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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Aplicação de fosfolipase A2 de veneno de serpentes em biocatalise / Application of phospholipase A2 of serpents' poisons in biocatalysis

Pirolla, Renan Augusto Siqueira 13 August 2018 (has links)
Orientador: Jose Augusto Rosario Rodrigues / Dissertação ( mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-13T18:43:14Z (GMT). No. of bitstreams: 1 Pirolla_RenanAugustoSiqueira_M.pdf: 4621563 bytes, checksum: 4794daa19c9ceefe37205a1eed1b647b (MD5) Previous issue date: 2009 / Resumo: O projeto explora o potencial catalítico de fosfolipases A2, isoladas de venenos de serpentes brasileiras para efetuar resolução enzimática de substratos com relevância científica, visto que nenhum trabalho anterior foi feito analisando-se sua enantiosseletividade. Foram feitos estudos sobre a resolução do Binol, do a-tetralol, do 1-feniletanol, do para-nitro-1-feniletanol, do ácido 3-(2-bromo-hexanoiloxi)-4-nitrobenzóico e ácido 3-(2-metil-hexanoiloxi)-4-nitrobenzóico.Devido a dificuldade de obtenção e purificação das fosfolipases, a enzima foi imobilizada utilizando a formação de um agregado com ligações cruzadas (Cross-Linked Enzyme Aggregate . CLEA). Os agregados foram produzidos com quatro tipos de precipitantes (solução 55 % de sulfato de amônio, polietilenoglicol 600 Da, dimetoxietano e acetona) e dois adicionantes (TRITON-X100 e polietilenodiimina). Com os testes, observou-se que o CLEA formado com sulfato de amônio, sem adicionante apresentou os melhores resultados, sendo utilizado nas reações de biocatálise. A resolução dos substratos foi feita com a esterificação dos álcoois, formando-se ésteres (acetatos, propanoatos e hexanoatos), e posterior hidrólise com a enzima não-imobilizada e CLEA da fosfolipase A2, para comparação. Alíquotas das reações foram e analisadas por GC/FID com fase estacionária quiral para estudo dos excessos enantioméricos. As reações foram feitas a temperatura ambiente e a 45 °C. Os resultados indicam atividade enzimática sendo possível obter o tetralol com 16% de e.e. utilizando-se o CLEA e o p-nitro-1-feniletanol com 19% de ee usando-se a PLA2 livre. Os outros álcoois foram obtidos com baixos ee. O ácido 3-(2-bromo-hexanoiloxi)-4-nitrobenzóico não pode ser analisado por sofrer hidrólise química completa no meio reacional, e com a hidrólise do ácido 3-(2-metil-hexanoiloxi)-4-nitrobenzóico foi possível a obtenção do ácido 2-metil-hexanóico com 9 % utilizando-se CLEA e 7 % com a enzima livre. A baixa enantiosseletividade foi interpretada como decorrente da fraca interação dos substratos com o sítio ativo da enzima / Abstract: This project explores the catalytic potential of fosfolipases A2, isolated from poisons of brazilian serpents to effect enzymatic substrate resolution with scientific relevance, since no previous work was made analyzing its enantioselectivity. Studies on the resolution of several compounds had been made, including Binol, a-tetralol, 1-phenylethanol, para-nitro-1- phenylethanol, 3-(2-bromohexanoiloxy)-4-nitrobenzoic acid and 3-(2-methylhexanoiloxy)-4-nitrobenzoic acid.Due to difficulty of attainment and purification of the phospholipase, the enzyme was immobilized using the formation of an aggregate with cross-links (Cross-Linked Enzyme Aggregate ¿ CLEA). These aggregates had been produced with four types of precipitation agents (ammonium sulphate solution 55%, polietileneglycol 600 Da, dimethoxyethane and acetone) and two additives (TRITON-X100 and poliethylenediimine). With the tests, it was observed that the CLEA formed with ammonium sulphate, without additives presented the best results, being used in the reactions of biocatalysis.The resolution of substrates was made with the alcohol¿s esterification, forming different (acetates, propanoates and hexanoates) followed by hydrolysis with the free enzyme and CLEA, for comparison. Aliquots of the reactions had been made and analyzed with GC/FID with quiral stationary phase for study of the enantiomerics excesses. The reactions had been made at ambient temperature and 45 °C.The results indicate enzymatic activity and was possible to get tetralol with 16% of ee using CLEA and p-nitro-1-phenylethanol with 19% of ee. The other alcohols had been gotten with low ee. The 3- (2-bromohexanoiloxy) - 4-nitrobenzoic acid cannot be analyzed by suffering complete chemical hydrolysis during the reaction, and with hydrolysis of acid the 3- (2-metilhexanoiloxi) - 4-nitrobenzoic the attainment of the acid 2-metilhexanoic with 9% was possible using CLEA and 7% with the free enzyme. The low enantioselectivity was explained due to the weak interaction of substrates with the active site of enzyme / Mestrado / Quimica Organica / Mestre em Química
2

Imobilizácia lignolytických enzýmov

Schlosserová, Nikola January 2019 (has links)
Ligninolytic systems found their application in the food industry, but they are also used for the degradation of several xenobiotic compounds and dyes. This characteristic is making them be a useful tools for bioremediation purposes, that is why the interest in ligninolytic enzymes is increasing. The main aim of practical part was preparation of immobilized enzyme lignin peroxidase by method CLEA from fungus Piptoporus betulinus, Trametes gibbosa and their cocultivation. Activities of free and immobilized enzymes from these fungus were compared and measured by UV/VIS spectrometer. Conditions of precipitation and immobilization were specified by method CLEA. pH optimum for proteins precipitation were for Piptoporus betulinus pH 7,0, for Trametes gibbosa pH 5,0 and for cocultivation pH 6,0. The best concentration of glutaraldehyd, as a crosslinking agent, was for Piptoporus betulinus and cocultivation 50mM and for Trametes gibbosa 10mM. By immobilization, the activity of all enzymes were successfully increased up by 20 %. After optimalization of CLEA enzymes preparation, other parameters such as pH optimum, stability and temperature optimum and stability were tested. All enzymes had their pH optimum in acidic to slightly acidic environment and temperature optimum was in range from 30 °C to 40 °C. Immobilized CLEA enzyme from cocultivation was the most stable for all the enzymes. Free and CLEA enzymes were tested on synthetic food dyes, while their biodegradable ability was examined. Decrease of dyes was measured on HPLC with DAD detector. The sorption of fungi play an important role in this experiment, because fungi created mycelium and partially sorbed the dye. From this point of view, higher decolorization of dye in free enzymes in comparison with CLEA was observed. The best ability of decolorization was shown by a free enzyme from a Trametes gibossa, which after 14days of cultivation decolored more than 90 % dye. In total, significant decolorization (more than 80 % during 14 days) was achieved for azorubin. Degradation of dyes by CLEA was not so effective, which could be possibly caused by cultivation of enzymes without their substrate (veratrylalcohol). Cocultivation technique is very promising method how to increase LiP activity and concurrently create enzyme with improved properties.
3

Synthèse de biocatalyseurs versatiles pour l'élimination de polluants émergents des eaux usées

Touahar, Imad Eddine January 2014 (has links)
L’émergence de nouveaux contaminants dans les eaux usées requiert le développement de nouvelles techniques. En effet, les traitements classiques des stations d’épuration des eaux usées laissent entrer dans les matrices environnementales de nombreux contaminants organiques de faibles concentrations tels que les produits pharmaceutiques. Nous avons donc étudié l’élimination d’une variété de pharmaceutiques, représentatifs de leur classe, ou bien présentant une forte occurrence, ou encore des composés récalcitrants. Parmi ces pharmaceutiques on retrouve des anti-inflammatoires non stéroïdiens (acétaminophène, naproxène, acide méfénamique, kétoprofène, indométacine, diclofénac), un stimulant (caféine) deux antibiotiques (ciprofloxacine et triméthoprime), un anticonvulsif et régulateur de l’humeur (carbamazépine), un anxiolytique (diazépam) et deux fibrates (fénofibrate et bézafibrate). Parmi les techniques novatrices permettant de réaliser ce type d’élimination on retrouve certaines enzymes oxydatives qui sont capables de transformer de nombreux contaminants organiques que l’on retrouve dans les eaux usées. L’utilisation de trois enzymes de ce type, la laccase, la versatile peroxydase et la glucose oxydase, dans différentes combinaisons, a permis d’obtenir une élimination satisfaisante de la plupart des pharmaceutiques auxquels nous nous sommes intéressés, avec une efficacité optimale pour la combinaison des trois enzymes. Partant de ce constat, une combinaison plus stable de ces trois enzymes a été produite par une technique de co-aggrégation permettant de les insolubiliser tout en les regroupant par réticulation. Ceci facilite la réutilisation de ces biocatalyseurs, et augmente leur stabilité, ce qu’une caractérisation du biocatalyseur a permis de vérifier. Le biocatalyseur a alors pu être testé pour le traitement d’un cocktail des produits pharmaceutiques précédemment énoncés et a permis de réaliser une élimination de plus de 60 % de la plupart des composés dans des conditions qui ont été optimisées. Testé dans des eaux résiduaires urbaines prélevées à l’affluent de la station d’épuration de Magog (Québec), le biocatalyseur a permis une élimination de l’ordre de 25 % pour des concentrations très faibles (ppb) en acétaminophène.
4

Preparation Of Cross-linked Tyrosinase Aggregates

Aytar, Burcu Selin 01 June 2006 (has links) (PDF)
ABSTRACT PREPARATION OF CROSS-LINKED TYROSINASE AGGREGATES Aytar, Burcu Selin M.S., Department of Chemical Engineering Supervisor: Prof. Dr. Ufuk Bakir June 2006, 82 pages The aim of this study was to prepare cross-linked enzyme aggregate (CLEA) from crude mushroom (Agaricus bisporus) extract. However, the optimization of CLEA production was performed by using pure tyrosinase. Important parameters were determined as protein, ammonium sulfate and glutaraldehyde concentrations, CLEA particle size, and cross-linking temperature and period. On the other hand, the order of ammonium sulfate and glutaraldehyde addition did not affect the yield of CLEA. Optimum CLEA preparation conditions were 60 % ammonium sulfate saturation, 2 % (v/v) glutaraldehyde, and 3 hour cross-linking reaction at room temperature. Particle size of the CLEAs should be reduced by mechanical stirring to eliminate mass transfer limitations. Under these circumstances, 100 % recovery was obtained from both pure and crude tyrosinases. Optimum temperature and the activation energy for catechol oxidation were determined as 34 oC and 16.9 kcal/mol for CLEAs, whereas, 32 oC and 12.5 kcal/mol for the free enzyme. Furthermore, the thermostability of CLEAs was significantly higher than the free enzyme. CLEAs, prepared from crude mushroom extract, retained 72 % of its maximum activity in eight months storage at 4 oC. Moreover, changing the storage temperature from 4 oC to room temperature did not decrease CLEAs stabilities.
5

Aplicação de CLEA de β-amilase de cevada na produção de maltose a partir de amido residual do bagaço de mandioca em reator de fluxo em vórtices

Silva, Rafael de Araujo 31 March 2015 (has links)
Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-09-21T14:30:40Z No. of bitstreams: 1 DissRASac.pdf: 11251604 bytes, checksum: 6c180d000983f8c0f5a08597c2d53676 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-27T20:04:15Z (GMT) No. of bitstreams: 1 DissRASac.pdf: 11251604 bytes, checksum: 6c180d000983f8c0f5a08597c2d53676 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-27T20:04:24Z (GMT) No. of bitstreams: 1 DissRASac.pdf: 11251604 bytes, checksum: 6c180d000983f8c0f5a08597c2d53676 (MD5) / Made available in DSpace on 2016-09-27T20:10:13Z (GMT). No. of bitstreams: 1 DissRASac.pdf: 11251604 bytes, checksum: 6c180d000983f8c0f5a08597c2d53676 (MD5) Previous issue date: 2015-03-31 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Cassava is cultivated worldwide, being Brazil the fourth largest producer. The root industrial processing in the country, aiming to obtain mainly flour and starch, generates carbohydrate-rich residues (e.g., starch, cellulose, and hemicellulose), which could be used to produce value-added products by enzymatic route, mainly using immobilized enzymes that are more operationally stable, allowing to be easily recovered and reused in the process. Thus, this work aimed the biotransformation of residual starch from cassava processing in maltose, using immobilized β-amylase in a Couette–Taylor–Poiseuille vortex flow reactor, which can promote perfect mixture under lower shear stress in the reactional medium compared to the conventional stirred-tank reactor. Cassava bagasse and peel of two starch-processing industries from São Paulo State were physicalchemically characterized and showed about 47% and 55% (dry mass) of residual starch, respectively. The starch was enzymatically extracted from the residues using a α- amylase, followed by maltose production catalyzed by immobilized barley β-amylase. Among the immobilization methods studied in this work, the best one for β-amylase was protein aggregation using bovine serum albumin (BSA) or soybean protein (PS) as protein feeder, followed by cross-linking with glutaraldehyde (CLEA technique). This protocol yielded immobilized β-amylase with 82.67% and 53.26% of recovered activity, respectively. Besides, the CLEAs were highly stables at 40oC, retaining more than 80% of the initial activity after 12 hours. The maltose syrup production from starch was performed using a Couette–Taylor–Poiseuille vortex flow reactor, in order to evaluate the β-amylase CLEAs (in this case CLEA of β-amylase prepared with soybean protein, here named CLEA-β-PS). It was achieved around 70% of maltose conversion in a short reaction time (4 hours), showing that is viable the use of residual starch as raw material for the production of maltose catalyzed by β-amylase CLEA in a Couette–Taylor– Poiseuille vortex flow reactor. / A mandioca é cultivada em todo mundo, sendo o Brasil o quarto maior produtor. O processamento industrial da raiz no país visa principalmente à produção de farinha e fécula, gerando resíduos ricos em carboidratos (amido, celulose, hemicelulose) que poderiam gerar produtos de valor agregado por biocatálise enzimática, particularmente usando enzimas imobilizadas, por serem mais estáveis operacionalmente e poderem ser facilmente recuperadas e reutilizadas no processo. Assim, este trabalho teve como objetivo a biotransformação do amido residual dos resíduos do processamento da mandioca em maltose, usando a enzima β-amilase imobilizada em reator de fluxo em vórtices (RFV) Couette–Taylor–Poiseuille, reator este que pode promover mistura perfeita com menor tensão cisalhante no meio reacional, comparado a um reator de mistura perfeita convencional. Os resíduos bagaço e casca de mandioca de duas fecularias do interior de São Paulo foram caracterizados físico-quimicamente e apresentaram teores de amido por volta de 47% e 55% (b.s.), respectivamente. A extração do amido dos resíduos foi realizada enzimaticamente utilizando uma α-amilase, então, o amido liquefeito foi utilizado na produção de maltose catalisada pela β-amilase de cevada imobilizada. Dentre os métodos de imobilização estudados, o mais satisfatório para a imobilização de β-amilase foi a reticulação de enzimas agregadas (CLEA), utilizando albumina de soro bovino (BSA) ou proteína de soja (PS) como proteínas inertes, retendo 82,67% e 53,26% da atividade oferecida, respectivamente. Os CLEAs apresentaram estabilidades ao pH ligeiramente maiores que a β-amilase livre em seus respectivos valores de pH mais estáveis. Além disso, os CLEAs foram muito estáveis a 40ºC, retendo mais de 80% da atividade inicial após 12 horas de encubação. A conversão do amido em maltose foi realizada em um RFV, com a finalidade de estudar seu comportamento frente aos CLEAs de β-amilase (neste estudo CLEA de β-amilase preparado na presença de proteína de soja, aqui nomeado CLEA-β-PS). A conversão de amido em maltose foi de aproximadamente 70% em curto tempo de reação (4 horas), demonstrando a viabilidade do uso de amido residual como matéria-prima para a produção de maltose catalisada por CLEA de β-amilase em reator de fluxo em vórtices de Couette–Taylor–Poiseuille. Palavras chave: resíduos de mandioca, amido, maltose, beta-amilase de cevada, imobilização enzimática, CLEA, reator de fluxo em vórtices.
6

Mécanisme pour un développement propre (MDP) du protocole de Kyoto: barrières et opportunités pour les pays moins avancés d'Afrique :cas du Burundi

Bisore, Simon 12 September 2012 (has links)
Du Protocole de Kyoto est née une série d’objectifs de réduction des émissions de GES. Le respect de ces objectifs peut entraîner des coûts très lourds pour les économies des pays développés engagés dans la lutte contre les changements climatiques. Pour minimiser les coûts imposés par ces objectifs, des instruments économiques ont été développés, avec notamment la création de marchés du carbone. Y participent les trois mécanismes de flexibilité du Protocole de Kyoto parmi lesquels figure le Mécanisme pour un Développement Propre (MDP). <p><p>Parmi les problèmes posés par ce mécanisme de compensation, il y a des disparités observées dans la répartition géographique de sa mise en œuvre, alors qu’il est censé contribuer au développement de nombreux pays non-Annexe I. Parmi ceux-ci, les Pays les Moins Avancés (PMA) en général et ceux d’Afrique en particulier restent largement sous-représentés. Pourtant, le MDP a été adopté à la fois comme une contribution innovatrice à l’atténuation des changements climatiques et comme un moteur de promotion du développement durable dans les pays en développement.<p><p>Dans ce contexte, l’objectif général de cette thèse est triple. Primo, elle vise à étudier en profondeur cet instrument en dégageant ses principales caractéristiques, y compris les disparités d’implantation d’activités de projets qui lui sont liées. Secundo, elle en examine les causes par une analyse des barrières ou freins à la mise en œuvre d’activités de projets du MDP dans ces PMA d’Afrique en général et au Burundi en particulier. Tertio, elle révèle les opportunités (avantages/bénéfices) potentielles qui restent toujours non valorisées par l’implémentation d’activités de projets éligibles au titre du MDP.<p><p>L’analyse menée montre que les disparités susmentionnées jouent essentiellement en faveur des grands pays émergents d’Asie et d’Amérique latine, ce qui va à l’encontre du principe d’équité. En effet, en décembre 2011, le Brésil, la Chine et l’Inde détenaient 72,7 % de toutes les activités de projets du MDP et 75,8 % de crédits-carbone attendus en 2012. A l’opposé, les PMA ne disposaient dans le même temps que de 1,3 % de toutes les activités de projets du MDP et 1,2 % de leurs crédits attendus d’ici 2012. Les PMA d’Afrique ne restent qu’avec des parts de l’ordre de 0,8 % et 0,9 % respectivement. Cette situation reste si drastiquement critique qu’il importe d’en déceler les raisons.<p><p>Des caractéristiques de l’instrument, des expériences menées jusqu’ici et de la situation dans des pays hôtes, il ressort que les barrières sont de deux types. D’une part, les barrières endogènes, c'est-à-dire les barrières liées à l’organisation interne des pays. D’autre part, les barrières exogènes qui sont liées essentiellement à l’organisation générale du processus du MDP. L’étude a permis ainsi de montrer que les barrières endogènes constituent le nœud du problème en termes de visibilité des pays hôtes dans le marché du MDP. Celle-ci reste largement limitée dans ce marché international du carbone. <p><p>Les barrières identifiées dans ce travail, en particulier les barrières endogènes, risquent de se révéler difficiles à lever, car elles exigent des réformes structurelles au sein de l’organisation politique, institutionnelle, économique, et juridique du pays hôte. En outre, l’intégration de ces barrières dans un système unique d’interrelations constitue un des points originaux du travail. Ces interrelations ne sont pas négligeables et complexifient l’application du mécanisme, car, dans la plupart des cas, une action amorcée pour lever une barrière peut s’avérer inefficace si d’autres barrières associées ne sont pas prises en compte.<p>L’étude s’est également attachée à évaluer les retombées potentielles liées à la mise en œuvre d’activités de projets du MDP au Burundi. Les principales opportunités perdues jusqu’ici se situent dans quelques secteurs socioéconomiques du pays, essentiellement dans la gestion des déchets et l’énergie. L’étude en a ainsi retenu des options technologiques susceptibles de contribuer à des solutions à la problématique de la gestion des déchets et de l’approvisionnement énergétique au Burundi, tout en favorisant la stabilisation d’émissions de GES. Il s’agit de technologies adaptées de compostage et de bio-méthanisation dans le secteur de la gestion des déchets et les technologies de production d’énergies à partir de sources renouvelables (hydro, solaire, biogaz) et d’amélioration de l’efficacité énergétique de la biomasse (foyers améliorés, carbonisation) dans le secteur de l’énergie. <p><p>Ces opportunités ont également été analysées suivant des critères et indicateurs de durabilité (matrice de développement durable du Gold Standard). Les résultats montrent que ces options technologiques peuvent apporter une contribution au développement durable du pays. En effet, les opportunités se rencontrent à la fois dans le développement social (création d’emplois, moyens de subsistance des pauvres, accès aux énergies propres, renforcement des capacités), le développement écologique (réduction des émissions de GES, amélioration de la qualité de l’air, de l’eau et du sol, sauvegarde de la biodiversité), et le développement économique et technologique (rémunération d’emplois créés, augmentation des investissements, transfert et autonomie technologiques).<p><p>Afin de faire bénéficier le pays des retombées des activités de projets du MDP, il est proposé des solutions qui peuvent contribuer à une levée/atténuation de ces barrières. Ces propositions forment une combinaison d’actions à mener au niveau international, régional et surtout local/national. Au niveau international, des organes habilités devraient apporter des réformes profondes au MDP. Au niveau régional, le renforcement des capacités par des actions de coopération pourrait favoriser l’échange d’expériences en la matière. Au niveau local/national, l’adoption des réformes profondes aux niveaux institutionnel, législatif et juridique, dans une logique d’améliorer les politiques de planification du développement socioéconomique et environnemental, rendrait le pays naturellement plus attractif. En particulier, la mise en place et la mise en œuvre d’une stratégie nationale du MDP pourrait contribuer à relever le défi. <p><p>Les propositions de solutions pour réduire les barrières à la mise en œuvre d’activités de projets du MDP sont susceptibles de stimuler l’investissement en général. Ainsi, toute stratégie adoptée dans cette logique peut contribuer non seulement à la participation du pays au processus du MDP, mais aussi à favoriser la mise en œuvre d’autres projets conventionnels de développement au niveau national. Finalement, la considération de ces différentes opportunités associées à la mise en œuvre d’activités de projets du MDP au niveau du pays par des instances habilitées (décideurs politiques, acteurs institutionnels et économiques) conduirait à faire de ce mécanisme une contribution utile au développement du pays/The Kyoto Protocol has established a series of targets for reducing GHG emissions. The fulfilment of these objectives may result in heavy costs for the economies of developed countries engaged in the fight against climate change. To minimize the costs imposed by these targets, economic instruments were developed, notably with the creation of carbon markets. The three flexible mechanisms of Kyoto Protocol are involved in this, one of which being the Clean Development Mechanism (CDM). <p><p>Among the problems posed by this offset mechanism, disparities can be observed in regional distribution after it has been implemented, when it ought to be contributing towards the development of a number of Non-Annex I countries. Among these countries, the least developed ones (LDCs) in general and Africa ones in particular are largely under-represented. However, the CDM was adopted both as an innovative solution to mitigate climate change and as an engine to promote sustainable development in developing countries.<p><p>Within this context, the overall objective of this thesis is threefold. First of all, it aims to study this instrument in depth, by picking out its main characteristics, including the disparities in project activities implementation related to it. Secondly, it examines the causes for these disparities by analyzing the barriers or restrictions preventing implementation of CDM project activities in these African LDCs in general and in Burundi in particular. Its third purpose is to reveal the potential opportunities (advantages/benefits) which have yet to be developed by setting up eligible CDM project activities.<p><p>The analysis carried out shows that the aforementioned disparities come out in favor of the large emerging countries in Asia and Latin America primarily, which goes against the principle of equity. In fact, in December 2011, Brazil, China and India held 72.7% of all CDM project activities and 75.8% of carbon emission credits expected in 2012. On the contrary, for the same time period, the LDCs had only 1.3% of all CDM project activities and 1.2% of their carbon emission credits expected up until 2012. The African LDCs are left only with shares of 0.8% and 0.9% respectively. This situation is extremely critical. It is crucial to discover the reasons for it.<p><p>The instrument’s features, experiments carried out so far and the situation in host countries all reveal that the barriers fall into two categories. On the one hand, there are endogenous barriers, i.e. barriers related to the internal organization of countries. On the other hand, exogenous barriers are related to the general running of the CDM process especially. The study has thus revealed that the endogenous barriers are the crux of the problem where the presence of host countries is concerned in the CDM market. The visibility of host countries is rather limited in this international carbon market. <p><p>The barriers identified in this thesis, particularly endogenous ones, may be difficult to remove because they demand structural reforms in the political, institutional, economical and legal organization of the host country. In addition, the integration of these barriers into a single system of interrelationships is one of the original points of this thesis. These interrelationships are not insignificant and complicate the mechanism’s application, because in most cases, initiating an action to remove a barrier may be ineffective if other associated barriers are not taken into account.<p><p>The study has also focused on evaluating the potential impacts linked to the implementation of CDM project activities in Burundi. The main opportunities lost up to date are in some socioeconomic sectors in the country, particularly in the waste management and energy sectors. The study has therefore identified technological options that are likely to bring solutions to the question of waste management and energy supply in Burundi, while at the same time contributing to the stabilization of greenhouse gas emissions. These options are notably composting and anaerobic digestion technologies in the area of waste management, and energy generation technologies from renewable sources (hydro, solar, biogas) and improved energy efficiency of biomass (better households, carbonization) in the energy sector. <p> <p>These opportunities were also analyzed in accordance with sustainability criteria and indicators (Gold Standard sustainable development matrix). The results show that these technological options may contribute to sustainable development in the country. Indeed, the opportunities can be seen at the same time in social development (job creation, means of subsistence for the poor, clean energy access, capacity building); ecological development (reducing GHG emissions, improvement in quality of air, water and soil, preservation of biodiversity) and economic & technological development (better pay for jobs created, increased investment, technology transfer and technological autonomy).<p><p>In order to allow the country to take advantage of these opportunities through CDM project activities, it has been proposed solutions that can help raise/mitigate these barriers. These proposals are a combination of actions to be taken at international and regional levels and above all at a local/ national level. In the international arena, authorized bodies should make major reforms to the CDM. At a regional level, capacity building through joint actions could encourage the exchange of expertise in the field. Locally/nationally, adopting major reforms at institutional, legislative and legal levels, with a view to improving planning policies in socioeconomic and environmental development, would make the country naturally more attractive. In particular, establishing and implementing a national CDM strategy could also contribute towards taking up the challenge. <p><p>Proposals of solutions for mitigating barriers to implement CDM project activities are likely to stimulate investment in general. Thus, any strategy adopted along these lines can contribute not only to the country’s participation in the CDM process, but also to favoring implementation of other conventional projects for development at national level. Finally, considering these different opportunities associated with implementing CDM project activities in the country via authorized bodies (policymakers, institutional and economic actors) would lead to this mechanism being a useful contribution towards national development. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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