modifications in the consortium industry caused by the joining of the retail banks in this business are analyzed on the base of the participation of these institutions in this particular industry.

Este estudo analisa a indústria de consórcio a partir da prestação desse serviço pelos bancos de varejo, buscando compreender as transformações mais relevantes que ocorreram a partir de então. Para tanto, analisa-se o produto consórcio: sua origem e evolução, seu funcionamento, sua particularidade como forma de aquisição de bens, seu atrativo. É feita também a comparação do consórcio com outras formas de aquisição. Como forma de justificar o interesse dos bancos de varejo em administrar e constituir grupos de consórcio fez-se uma revisão na história recente do Sistema Financeiro Nacional com destaque para a importância das receitas de prestação de serviços numa economia com preços estabilizados. Para a análise da indústria de consórcio buscou-se, com base na participação do mercado, em seus vários segmentos autorizados, explicação para as modificações e o comportamento do setor, a partir do ingresso dos bancos de varejo. / This study analyzes the industry of consortium since banks started retailing it. It tries to understand the most relevant transformations that have taken place since that day. In order to do so, the following aspects of the product consortium are analyzed: its origin and evolution, the way it works, its peculiarities as a way to acquire goods and its attractiveness. The consortium is also compared to other modes of good acquisition. In an attempt to justify the interest of retail banks in managing and assembling consortia, the recent history of the National Financial System of Brazil is reviewed. This review highlights the importance of the income which is a result of services offered in a stabilized price-economy. The changes in behavior and the modifications in the consortium industry caused by the joining of the retail banks in this business are analyzed on the base of the participation of these institutions in this particular industry.

No description available.

Thesis (Preliminary M.A.) from the Department of Politics, University of Adelaide.

No description available.

This feasibility study was performed at Virginia Polytechnic Institute and State University (Blacksburg, VA) in collaboration with BioSystems Technology, Inc. (Blacksburg, VA). In this study, degradability of PCBs (Aroclor 1242) from an aged surface soil was evaluated using serum bottle microcosms containing aceticlastic methanogenic consortium, enriched from a municipal anaerobic digester. Two different experiments, "intermediate feed" and "starve and feed" were conducted by manipulating the methanogenic consortium with different amounts of acetate feeding, during 30 days of incubation. Disappearance of Aroclor 1242 in the microcosms was quantified using gas chromatography (GC). Significant differences in Aroclor 1242 removal between inoculated and uninoculated (control) microcosms were observed suggesting that the methanogenic consortium was responsible for Aroclor 1242 disappearance. However, GC-mass spectrometry (GC-MS) results could not confirm that disappearance of Aroclor 1242 was due to anaerobic dehalogenation. From another experiment, it was confirmed that removal of Aroclor 1242 was not due to evaporation losses during sample extraction. Toxicity of an aged Aroclor 1242 contaminated surface soil was evaluated on an aceticlastic methanogenic consortium, enriched from a municipal anaerobic digester. Microcosms were set up using different amounts of soil and inoculum. Total gas production in the microcosms was monitored during 30 days of incubation, using a glass syringe. Total methane production in the microcosms was quantitated using GC. Toxicity of the soil on the methanogenic inoculum was determined based on the decreased rate of methane production in the microcosms relative to non- soil containing controls. Compared to the control, there was reduction in total methane production in soil containing microcosms. Between 3-27% reduction in total methane production was noticed in microcosms containing different amounts of soil and consortium. Reduction in methane production seemed to increase with increasing amount of soil. Whether this decrease in methane production was due to toxicity of Aroclor 1242 on the methanogenic consortium or due possibly to the toxicity of trapped oxygen in the soil could not be determined. The rate of gas production in the soil microcosm was linear. / Master of Science

Les effluents de distillerie de mélasse de canne à sucre génèrent une pollution environnementale due à, d’une part de grands volumes et d’autres part à la présence de composés de couleur brune foncée, connus sous le nom de mélanoïdines. Dans cette étude, un consortium bactérien CONS8 isolé dans des sédiments de chute d'eau a été choisi comme consortium apte à la décoloration de la mélasse. On a montré que le consortium CONS8 pouvait décolorer, trois eaux usées synthétiques différentes, élaborées respectivement à base de Viandox (13,48% v/v), d’eau usée de mélasse de betterave (41,5% v/v) ou d’eau usée de mélasse de canne à sucre (20% v/v). Les décolorations obtenues en 2 jours seulement, en fioles d’Erlenmeyer sont respectivement de 9,5, à 8,02 et à 17,5%. Quatre bactéries prédominantes ont été identifiées dans le consortium CONS8 par l'analyse de l'rADN 16S. Sur la base de cette identification, et afin de réaliser la décoloration la plus élevée, un consortium bactérien artificiel MMP1 a été reconstruit avec Klebsiella oxytoca, Serratia mercescens (T2) et la bactérie inconnue DQ817737 (T4). Dans des conditions optimisées (aération, pH) le consortium bactérien MMP1 a permis de décolorer l'eau usée synthétique contenant de la mélanoidine à 18,3% en 2 jours. La comparaison de la décoloration par le consortium MMP1 avec un milieu abiotique a démontré que la décoloration était principalement due à l'activité biotique des cellules bactériennes, sans aucun phénomène d'adsorption. Un complément en minéraux et vitamines B n'a pas amélioré la décoloration de mélanoïdines avec le consortium bactérien MMP1. Enfin, les performances d'un bioréacteur à membrane pour traiter les eaux résiduaires synthétiques contenant de la mélanoïdine ont été évaluées à l’échelle du laboratoire. L'ensemencement du réacteur a été réalisé avec un inoculum sur la base du consortium MMP1. Le réacteur a fonctionné sous plusieurs conditions de temps de séjour hydrauliques (HRT) de 15, 20, et 40 heures. Les performances ont été analysées en termes de DCO (demande chimique en oxygène), décoloration et croissance de biomasse. Les résultats ont indiqué qu’une efficacité accrue d’élimination de la DCO et de la couleur ont été obtenues avec le HRT le plus long. / Distillery effluent from sugarcane molasses leads to an environmental pollution due to its large volume and the presence of dark brown colored compounds, known as melanoidins. In this study, a bacterial consortium CONS8 isolated from waterfall sediments in Maehongsorn province was selected as a molasses-decolorizing consortium. Consortium CONS8 was able to decolorize, only within 2 days, in Erlenmeyer flasks, three different synthetic wastewaters containing either Viandox sauce (13.5% v/v), beet molasses wastewater (41.5% v/v) or sugarcane molasses wastewater (20% v/v) at 9.5, 8.0 and 17.5%, respectively. Four predominant bacteria present in the consortium CONS8 were identified by the 16S rDNA analysis. To achieve the highest decolorization, the artificial bacterial consortium MMP1 comprising Klebsiella oxytoca, Serratia mercescens (T2) and unknown bacterium DQ817737 (T4), was constructed. Under optimized conditions (aeration, pH), the bacterial consortium MMP1 was able to decolorize the synthetic melanoidins-containing wastewater at 18.3% within 2 days. The comparison of decolorization by the consortium MMP1 with abiotic control proved that the color removal for synthetic melanoidins-containing wastewater medium was mainly due to biotic activity of bacterial cells, without any adsorption phenomena. Supplement of nutrients and vitamin B did not promote melanoidins decolorization by bacterial consortium MMP1. Finally, the performance of a membrane bioreactor (MBR) for synthetic melanoidins-containing wastewater treatment was investigated at laboratory scale, with a mineral membrane. The reactor seeding was made with the MMP1 bacterial consortium inoculum. The reactor was performed with several hydraulic retention times (HRT) of 15, 20, and 40 hours. The performances were analyzed in terms of COD, color removal and biomass in the reactor. The results indicated that the higher COD and color removal efficiency were achieved with the longer HRT.

The degradation of toxic and volatile contaminants in aqueous streams is considered a challenge using conventional bioremediation strategies. At moderate concentrations, toxic contaminants induce microbial inhibition, which results in an overall decrease of reaction rates. On the other hand, volatile compounds are often stripped out of solution into the atmosphere during aeration in conventional wastewater treatments, and are not treated. The addition of a second non-aqueous phase with affinities for the contaminants can reduce aqueous concentrations to sub-inhibitory levels and also decrease contaminant volatilization, while still allowing controlled release of contaminants back to the microbial population; such systems have been denoted as Two Phase Partitioning Bioreactor (TPPB). The current work examined and compared the performance of solid-liquid TPPB to a liquid-liquid TPPB and a single phase system. The systems were compared in the simultaneous degradation of phenol and butyl acetate, two substrates known for their relatively high levels of toxicity and volatility, respectively. The solid-liquid TPPB, using 2 polymers selected heuristically, showed an improvement of 40 and 54 % in phenol degradation rates compared to the single phase and the liquid-liquid systems. Additionally, the solid-liquid system presented a 55 and 11 % enhancement in the amount of butyl acetate degraded. At higher initial substrate concentration the solid-liquid TPPB showed an improvement in the phenol degradation rate and the amount of butyl acetate degraded of 44 and 94 % respectively, compared to the single phase system. In order to rationalize polymer screening for solid-liquid TPPBs, selection criteria based on first principles were developed, and were based on consideration of polymer accessibility and polymer-solute thermodynamic affinity. Polymer accessibility was evaluated by considering glass transition temperature (Tg) and degree of crystallinity, while polymer-solute thermodynamic affinity was assessed using three different methods, Hildebrand solubility parameters, Hansen iii Solubility Parameters (HSP) and activity coefficients at infinite dilution. It was found that the HSP method gave the best trends and its predictions had better agreement with the experimental results. Consequent biodegradation experiments with a single, rationally selected polymer, and a mixture of waste polymers, demonstrated the superior performance of rational selected polymers. / Thesis (Master, Chemical Engineering) -- Queen's University, 2013-05-02 16:24:39.655