Made available in DSpace on 2015-03-26T13:52:01Z (GMT). No. of bitstreams: 1 01 - capa_abstract.pdf: 19961 bytes, checksum: e3e176ff7f15c76d6e02eb7f83656fdd (MD5) Previous issue date: 2007-03-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Propionic acid is an organic acid of three carbons that has been mainly used to preserve rations, grains and foods. Alternative strategies for application of propionic acid have been proposed, including their utilization in animal feeds. In this work, 38 bacteria were isolated from the bovine rumen and showed to produce organic acids using lactose from cheese whey. Only six isolates produced propionic acid, and the isolate named 22A showed the highest propionic acid production, and was selected for further study. The isolate 22A was a Gramnegative rod that utilized several carbon sources, including carbohydrates (glucose, lactose, maltose, sacarose, celobiose and mannose ), organic acids (lactate, piruvate, malate, fumarate and succinate) and glycerol. Regardless of the carbon source used, propionic acid was always the major fermentation end-product. Our results indicated that glycerol and succinate were the carbon sources that provided highest product yield and carbon recovery. Biomass production and product yield in mineral media were both affected by yeast extract concentration. When yeast extract (2 g/L) was added to the culture medium, the concentration of biomass and product formation increased about 270 % and 260 % respectively, compared to control treatments without yeast extract. The cultivation of the isolate 22A in diluted cheese whey (14 mM lactose) showed that the carbon source was being completely consumed after 16 hours of incubation and that the propionic acid yield and the acetate:propionato ratio were 2,37 mol/mol and 0,51, respectively. When increasing concentrations of lactose were added to the basal medium without pH contro1, a decrease in propionic acid yield and the appearance of other end-products was observed. Under these conditions, the pH of the culture medium decreased rapidly, reaching values of approximately 4,3 after 24 hours of incubation, for all the lactose concentrations tested. The control of pH in 6,8 using NaOH did not stimulate the production of propionic acid by isolate 22A, but lactose consumption increased to approximately 80 % in concentrations up to 338,70 mM. When isolate 22A was cultivated in basal medium with initial pH of 8,0 the specific growth rate and yield of propionic acid were 0,317 h-1 and 2,01 mol/mol, respectively. These results were better than those obtained at pH 7,0. These results indicated that isolated 22A has potential for propionic acid production in cheese whey. However, further work is needed to improve the cultivation system and to optimize the propionic acid yield. / O ácido propiônico é um ácido orgânico de três carbonos, e sua principal aplicação é como conservante de rações, grãos e alimentos. Estratégias alternativas de aplicação do ácido propiônico têm sido propostas, entre elas sua utilização na alimentação animal. Dentre as principais limitações para a produção fermentativa deste ácido orgânico estão o baixo rendimento e a baixa produtividade. Neste trabalho, foram isoladas 38 bactérias do rúmen bovino capazes de produzir ácidos orgânicos a partir da lactose do soro de queijo. Dentre estas, apenas o isolado 22A produziu ácido propiônico como principal produto da fermentação, sendo este selecionado para os experimentos Posteriores. O isolado 22A apresentou-se como bacilo Gram-negativo, capaz de metabolizar diversos açucares (glicose, lactose, maltose, sacarose, celobiose e manose ), ácidos orgânicos (lactato, piruvato, malato, fumarato e succinato) e glicerol, produzindo ácido propiônico como principal produto final da fermentação. Os resultados indicaram que glicerol e succinato foram às fontes de carbono que propiciaram maior rendimento os produto e recuperação de carbono. A produção de biomassa e o rendimento de produto em meio mineral foram afetados pela concentração de extrato de levedura no meio de cultivo. Quando 2 g/L de extrato de levedura foram utilizadas, a concentração de biomassa e o rendimento de produto aumentaram cerca de 270 % e 260 %, respectivamente, em relação ao controle sem extrato de levedura. O cultivo do isolado 22A em soro de queijo diluído (14 mM de lactose) indicou que a lactose foi completamente consumida após 16 horas de incubação e que o coeficiente de rendimento de produto para o ácido propiônico e a relação acetato/propionato foram 2,37 mol/mol e 0,51, respectivamente. Quando concentrações crescentes de lactose foram adicionadas ao meio basal sem controle de pH, observou-se a redução no rendimento de ácido propiônico e o aparecimento de outros produtos fmais na fermentação. Nestas condições, o pH do meio de cultura decresceu rapidamente, atingindo valores de aproximadamente 4,3 após 24 horas de incubação, para todas as concentrações de lactose testadas. O controle do pH do meio em 6,8 pela adição de NaOH não estimulou a produção de ácido propiônico pelo isolado 22A, mas observou-se consumo de aproximadamente 80% do substrato em concentrações de até 338,70 mM. O isolado 22A cresceu em meio basal com pH inicial de 8,0 e apresentou velocidade específica de crescimento de 0,317 h-1 e rendimento de ácido propiônico de 2,01 mol/mol. Esses resultados foram superiores aos obtidos com o isolado 22A quando cultivado em pH 7,0. Os resultados deste trabalho indicam que o isolado 22A possui potencial para produção de ácido propiônico em soro de queijo. Entretanto, outros estudos deverão ser realizados para a adequação do sistema de cultivo e a otimização do rendimento de produto.

Made available in DSpace on 2017-07-21T18:53:21Z (GMT). No. of bitstreams: 1 Debora C Moreira.pdf: 799615 bytes, checksum: bf5390535b39bc8ca4f452bde2fd297b (MD5) Previous issue date: 2013-07-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The search for renewable energy and food production with the minimum threat to the environment are themes that have been studied for all over the world. Several processes have been developed for the use of agroindustrial wastes, transforming them into chemical compounds and products with high added value. The use of agroindustrial wastes in bioprocesses helps the search for sustainable processes. The increasing in the agricultural productivity in Brazil, open a new market to the development of researches that study this issue. The statistical modeling of mixtures, allied with the design of experiments, has application in a several industrial systems. The aim of this work was to study the possibility of use agroindustrial wastewater mixtures to produce propionic acid. Four types of wastewater were studied: corn steep liquor, pet food wastewater, meat processing wastewater and dairy wastewater. Assays were performed to obtain the best composition of the mixtures and the best substrate ratio. Within the conditions employed, the mixture containing 75% of corn steep liquor and 25% of another substrate, were most suitable for the process. Studying the tests in which the fermentations conditions varied (boiling the substrate, agitation and pH correction to 6,5) the best concentrations of propionic acid, 229,57 mg.L-1, were produced by mixing 75% of corn steep liquor and 25% of pet food wastewater, after 72h of fermentation, with initial correcting of pH to 6,5, followed by the mixture containing 75% of corn steep liquor and 25% of meat processing wastewater, that enabled the production of 154,27 mg.L-1 of propionic acid. The mixture with 75% of corn steep liquor and 25% of dairy wastewater with daily pH correction enabled the production of 220,96 mg.L-1 of propionic acid after 72 hours of fermentation. The other essay conditions were not significant for propionic acid biosynthesis. The statistical analysis confirms that it is possible to use codigestion agroindustrial waste for propionic acid production. / A busca por fontes de energia renovável e a produção de alimentos com a mínima ameaça ao ecossistema têm sido temas bastante pesquisados em todo o mundo. Diversos processos têm sido desenvolvidos para a utilização de resíduos agroindustriais, transformando-os em compostos químicos e produtos com alto valor agregado. A utilização de resíduos agroindustriais em bioprocessos favorece a busca por processos sustentáveis. O aumento da produtividade agrícola no Brasil abre um novo mercado para o desenvolvimento de pesquisas que abordem este tema. O planejamento estatístico de misturas, aliado à otimização de experimentos, tem aplicação em diversos sistemas industriais. O objetivo deste trabalho foi avaliar a possibilidade da utilização de misturas de efluentes agroindustriais para a produção de ácido propiônico. Foram utilizados quatro tipos de efluentes: efluente do processamento de milho, efluente do processamento de ração animal, efluente de processamento de carnes e de laticínio. Foram realizados ensaios para a obtenção da melhor composição das misturas, definindo-se a melhor proporção dos substratos. Dentro das condições empregadas, as composições contendo 75% do efluente do processamento de milho e 25% de outro substrato foram as mais adequadas ao processo. Nos ensaios onde as condições de fermentação foram variadas (fervura prévia do substrato, agitação e correção do pH para 6,5), os melhores resultados de produção de ácido propiônico, 229,57 mg.L-1, foram obtidos com substrato composto por 75% de efluente do processamento de milho mais 25% de efluente de fábrica de ração, com 72h de fermentação, correção de pH inicial para 6,5 e sem agitação, seguido de substrato com 75% de efluente do processamento de milho mais 25% de efluente de processamento de carnes, nas mesmas condições, obtendo-se produção de 154,27 mg.L-1 de ácido propiônico. O substrato contendo 75% de efluente do processamento de milho mais 25% de efluente de laticínio, possibilitou produção de 220,96 mg.L-1 de ácido propiônico, após 72 horas de fermentação e com correção de pH a cada 24 horas. As outras condições testadas não foram significativas na biossíntese de ácido propiônico. A análise estatística dos dados confirmou que é possível a utilização de codigestão de efluentes agroindustriais para a produção de ácido propiônico.

Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-09-30T18:55:37Z No. of bitstreams: 1 DissTCN.pdf: 1750863 bytes, checksum: 7f270955d14599a5df96c67c05642037 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-30T19:05:44Z (GMT) No. of bitstreams: 1 DissTCN.pdf: 1750863 bytes, checksum: 7f270955d14599a5df96c67c05642037 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2016-09-30T19:05:52Z (GMT) No. of bitstreams: 1 DissTCN.pdf: 1750863 bytes, checksum: 7f270955d14599a5df96c67c05642037 (MD5) / Made available in DSpace on 2016-09-30T19:11:43Z (GMT). No. of bitstreams: 1 DissTCN.pdf: 1750863 bytes, checksum: 7f270955d14599a5df96c67c05642037 (MD5) Previous issue date: 2015-04-24 / Fundação de Amparo à Pesquisa do Estado do Amazonas (FAPEAM) / This study aimed to produce propionic acid, 1,3-propanediol and hydrogen in anaerobic fluidized bed reactor with grounded tire as support material for immobilization of biomass. The experiment took place during 278 days in six distinct phases distributed according to the hydraulic retention time (HRT), which ranged between 8 and 0.5 h. The reactor was maintained at mesophilic conditions (30 ° C) with controlled pH between 4.5 and 5.5 and crude glycerol as carbon source at a concentration of 5 g L-1. The inoculum used in the experiment was derived from the processing of poultry slaughterhouse wastewater station. The results show that the consumption of substrate conversion reached the highest value (89.8 %) in HRT of 6 hours. The biogas produced was composed of H2 and CO2 and the greatest recorded content of H2 has been reached (81.2%) in HRT of 4 hours. The principal soluble metabolite produced were propionic acid and 1,3-propanediol, with maximum yields of 1,77 and 0,82 mol.molglicerol -1, respectively. Both maximum yields were achieved in HRT of 8 h. At all stages of this work occurred predominantly propionic acid, with maximum molar percentage (96,9 %) achieved in HRT of 0,5 h. The second predominant metabolite obtained was 1,3- propanediol, achieving greater molar percentage (29.4%) in HRT of 6 hours. / O presente trabalho teve por objetivo produzir ácido propiônico, 1,3-propanodiol e hidrogênio em reator anaeróbio de leito fluidizado com pneu triturado como material suporte para adesão da biomassa. O experimento ocorreu durante 278 dias, em seis fases distintas distribuídas em função do tempo de detenção hidráulica (TDH), que variou entre 8 e 0,5 h. O reator foi mantido em condições mesofílicas (30 °C), com pH controlado entre 4,5 e 5,5 e possuía glicerol bruto como fonte de carbono na concentração de 5 g L-1. O inóculo utilizado no experimento foi proveniente de estação de tratamento de efluente de abatedouro de aves. Os resultados obtidos mostram que o consumo de substrato atingiu o maior valor de conversão (89,8 %) no TDH de 6 h. O biogás produzido foi composto de H2 e CO2, tendo o maior conteúdo de H2 registado (81,2 %) no TDH de 4 h. Os principais metabólitos solúveis obtidos foram ácido propiônico e 1,3-propanodiol com rendimentos máximos de 1,77 e 0,82 mol.molglicerol -1, respectivamente. Ambos os rendimentos máximos foram atingidos no TDH de 8 h. Em todas as fases apresentadas, ocorreu a predominância de ácido propiônico, sendo a maior porcentagem molar (96,9 %) atingida no TDH de 0,5 h. O segundo metabólito mais produzido foi o 1,3-propanodiol, alcançando maior porcentagem molar (29,4 %) no TDH de 6 h.

Actuellement produit à partir du pétrole, une voie de synthèse de l'acide acrylique (AA) à partir du glycérol est envisagée. Cependant, cet AA bio-sourcé contient davantage d'acide propionique (AP) que l'AA issu du propylène. Les techniques classiques de purification ne permettent pas de séparer les deux acides. Le diagramme de phases liquide-solide du binaire AA + AP est déterminé. Il présente un point eutectique à 25,65 % (mol) d'AA, un point péritectique à 50,00 % (mol) d'AA et donc, un large domaine dans lequel l'AA cristallise thermodynamiquement de façon pure. Les essais de purification en mode statique sur paroi froide affichent des résultats prometteurs, une efficacité de séparation correcte pour un rendement de 60 %. Afin d'améliorer les transferts de matière et de chaleur, des dispositifs en mode dynamique sont mis au point dont un cristallisoir en film tombant. Ce dispositif permet de multiplier par 2,8 la productivité, tout en conservant une bonne efficacité de séparation. Afin de diminuer la surfusion et de maintenir un bon transfert thermique malgré une couche cristalline relativement isolante, des surfaces de cristallisation micro- et milli-structurées sont envisagées. La productivité est encore améliorée et la modélisation du transfert thermique confirme ces résultats expérimentaux. Afin de se rapprocher des conditions industrielles, un brut synthétique de bio-AA est purifié. La cristallisation en milieu fondu permet de séparer toutes les impuretés testées. Enfin, un modèle de cascade de cristallisoirs fermés, avec recyclage des différentes phases, est proposé afin de dimensionner le procédé global. Les essais en conditions presque réelles et l'intensification du procédé de cristallisation permettent d'envisager sereinement la mise en oeuvre du procédé industriel / With a global market exceeding four million tons per year, acrylic acid (AA) is a major intermediate chemical. The current AA synthesis is based on propylene, which is produced from oil. Thus, a novel production route is envisioned, based on glycerol, a green byproduct of oleochemistry and biodiesel production. However, current crude biobased AA contains a higher proportion of PA than AA from petrochemical origin. Classical purification techniques of AA cannot efficiently separate these two chemicals. In a first part, liquid-solid phase diagram of the binary system AA + PA is determined. This liquid-solid equilibrium exhibits an peritectic behavior at 50.0% (mol) of AA, a eutectic point at 25.65% (mol) of AA and thus, this diagram is favorable to the purification of AA. First purification tests by static solid layer melt crystallization show promising results: a correct separation efficiency for a yield varying between 60 et 70 %. To improve heat and mass transfer, dynamic crystallization set-up are developed, including a falling film crystallizer. This set-up multiplies by 2.8 the productivity of purification, while keeping a good separation efficiency. To reduce supercooling and to keep a good heat transfer despite the crystalline layer which is a thermal insulator, micro-and milli-structured crystallization surface are considered. Productivity is further improved and heat transfer modeling confirms the experimental results. To be nearer to industrial conditions, synthetic crude bio-AA is purified. Melt crystallization can separate all the impurities which are present in the medium. To scale-up the overall process a cascade model of batch crystallizers with recycling of the differents phases, is proposed. The intensification of the melt crystallization process permits to consider the implementation of the industrial process

The goal of this work was to synthesize complex macromolecular architectures such as dendrimers and dendronized polymers, and evaluate the effect from the dendrons on the optical and material properties. The work presented in this doctoral thesis, Dendrimers and Dendronized Polymers - Synthesis and Characterization, is divided into one minor and one major part. The first part deals with the synthesis and characterization of two sets of dendritic porphyrins based on 2,2-bis(methylol)propionic acid (bis-MPA). The second part deals with the synthesis and characterization of dendronized poly(hydroxyl ethyl methacylate), dendronized poly(norbornene), and dendronized triblock copolymers, were the pendant dendrons are based on bis-MPA. Both free-base and zinc containing dendritic porphyrins was synthesized up to the fifth generation by employing iterative ester coupling utilizing the acetonide protected anhydride of bis-MPA as generic building block. First and second generation dendron bearing methacrylates based on 2-hydroxyethyl methacrylate were also synthesized by utilizing the acetonide protected anhydride of bis-MPA, and subsequently polymerized by atom transfer radical polymerization. By adopting a divergent “graft-to” approach starting from the first generation dendronized poly(hydroxyl ethyl methacrylate), well-defined dendronized polymers with acetonide, hydroxyl, acetate and hexadecyl surface functionality were obtained. By utilizing the same divergent iterative esterfication, first to fourth generation dendron functionalized norbornenes were synthesized. These monomers were polymerized by ring-opening metathesis polymerization, utilizing either Grubbs´ first or second generation catalyst. Acrylate functional first to fourth generation monomers were synthesized by the copper(I) catalyzed “click” coupling of azido functional dendrons and propargyl acrylate. The monomers were polymerized to dendronized triblock copolymers by reversible addition-fragmentation chain transfer polymerization, utilizing a difunctional poly(methyl methacrylate) as macro chain transfer agent. The bulk properties of the dendronized poly(hydroxyl ethyl methacrylate) and poly(norbornene) were investigated by dynamic rheological measurements and differential scanning calorimetry. It was found that all the acetonide functional bis-MPA based dendronized polymers had glass transitions temperatures in a similar range. The rheological behaviour showed that for the dendronized polymers having the same backbone length the complex viscosity as a function of functionality was independent of the surface functionality of the polymer. The generation number of the polymer had a profound influence on the complex viscosity, changing form a Newtonian behaviour to a shear thinning behaviour when the generation of the dendrons was increased from two to four. The dendronized poly(norbornene) had increasingly shorter backbone lengths for each generational increase, and for the materials set with comparably lower degree of polymerization, the G’ part of the complex modulus was mostly affected by attaching larger dendrons. In the case of the sample set of higher degree of polymerization, the second, third, and fourth generation samples had similar slopes of the G’ and G” curves, indicating a similar relaxation behaviour. / QC 20100914