Não consta resumo na publicação. / Abstract not available.

Os efeitos do fornecimento de dietas contendo glicerina bruta foram avaliados em quatro experimentos com ovinos de diferentes categorias. Experimento 1: Quarenta cordeiros foram usados para avaliar os efeitos da inclusão de glicerina bruta sobre o desempenho, as características de carcaça e da carne e a concentração de enzimas hepáticas. As rações experimentais foram isonitrogenadas, sendo que o ajuste proteico foi realizado pela inclusão de ureia e farelo de soja. Os teores de inclusão de glicerina bruta foram: 0, 5, 10 ou 15% na MS. A adição de glicerina bruta causou efeito quadrático no CMS, CFDN, CPB, GMD e peso final. A inclusão de glicerina causou efeito quadrático para peso corporal ao abate, PCQ e PCF. Foi observado efeito quadrático para os ácidos graxos mirístico, palmítico, palmitoleico, linoleico e rumênico. A glicerina bruta demonstrou ser um bom substituto do milho em dietas com alto teor de concentrado, melhorando o desempenho e as características da carcaça dos animais quando incluída até 10% na MS. Experimento 2: Cinquenta cordeiros(as) foram usados para avaliar os efeitos da inclusão de glicerina bruta em rações com alta proporção de concentrado, sobre o desempenho, características de carcaça e parâmetros enzimáticos. As rações experimentais foram isonitrogenadas, sendo o ajuste proteico realizado pela inclusão de farelo de soja. Os teores de inclusão de glicerina bruta foram: 0, 5, 10, 15 e 20% na MS. A inclusão de glicerina bruta não afetou as variáveis de desempenho analisadas. Houve apenas efeito linear para o CMM. A glicerina bruta pode substituir o milho em até 20%, mantendo o desempenho dos animais e as características de carcaça. Experimento 3: Cinco borregos canulados no rúmen foram utilizados para avaliar os efeitos da glicerina bruta sobre os parâmetros ruminais, a digestibilidade das dietas e o metabolismo de nitrogênio. As dietas foram isonitrogenadas e os teores de inclusão de glicerina bruta foram: 0, 5, 10, 15 ou 20% na MS. Houve redução linear na ingestão de FDN e aumento linear na ingestão de MM. Houve efeito linear crescente para a digestibilidade da MS e MO. A inclusão de glicerina bruta causou redução linear no acetato, relação C2:C3, AGCC total, e aumento linear no pH ruminal. A glicerina bruta pode substituir até 20% do milho em dietas de borregos, melhorando a digestibilidade da MS e MO. Experimento 4: Cento e dezoito ovelhas com 90 dias de prenhez foram utilizadas para avaliar a inclusão de glicerina bruta em dietas de gestação e lactação. Os teores de inclusão foram 0 ou 10%. Da segunda a oitava semana foi mensurado o CMS e produção de leite das ovelhas e a ingestão de concentrado inicial dos cordeiros. A inclusão de glicerina bruta aumentou o CMM e reduziu a porcentagem de gordura no leite. A adição da glicerina bruta na dieta das ovelhas diminuiu a concentração sérica de AGNE. A inclusão de 10% de glicerina bruta na dieta de ovelhas durante a gestação e lactação não prejudica o desempenho dos animais e reduz a possibilidade de ocorrência de toxemia da gestação. / The effects of feeding diets with crude glycerin were evaluated in 4 trials using different categories of sheep. Experiment 1: Forty Santa Inês ram lambs were used to determine the effects of partial replacement of corn by crude glycerin on growth, hepatic enzymes, carcass and meat characteristics of lambs fed high-concentrate diets. The diets were isonitrogenous and the protein was adjusted by increasing urea and soybean meal. Increasing levels of crude glycerin were: 0, 5, 10 or 15%. There was quadratic effect for DMI, NDFI, CPI. ADG and final weight. There was a quadratic effect for slaughter BW and dressing percentage, but no difference on longissimus muscle area, backfat thickness and body wall thickness. There was quadratic effect for myristic, palmitic, palmitoleic, linoleic and rumenic acid. Crude glycerin is a good substitute of corn in high-concentrate diets, improving performance and carcass characteristics when included until 10% of the diet DM. Experiment 2: Fifty lambs were used to determine the effects of partial replacement of corn by crude glycerin on growth, carcass characteristics and hepatic enzymes of lambs fed high concentrate diets. The diets were isonitrogenous and the protein adjusted was performed with increased soybean meal. Increasing levels of crude glycerin were: 0, 5, 10, 15 or 20%. There was an increased in mineral matter intake. Crude glycerin can be used as a substitute for corn in high concentrate diets of ram lambs without affecting performance and carcass characteristics. Experiment 3: Five Santa Inês ram lambs, cannulated in the rumen, were used to determine the effects of using crude glycerin on ruminal constituents, diet digestibility and nitrogen metabolism. The diets were isonitrogenous and crude glycerin was included in the ration at 0%, 5%, 10%, 15% or 20% in the DM. There was linear decreased on NDF intake and a linear increase in ash intake. Feeding crude glycerin increased DM and OM digestibility. Crude glycerin decreased acetate, acetate:propionate ratio, total SCFA and showed a linear increase on pH. Replacing corn by crude glycerin up to 20% of dietary DM increased DM and OM digestibility, maintained propionate and decreased acetate and total SCFA. When soybean meal was used to adjust the diet protein level, there were no changes on nitrogen metabolism. Experiment 4: One hundred and eighteen 90 d pregnant ewes were used to determine the effects of feeding crude glycerin on performance, NEFA concentration and lamb growth. Diets were isonitrogenous and crude glycerin levels were zero or 10%. From the second until de eighth week of lactation DM intake of the ewes and starter of the lambs were measured. There was an increase on ash intake for the glycerin fed ewes. There was a decrease in milk fat percentage. Crude glycerin fed ewes showed a decrease on blood NEFA. The inclusion of 10% of crude glycerin in the diets of sheep during pregnancy and lactation had no detrimental effect on performance of ewes and lambs. Using 10% of crude glycerin decreases the chances of pregnancy toxemia in ewes.

O nitrogênio desempenha função essencial na fisiologia das leveduras e em fermentações com alta concentração de açúcares propicia maior rendimento, eficiência e produtividade, além de proteger as células de levedura dos estresses osmóticos provocados pelas altas concentrações de açúcar e de etanol. Com o objetivo de verificar a influência da suplementação nitrogenada nos parâmetros fermentativos, mostos contendo caldo de cana concentrado a 25, 30 ou 35° Brix e suplementados ou não com ureia (16 mM) ou fosfato de amônio (24 mM), foram fermentados a 30°C por leveduras Saccharomyces cerevisiae (linhagens PE-2 ou CAT-1) em 6 ciclos consecutivos de 24h. Ao final de cada ciclo, foram analisados: a massa úmida (biomassa) por pesagem após a centrifugação; a viabilidade celular pelo método de coloração com eritrosina e a concentração de etanol em densímetro digital (Anton Paar DMA 4500), após destilação das amostras por arraste de vapor em destilador Tecnal TE-012 e açúcar por cromatografia líquida (HPLC). A concentração de nitrogênio total utilizável foi determinada pelo método da ninidrina, utilizando glicina como padrão. Em mosto contendo 30°Brix, a linhagem CAT-1, produziu teores de etanol, em média, de 12,9, 17,1 e 14,4% (v/v), respectivamente, nos tratamentos controle (T1) ou suplementado com ureia (T2) ou fosfato (T3). Nesta condição, a linhagem PE-2, produziu 14,9 (T1), 15,8 (T2) e T3 15,8% (v/v) e a massa úmida da CAT-1 aumentou de 7% para 16%, na presença de fosfato. Na fermentação do mosto 35°Brix, pelas duas linhagens, a suplementação com fosfato (T3) propiciou maior produção de etanol, aumento de massa úmida e manutenção da viabilidade celular. A levedura CAT-1, no tratamento com 30° Brix, produziu mais glicerol no tratamento com fosfato de amônio sendo quase 1g de glicerol por cada 1g de biomassa produzida. A suplementação com ureia teve efeitos benéficos na fermentação VHG possibilitando uma produção maior de etanol, e uma produção menor de glicerol face às outras suplementações nitrogenadas. / Nitrogen plays an essential role in the physiology of yeast and fermentation of high concentration sugars. It provides higher yield, efficiency and productivity, as well as protects yeast cells from osmotic stress caused by high concentrations of sugar and ethanol. To evaluate the influence of nitrogen supplementation on fermentative parameters, must containing concentrated sugarcane juice to 25, 30 or 35°Brix and supplemented or not with 16 mM urea or 24 mM ammonium phosphate were fermented at 30°C by PE-2 or CAT-1 yeast strains of Saccharomyces cerevisiae into 6 consecutive cycles of 24h. At the end of each cycle, cell viability by staining with erythrosine method, wet mass (biomass) by weighing; and the ethanol concentration in digital densitometer, after samples distillation were analyzed. The concentration of total usable nitrogen was determined by the ninhydrin using glycine as standard. In 30°Brix wort, CAT-1 strain produced averaged 12.9, 17.1 and 14.4% (v/v) of ethanol concentration, respectively, in the (T1) control or with (T2) urea or (T3) phosphate supplemented treatments. In this condition, the PE-2 strain produced 14.9 (T1), 15.8 (T2) and T3 15.8% (v / v) and the wet weight of CAT-1 increased from 7% to 16%, in the presence of phosphate. In the fermentation of the must 35°Brix by the two strains, supplementation with phosphate (T3) led to increased ethanol production, increased wet weight and maintenance of cell viability. CAT-1 strain, in 30°Brix, produced more glycerol upon treatment with ammonium phosphate being about 1 g glycerol per 1 g of biomass produced. Supplementation with urea had beneficial effects on VHG fermentation enabling increased production of ethanol, and a lower production of glycerol against other nitrogen supplementation.

A busca por embalagens flexíveis rapidamente degradáveis tem sido intensa nos anos mais recentes. Amidos de variadas fontes têm sido avaliados para a produção de filmes, sendo que a maioria destes apresenta boas características mecânicas e de barreira ao oxigênio, entretanto, uma série de limitações é observada com relação às suas características hidrofílicas e permeabilidade ao vapor d´água. O amido de ervilha normalmente apresenta teores mais elevados de amilose, o que pode melhorar a obtenção da rede formadora de filmes. Além disto, as associações amido-goma podem modificar a gelatinização e retrogradação do amido, processos que interferem na formação de filmes. O acréscimo de plastificantes também tem se mostrado de importância para melhorar as propriedades mecânicas dos filmes. Assim, o objetivo do presente trabalho foi avaliar o efeito da adição de goma xantana e de glicerol ao amido de ervilha verde de alto teor de amilose (cv. Utrillo) na elaboração de filmes e em suas características. Soluções filmogênicas (SF) com diferentes teores de amido de ervilha (3, 4 e 5%), de goma xantana (0, 0,05 e 0,1%) e de glicerol (proporção glicerol-amido de 1:5 p/p) foram estudadas. As SF foram obtidas por ebulição (5 min.), seguida de autoclavagem por 1h. a 120°C. Os filmes foram prepa rados segundo a técnica de casting. O aumento da concentração de amido na solução filmogênica aumentou a espessura, fator de ruptura, resistência à perfuração e solubilidade dos filmes em água. O aumento da concentração da goma xantana interferiu apenas nas propriedades associadas à cor dos filmes, aumentando os valores da tonalidade e decrescendo o croma a* e a transparência. O aumento da concentração do glicerol interferiu nas propriedades mecânicas dos filmes, gerando redução dos valores de resistência máxima à tração, tensão na ruptura, resistência à perfuração e fator de ruptura. O plastificante também gerou aumento do alongamento na ruptura, redução da transparência e aumento da espessura e da solubilidade do filme em água. / In the past few years, the attempt to obtain degradable flexible packaging has increased considerably. In this sense, starches obtained from different botanical sources have been evaluated to produce films. Most of these films present good mechanical characteristics and provide a good barrier to oxygen. Nevertheless, some limitations have been observed in relation to their hydrophilic properties and permeability to water vapor. Studies using starch from green peas with high levels of amylose to produce films were not found in the literature. The higher levels of amylose can improve the achievement of the matrix that forms films. In addition, starch-gum associations can modify starch gelatinization and retrogradation, processes which interfere with film formation. The addition of plasticizers has also been considered important to improve the mechanical properties of films. The aim of this study was to evaluate the effect of the addition of xanthan gum and glycerol to the starch of green peas with high content of amylose (cv. Utrillo) in the preparation of films and in their features. Filmogenic solution (FS) with different levels of pea starch (3, 4 and 5%), xanthan gum (0, 0.05 and 0.1%) and glycerol (glycerol-starch ratio of 1:5 p/p) were tested. The FS was obtained by boiling (5 min.), followed by autoclaving for 1h. at 120°C. The films were prepared by casting. The increased concentration of starch in the solution increased the thickness, factor of rupture, puncture force and solubility of films in water. Increasing amounts of xanthan affected only the properties associated with the color of the films, increasing the values of hue angle and decreasing the chroma a* and transparency. The increased concentration of glycerol interfered in the mechanical properties of the films, causing reduction of the maximum values of tensile strength, strain at break, puncture force and factor of rupture. The plasticizer also caused an increase of elongation at break, reduced transparency and increased thickness of the film and the solubility in water.

Leveduras oleaginosas possuem a capacidade de sintetizar grande quantidade de lipídeos em suas células, gerando produtos de alto valor agregado através de um processo sustentável. Um perfil de ácidos graxos poli-insaturados é de grande interesse por parte das industrias alimentícia e farmacêutica e têm sido alvo de diversos estudos em relação à sua produção e efeitos benéficos à saúde. O presente trabalho teve como objetivo produzir ácidos graxos poli-insaturados pela levedura Meyerozyma guilliermondii BI281 utilizando glicose, glicerol residual e permeado de soro de queijo como fontes de carbono. Avaliou-se o metabolismo da levedura em meios de cultivo com diferentes composições (“meio A” e “base YM”) e comparou-se o seu desempenho em razões C/N 100: 1 e 50:1. A levedura foi capaz de metabolizar todos os substratos testados e o meio de cultivo “A” com glicerol residual e razão C/N 50:1 mostrou-se o mais adequado, obtendo valores de 5,67 g.L-1 de biomassa e 1,04 g.L-1 de lipídeos, representando aproximadamente 18 % do peso da massa seca de biomassa. Esta condição foi escalonada para biorreator de 2 L, onde condições de aeração e controle de pH puderam ser avaliadas, apresentando quantidade semelhante de lipídeos (1,08 g.L-1) e uma maior produção de biomassa (7,05 g.L-1). Os ácidos graxos sintetizados apresentaram em sua composição ácido láurico (C12:0), ácido mistírico (C14:0), ácido palmítico (C16:0), ácido pamitoleico (C16:1), ácido esteárico (C18:0), ácido oleico (C18:1 n-9), ácido linoleico (C18:2 n-6) e ácido linolênico (C18:3 n-3). / Oleaginous yeasts are able to synthesize high amounts of lipids in their cells, producing high added-value products through a sustainable process. Food and pharmaceutical companies have great interest in polyunsaturated fatty acids depending on their profiles and many studies related to their production and health benefits have been carried out. The aim of this study was to produce polyunsaturated fatty acids by the yeast Meyerozyma guilliermondii BI281A using glucose, crude glycerol, and cheese whey permeate as carbon sources. Yeast metabolism was evaluated in different compositions of culture media (“A” and “YM”) and at different C/N ratios (100:1 and 50:1). The yeast was able to assimilate all substrates tested, and medium “A” with crude glycerol as carbon source at a C/N ratio of 50:1 had the most efficient result with biomass production of 5.67 g.L-1 and lipid production of 1.08 g.L-1, which represented 18 % of dry cell weight. This composition was scaled-up to a 2 L bioreactor, where it was possible to measure pH and aeration conditions, and showed similar lipid production (1.08 g.L-1) and higher biomass production (7.05 g.L-1). Fatty acids profile obtained was composed by lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid(C18:1), linoleic acid (C18:2 n-6), and linolenic acid (C18:3 n-3).

The T cell receptor (TCR) activation induced signaling cascade is a major driver of T cell effector responses such as cytokine production and actin cytoskeletal rearrangement. Characterizing chemical modulators of this pathway has the benefits of both revealing basic science knowledge about these signaling processes and providing foundation for development of novel therapeutics. Glycerol Monolaurate (GML) is a naturally occurring fatty acid monoester that is found as a monoglyceride in human breast milk and coconut oil. It is widely utilized in food, cosmetics, and homeopathic supplements. GML is a potent antimicrobial agent that targets a wide range of bacteria, fungi, and enveloped viruses. Because of this, GML has been developed as a preventative for menstrual associated Toxic Shock Syndrome, and is being tested to prevent HIV transmission and superficial skin infections. Interestingly, GML suppresses mitogen induced lymphocyte proliferation and inositol triphosphate production, suggesting that GML has immunomodulatory functions. This thesis mechanistically examined how GML affects human primary T cells. Chapter III describes how GML potently altered order and disorder dynamics in the plasma membrane that resulted in reduced membrane-localized clustering of the proteins LAT, PLC-γ, and AKT, events integral for proper TCR signal propagation. Altered membrane signaling events induced selective inhibition of TCR-induced signaling events. Specifically GML reduced the phosphorylation of the regulatory P85 subunit of PI3K, and AKT and abrogated calcium influx. Functionally, GML treatment potently reduced TCR-induced production of the cytokines IL-2, IFN-γ, TNF-α, and IL-10. Chapter V shows that GML causes the mis-localization of the ARPC3 subunit of the Arp2/3 complex that leads to the formation of abnormal filopodia structures, and reduced cellular adhesion. Chapter V shows that human serum albumin binds directly to GML on the 12 carbon acyl chain. This interaction reverses GML induced suppression of TCR-induced formation of LAT, PLC-γ1, and AKT microclusters at the plasma membrane, AKT phosphorylation, and cytokine production. These findings establish GML as a T cell suppressive agent in addition to an antimicrobial agent. This observation reveals the potential role of naturally occurring GML in human breast milk in the formation of microbiota and immune tolerance in the infant gastrointestinal tract. It also allows for optimization of the current applications of GML in various commercial products and therapeutic strategies. Finally this information provides the rationale to investigate GML in new remedial avenues as a topical agent to treat excessive inflammation in the skin, and vaginal and gut mucosal regions.

Le défi de cette thèse est d’utiliser le glycérol, co-produit de la production de biodiesel, pour synthétiser des molécules ayant des propriétés lubrifiantes en restant dans le cadre d’une chimie verte. Cette étude porte sur l’éthérification en deux étapes du glycérol par un alcool par catalyse acide. Les objectifs principaux de ce projet sont donc la synthèse et la purification de mono-, di- et tri-éthers de glycérol (MEG, DEG, TEG), ainsi que l’étude des relations entre leurs structures et leurs propriétés pour des applications lubrifiantes. Les propriétés tribologiques de ces molécules comme modificateurs de frottements pour les lubrifiants ont été évaluées au Centre de Recherches de Solaize (CReS).La formation d’éthers de glycérol par des alcools a déjà été largement étudiée dans la littérature. Pour contourner le problème d’immiscibilité entre le glycérol et les alcools gras, la première éthérification a été réalisée avec un alcool court (6 carbones) et la seconde avec un alcool long (>7 carbones), les mono-éthers de glycérol étant miscibles avec les alcools gras. Ainsi la formation de MEG et DEG avec plus de vingt carbones est rendue possible. Dans ce travail, les paramètres de réaction (ratio entre les réactifs, nature et quantité de catalyseurs, purification) ont été optimisés pour deux réactions modèles. La première réaction est l’éthérification entre le glycérol et le 1-hexanol, et la seconde, l’éthérification entre le mono-hexyl de glycérol obtenu et le 1-hexanol. Une des difficultés principales de ces réactions est la séparation et la purification des différents éthers obtenus, à cause notamment de leurs structures très proches, ainsi que de la présence de sous-produits tels que des oligomères de glycérol. L’optimisation du procédé de purification des produits a donc représenté un des volets importants de cette thèse. Les meilleures conditions de purification déterminées ont permis d’extraire 80% du mono-hexyl éther de glycérol synthétisé du milieu réactionnel brut. L’optimisation des conditions opératoires et de la purification ont permis d’étendre l’éthérification du glycérol à plusieurs autres alcools de structures différentes. Par cette méthode, dix-huit échantillons de mono et/ou di-éthers de glycérol différents ont été obtenus. Chacun de ces échantillons a été testé au Centre de Recherches TOTAL de Solaize en tant qu'additifs modificateurs de frottements pour les lubrifiants. Ces tests ont permis d’établir des corrélations entre la structure chimique des molécules et leurs propriétés tribologiques. / The challenge of this PhD is to use glycerol, by-product of biodiesel production, to generate molecules of interest via green processes. This study is focused on the two step etherification of glycerol with alcohols over acid catalysts. The main prospect of this project is the study of the relationships between the structures of the mono-, di- and tri-ethers (MEG, DEG and TEG) and their properties for lubricant applications. The tribological properties of these products as friction modifiers have been evaluated at the TOTAL Research Center in Solaize. The formation of ethers of glycerol with alcohols has already been widely studied in the literature. To overpass the immiscibility between glycerol and fatty alcohols the first etherification has be performed with a short alcohol as a reactant, while the second has been performed with a fatty alcohol, the previously obtained mono-ethers being miscible with fatty alcohols. Thus, the formation of di- and tri-ethers of glycerol with more than twenty carbons becomes possible. In this work, the reaction parameters (ratio between reactants, the nature and amount of catalyst, and the purification) were optimized for two model reactions. The first reaction was the etherification between glycerol and 1-hexanol and the second was the etherification of the previously obtained MEG with 1-hexanol. One of the main challenges of these reactions is the separation and purification of the ethers, because of their very structures, and the presence of by-products such as oligomers of glycerol or ethers. The optimization of the purification process of the ethers has then been one of the major challenges of this work. The best purification conditions have allowed the extraction of 80% of the synthesized mono-hexyl ether from the reaction medium.The optimization of operating conditions of the various reactions used, as well as the purification of the obtained ethers, allowed the extension of the scope of reaction to several alcohols of different structures. Consequently, eighteen different samples of mono- and/or di-ethers of glycerol have been obtained and tested at the TOTAL Research Center in Solaize as friction modifiers in lubricants. These tests have led to the establishment of relationships between the chemical structure of the molecules and their tribological properties.

Anaerobic digestion can be used to sustainably treat the organic byproducts of the biodiesel process (crude glycerol and biodiesel wastewater) while generating a renewable natural gas to be used for heating or electricity generation. The purpose of this thesis was to (1) investigate the possibility of co-digestion of biodiesel byproducts without use of external substrates or pretreatment and (2) assess the impact of various acclimatization rates on the stability and efficiency of such a system. Two inocula (effluent from a wastewater treatment plant digester and from an agro-industrial waste digester) and two acclimatization rates were studied. The results showed that co-digestion of crude glycerol and biodiesel wastewater at high organic loading rates(up to 6.8 g COD L-1day-1)is possible without addition of other substrates or pretreatment.Thecumulative biogas production of the digesters using inoculum from the agro-industrial waste digester was statistically greater than the digesters using the wastewater treatment plant digester, indicating that similar inoculum could be useful for additional experiments.In addition,maximum efficiency due to a slower rate of acclimatization was higher for both inocula, up to a maximum average daily biogas yield of 621 mL biogas g-1COD added.Finally, comparison of two methods for measuring gas production (mass difference and volumetrically using a syringe) revealed a reasonable correlation(R2= 0.97)between the methods. Additional validation could lead to use of the mass difference method as a validation method or an alternative gas production measurement method.

The Brazilian sugarcane and ethanol industries produce lot of waste which has potential for energy production. Anaerobic digestion (AD) can be effectively utilized for producing biogas from these wastes. During the AD process, huge volumes of digestate are produced with some being employed in fertilizer application whilst large volumes are mostly stored in uncovered tanks. This result in emission of residual methane and loss of energy which can be recovered through post- digestion approaches. To analyse optimal utilization of this digestate and enhanced biogas production, co- digestion of post- digestate from a continuously stirred reactor (CSTR) performing co-digestion of sugarcane waste from Brazil (Vinasse, filter cake and straw) with addition of different glycerol concentrations were studied. The addition of glycerol characterised by its biodegradability and high organic content makes it a suitable substrate to enhance biogas production. A biomethane potential was assessed when the digestate was co-digested with 15% and 25% CODg/L of glycerol. The batch test lasted for 39 days. The results demonstrated that, co-digestion of digestate with glycerol has the potential of increasing cumulative methane and biogas yield with 25% addition producing the highest methane and biogas yield (318 Nml/gCOD and 196 Nml/gCOD) which was approximately 6 times higher compared to mono-digestion of the digestate. Anaerobic co-digestion of digestate and glycerol was examined in two lab scale reactors (CSTR) at mesophilic conditions (35oC) and were run for 90 days. The reactor (R1) performing co-digestion increased methane and biogas production by 300% and 170% when glycerol concentrations of 15% and 25% of influent COD were added, respectively. Moreover, there was a decrease in CH4 yield when the reactors were continuously fed with 15% and 25% CODg/L of glycerol. This was an indication that, microorganisms easily digested glycerol addition at the early stages. Glycerol addition (50% CODg/L) resulted in a decrease in CH4 and biogas production.  This result shows, CH4 yields in the post-digester can be enhanced with glycerol addition if it does not exceed a limiting of 50% of the organic loading rates of the feed.

[ES] La presente tesis doctoral se sitúa en el marco de la actual transición energética, que plantea la sustitución progresiva de materias primas de origen fósil por fuentes renovables, tanto para la obtención de productos químicos como para la producción de combustibles. En este contexto de transición paulatina a las renovables, y teniendo en cuenta los últimos pronósticos, las fuentes fósiles (fundamentalmente gas natural) y derivados de la biomasa, jugarán un papel fundamental durante el cambio. Se ha llevado a cabo un estudio sobre el empleo de óxidos metálicos (basados en bronces de wolframio o en óxido de níquel), como catalizadores para: i) la transformación de derivados de biomasa: de glicerol a acroleína/ácido acrílico; y de compuestos oxigenados de cadena corta presentes en efluentes acuosos (procedentes de tratamientos de extracción de bio-aceites de pirolisis) a combustibles; y ii) la transformación de componentes del gas natural, concretamente la obtención de etileno a partir de etano, mediante deshidrogenación oxidativa (ODH). El trabajo se presenta desde una perspectiva de la química de materiales, haciendo hincapié en las propiedades fisicoquímicas de los distintos sistemas catalíticos, empleando técnicas de caracterización convencionales e in situ, además de reacciones modelo (transformación de metanol y etanol), con el objetivo de entender las funciones catalíticas presentes en cada caso. Tanto para la transformación de glicerol en fase gas, como para la valorización de mezclas acuosas de compuestos oxigenados de cadena corta, se han utilizado catalizadores basados en bronces de wolframio. Se ha tratado de poner de manifiesto la gran versatilidad composicional y estructural (con el consiguiente control de las propiedades funcionales), que presentan este tipo de materiales. En este sentido, las propiedades ácidas y redox de catalizadores W-V-O pueden ser moduladas, para una misma concentración de vanadio, mediante el control de la relación de fases cristalinas (hexagonal y monoclínica) del óxido de wolframio. Este efecto se ha estudiado empleando la transformación aeróbica de metanol como reacción "test", y tiene una gran influencia en la deshidratación oxidativa de glicerol a ácido acrílico. A su vez, mediante la sustitución isomórfica de wolframio por niobio (en el sistema WO3-Nb2O5) es posible controlar la relación de centros ácidos de tipo Brönsted y Lewis en la superficie de los materiales. Por un lado, los catalizadores con una alta relación Brönsted/Lewis se han mostrado más efectivos en la deshidratación de glicerol a acroleína, mientras que los catalizadores con altas concentraciones de centros de tipo Lewis presentan altos rendimientos a productos de condensación de compuestos oxigenados de cadena corta. Adicionalmente se han estudiado las diferencias entre catalizadores (bien óxidos mixtos W-V-O o W-Nb-O) preparados mediante un método hidrotermal o mediante reflujo, así como el efecto de la utilización de un soporte mesoporoso (KIT-6), sobre sus propiedades catalíticas en la transformación aeróbica en fase gaseosa de etanol y glicerol. Finalmente, en lo que concierne a la transformación de componentes del gas natural, se han empleado materiales basados en óxido de níquel (soportado sobre distintos óxidos y/o promovido con distintos metales) como catalizadores para la ODH de etano. En este caso el estudio se ha centrado fundamentalmente en dilucidar los efectos de promotores y soportes en la naturaleza y propiedades fisicoquímicas del óxido de níquel, los cuales dan lugar a un cambio drástico en sus propiedades catalíticas. Así, se ha observado que modificando la reducibilidad y las características superficiales del óxido de níquel es posible transformar un catalizador muy poco selectivo en la ODH de etano (como es el NiO, con una selectividad a etileno del 30 %) en uno de los catalizadores más selectivos para llevar a cab / [CA] Aquesta tesi doctoral es situa dins del marc de l'actual transició energètica, la qual planteja la substitució progressiva de les primeres matèries d'origen fòssil per fonts renovables, tant per a l'obtenció de productes químics com per a la producció de combustibles. En aquest context de transició gradual a les renovables, i tenint en compte els últims pronòstics, les fonts fòssils (principalment el gas natural) i els derivats de la biomassa, exerciran un paper fonamental durant aquest canvi. S'ha dut a terme un estudi sobre la utilització d'òxids metàl·lics (basats en bronzes de wolframi o en òxid de níquel), com a catalitzadors per a: i) la transformació de derivats de la biomassa: de glicerol a acroleïna/àcid acrílic; i de compostos oxigenats de cadena curta presents en efluents aquosos (procedents de tractaments d'extracció de bio-olis de la piròlisi) a combustibles; i ii) la transformació de components del gas natural, concretament l'obtenció d'etilè a partir d'età, mitjançant la deshidrogenació oxidativa. El treball es presenta des del punt de vista de la química de materials, posant l'accent en les propietats fisicoquímiques dels diferents sistemes catalítics, utilitzant tècniques de caracterització convencionals i in situ, a més de reaccions model, amb l'objectiu d'entendre les funcions catalítiques presents en cadascun dels casos. Tant per a la transformació del glicerol en fase gasosa com per a la valorització de les mescles aquoses de compostos oxigenats de cadena curta, s'han utilitzat catalitzadors basats en bronze de wolframi. S'ha intentat posar de manifest la gran versatilitat de composicions i estructures (amb el conseqüent control de les propietats funcionals) que presenten aquest tipus de materials. En aquest sentit, les propietats àcides i redox dels catalitzadors de W - V - O poden ser modulades, per a una mateixa concentració de vanadi, mitjançant el control de la relació de fases cristal·lines (hexagonal i monoclínica) de l'òxid de wolframi. Aquest efecte s'ha estudiat utilitzant la transformació aeròbica de metanol com a reacció "test", i presenta una gran influència en la deshidratació oxidativa de glicerol a àcid acrílic. Al mateix temps, mitjançant la substitució isomòrfica de wolframi per niobi (en el sistema WO3 - Nb2O5), és possible controlar la relació de centres àcids de tipus Brönsted i Lewis en la superfície dels materials. Per una part, els catalitzadors que presenten una relació Brönsted / Lewis alta s'han mostrat més efectius en la deshidratació de glicerol a acroleïna, mentre que els catalitzadors amb unes altes concentracions de tipus Lewis presenten alts rendiments a productes de condensació de compostos oxigenats de cadena curta. Addicionalment, s'han estudiat les diferències entre catalitzadors (ja siguin òxids mixtos W-V-O o W-Nb-O) preparats mitjançant un mètode hidrotermal o mitjançant un mètode de reflux, així com l'efecte que presenta la utilització d'un suport mesoporós (KIT-6), sobre les seves propietats catalítiques en la reacció de transformació aeròbica en fase gasosa d'etanol i glicerol. Finalment, pel que fa referència a la transformació de components del gas natural, s'han utilitzat materials basats en òxid de níquel (suportat sobre diferents òxids i/o promoguts amb diferents metalls) i catalitzadors per a la deshidrogenació oxidativa d'età. En aquest cas, l'estudi s'ha focalitzat principalment en dilucidar els efectes de promotors i suports en la naturalesa i propietats fisicoquímiques de l'òxid de níquel, els quals impliquen un canvi dràstic en les seves propietats catalítiques. Així doncs, s'ha observat que modificant la reductibilitat i les característiques superficials de l'òxid de níquel és possible transformar un catalitzador molt poc selectiu en la deshidrogenació oxidativa de l'età (com és el cas del NiO, amb una selectivitat a l'etilè del 30%) en un dels cata / [EN] The present doctoral thesis is set within the scope of the current energy transition, which considers the progressive substitution of non-renewable fossil sources by renewable feedstocks for the production of chemicals and fuels. In this context of gradual transition, and according to recent energy outlooks, fossil sources (especially natural gas) and biomass feedstocks will play a key role during the shift. A study on the use of metal oxides (based on tungsten bronzes or nickel oxides) as catalysts for different reactions has been conducted. Particularly, they have been studied as catalytic materials for: i) the transformation of biomass-derived feedstocks: glycerol transformation into acrolein/acrylic acid, and the transformation of short-chain oxygenates present in aqueous effluents (derived from extraction processes of pyrolysis bio-oils) into fuels; and ii) the valorization of natural gas components, i.e. the transformation of ethane into ethylene by oxidative dehydrogenation. The work is presented from a materials chemistry perspective, emphasizing the physicochemical characteristics of the different catalytic systems by using conventional and in situ characterization techniques and model reactions (gas phase methanol and ethanol transformation); with the aim of understanding the specific catalytic functionalities present in each case. For both gas phase glycerol transformation and the valorization of short-chain oxygenates aqueous mixtures, catalyst based on tungsten oxide bronzes have been used. The compositional and structural versatility of this structural types (with the subsequent control of their functional properties) will be highlighted. In this sense, the acid-redox properties of W-V-O catalysts can be modulated by controlling the crystalline phase composition in the materials (i.e. hexagonal and monoclinic polymorphs of tungsten oxide) at a fixed V concentration. This effect has been studied by using the gas-phase aerobic transformation of methanol as a surface test reaction. The concentration of the hexagonal and monoclinic polymorphs in the catalysts has also an important influence in the gas-phase transformation of glycerol into acrylic acid. Also, it is possible to control the Brönsted/Lewis acid nature of the surface by the isomorphic substitution of Nb for W in WO3-Nb2O5 system. On the one hand, catalysts showing a higher proportion of Brönsted acid sites are more effective in the glycerol dehydration to acrolein. On the other hand, materials with a higher concentration of Lewis acid sites display high yields to condensation products in the aqueous phase valorization of short chain oxygenates. Additionally, the differences between W-V-O and W-Nb-O catalysts prepared by both reflux and hydrothermal methods have been studied. Also the effect of adding a mesoporous KIT-6 silica as support on the catalytic performance in the gas phase transformation of ethanol and glycerol will be underlined. Considering the transformation of natural gas components, nickel oxide-based materials were chosen (either supported on different oxides and/or promoted with different metals) to perform the oxidative dehydrogenation (ODH) of ethane. In this case the study has been focused on elucidating the effects of both promoters and supports on the nature and physicochemical features of nickel oxide, which lead to a drastic change in the catalytic behavior of these materials. This way, it has been observed that by the modification of the reducibility and the chemical nature of nickel oxide, it is possible to transform an apparently non-selective catalyst in the ODH of ethane (like NiO, showing a selectivity to ethylene of ca. 30 %) into one of the most selective catalysts reported in the literature (presenting a selectivity to ethylene of ca. 90 %). / También me gustaría agradecerle al Prof. Avelino Corma, investigador principal del proyecto SEV-2012-0267, a través del cual he podido realizar mi tesis doctoral enel Instituto de Tecnología Química (SVP-2014-068669). / Delgado Muñoz, D. (2019). Catalytic valorization of natural gas and biomass-derived feedstocks by metal oxides [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/122298 / TESIS