Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2017-04-04T17:44:44Z No. of bitstreams: 2 Dissertação - Dayane Cristina da Costa - 2015.pdf: 3605790 bytes, checksum: 658bb1dcde761f2620d842c1efb18c40 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-04-05T10:49:23Z (GMT) No. of bitstreams: 2 Dissertação - Dayane Cristina da Costa - 2015.pdf: 3605790 bytes, checksum: 658bb1dcde761f2620d842c1efb18c40 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-04-05T10:49:23Z (GMT). No. of bitstreams: 2 Dissertação - Dayane Cristina da Costa - 2015.pdf: 3605790 bytes, checksum: 658bb1dcde761f2620d842c1efb18c40 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-08-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The need to study new sources of raw materials grease for biodiesel production has led the search for potential new lipid sources such as microalgae. There are several evaluation strategies of microalgae potential for biodiesel production, but none of them correlates the potential of microalgae relative to the oil already consolidated as raw materials greases. Moreover, it is important to know the composition of fatty acids in microalgae as they determine the quality of the produced biodiesel. In Brazil there are no standards governing the quality of biodiesel produced by this raw material, however, according to EN 14214, the limit for linolenic acid content (Ln) is up 12 %, and polyunsaturated fatty acids more than 4 double bonds (PUFA) is up to 1 %. Thus, this work presents the determination of the lipid content of microalgae compared to soybean oil, for standardization, measurement and gravimetry curve, beyond the fatty acid composition of 90 freshwater and marine microalgae, analyzed by gas chromatography. Microalgae Scenedesmus acuminatus and Westella botryoides showed the highest yields esters by quantifying curve, and the microalgae Scenedesmus acuminatus stands out for presenting suiting FAME profile for biodiesel production. Among the species analyzed gravimetrically stands out microalgae Hariotina reticulata and Phytoplankton grown on 16/04/12, with yields above 460 mg / g biomass heavy. The determination for normalization revealed Chlorella minutissima species Coelastrum sp., Scenedesmus bijugus, Kirchneriella irregulares and Selenastrum bibraianum as promising sources of lipids, with incomes above 200 %. Regarding the fatty acid composition of these microalgae Chlorella minutissima only the species and Coelastrum sp. presented profile of fatty acids that are similar to those found in oil consolidated in biodiesel production and should thus provide the production of biodiesel that meets the market's quality requirements. / A necessidade de se estudar novas fontes de matérias-primas graxas para produção de biodiesel tem levado a busca por novas potenciais fontes lipídicas, tais como as microalgas. Existem várias estratégias de avaliação do potencial de microalgas para a produção de biodiesel, mas nenhuma delas correlaciona o potencial das microalgas relativamente ao de oleaginosas já consolidadas como matérias-primas graxas. Além disso, é importante conhecer a composição de ácidos graxos nas microalgas já que estes determinam a qualidade do biodiesel produzido. No Brasil não existem padrões que regem a qualidade do biodiesel produzido por essa matéria prima, porém, segundo a norma EN 14214, o limite para o teor de ácido linolênico (Ln) é de até 12 %, e de ácidos graxos poli-insaturados com mais de 4 duplas ligações (PUFA) é de até 1 %. Desta forma, este trabalho apresenta a determinação do conteúdo lipídico das microalgas em relação ao óleo de soja, por normalização, curva de quantificação e gravimetria, além da composição de ácidos graxos de 90 microalgas dulcícolas e marinhas, analisadas por cromatografia gasosa. As microalgas Scenedesmus acuminatus e Westella botryoides apresentaram os maiores rendimentos em ésteres pela curva de quantificação, sendo que a microalga Scenedesmus acuminatus se destaca por apresentar adequando perfil de FAME para produção de biodiesel. Dentre as espécies analisadas por gravimetria destaca-se as microalgas Hariotina reticulata e o Fitoplâncton cultivado em 16/04/12, com rendimentos acima de 460 mg/ g de biomassa pesada. A determinação por normalização revelou as espécies Chlorella minutíssima, Coelastrum sp., Scenedesmus bijugus, Kirchneriella irregulares e Selenastrum bibraianum como promissoras fontes de lipídeos, com rendimentos acima de 200 %. Com relação a composição de ácidos graxos dessas microalgas somente as espécies Chlorella minutíssima e Coelastrum sp. apresentaram perfil de ácidos graxos que são similares aos encontrados em oleaginosas consolidadas na produção de biodiesel, devendo assim proporcionar a produção de biodiesel que atenda as exigências de qualidade do mercado.

Made available in DSpace on 2016-08-19T12:56:44Z (GMT). No. of bitstreams: 1 Dissertacao Inocencio.pdf: 2764893 bytes, checksum: 8b5e78c33e9a9309d46a3f7ff7b3a5e9 (MD5) Previous issue date: 2013-04-03 / FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTIFICO E TECNOLÓGICO DO MARANHÃO / Biodiesel is obtained mainly by homogeneous catalysis, however this process has disadvantages as saponification of the esters and difficulty of separation of the catalyst from the products formed. In this work, ceramic catalysts were prepared from the surface modification of niobia with alkaline earth metals (Ba and Ca) and transition metals (Ni and Cu) in order to improve the catalytic activity in the transesterification reaction of beef tallow and esterification of oleic acid. The catalysts were obtained by the polymeric precursor method (PPM). Therefore, such systems were characterized by X-ray diffraction (XRD) and infrared spectroscopy in the Fourier transform (FTIR), Raman spectroscopy and transmission electron microscopy (TEM) analysis of gas adsorption. The XRD results suggest that the niobium surface modification, but with secondary phases. Raman spectra of the catalysts exhibit vibrational modes near 701 cmˉ¹ corresponding to phase T-Nb₂O₅. The bands between 311 cmˉ¹ and 230 cmˉ¹, corresponding to vibrational modes of the bonds O-Nb-O, Nb-O-Nb. FTIR spectra showed vibrational modes in the region between 500 - 850 cmˉ¹ which may be associated with a NbO₆ octahedra, vibrations in modes 635 cmˉ¹, 560 cmˉ¹ and 500 cmˉ¹ are associated Nb-O bonds in Nb-O6 octahedra distorted. A cursory analysis shows that the catalysts are non-porous materials. The catalysts of niobium modified barium and copper, calcium and copper, barium and calcium, and nickel and nickel exhibited catalytic activity for transesterification of beef tallow and oleic acid esterification. The catalysts modified with 5% barium and copper, showed better conversion to oleic acid esterification and transesterification beef with 71% to 95%, respectively. Thus, these catalysts were effective for the transesterification of beef tallow and oleic acid esterification. / O biodiesel é obtido principalmente via catálise homogênea, entretanto esse processo apresenta desvantagens como saponificação dos ésteres e a dificuldade de separação do catalisador dos produtos formados. Neste trabalho, foram preparados catalisadores cerâmicos a partir da modificação da superfície da nióbia, com metais alcalinos terrosos (Ba e Ca) e metais de transição (Ni e Cu), no intuito de melhorar a atividade catalítica desses materiais na reação de transesterificação do sebo bovino e esterificação do ácido oléico. Os catalisadores foram obtidos pelo método dos precursores poliméricos (MPP). Para tanto, tais sistemas foram caracterizados por difração de raios X (DRX), espectroscopia na região do infravermelho com transformada de Fourier (FTIR), espectroscopia Raman, Microscopia eletrônica de transmissão (TEM) e Análise de adsorção de gás. Os resultados de DRX sugerem a modificação da superfície do nióbio, porém com fases secundárias. Os espectros Raman dos catalisadores exibem modos vibracionais próximos a 701 cmˉ¹ corresponde à fase T-Nb₂O₅. As faixas compreendidas entre 311 cmˉ¹ e 230 cmˉ¹, correspondem aos modos vibracionais das ligações O-Nb-O, Nb-O-Nb. Os espectros FTIR apresentaram modos vibracionais na região entre 500 - 850 cmˉ¹ que pode se associado aos octaedros de NbO6, os modos vibrações em 635 cmˉ¹, 560 cmˉ¹ e 500 cmˉ¹ são associadas as ligações Nb-O em octaedros Nb-O₆ distorcidos. A análise superficial demonstrou que os catalisadores são materiais não porosos. Os catalisadores de nióbio modificados com bário e cobre, cálcio e cobre, bário e níquel e cálcio e níquel apresentaram atividade catalítica para transesterificação de sebo bovino e esterificação do ácido oléico. Os catalisadores modificados com o bário 5% e cobre, apresentaram melhor conversão para esterificação do ácido oléico e transesterificação do sebo bovino com 71% e 95%, respectivamente. Desta forma, esses catalisadores mostraram-se eficientes para reação de transesterificação do sebo bovino e esterificação do ácido oléico.

Orientador: Neura Bragagnolo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-22T21:30:57Z (GMT). No. of bitstreams: 1 Medina_AlineLisboa_D.pdf: 1555099 bytes, checksum: 5e3406d24ad9cc9e5db186ae2c4b697b (MD5) Previous issue date: 2013 / Resumo: O uso da energia de micro-ondas tem sido explorado para extração de compostos e para aceleração de reações químicas em diferentes amostras. Os métodos convencionais utilizados para extração de lipídios possuem limitações, como longo tempo, grande volume de solventes, e ainda a possibilidade de degradação dos compostos de interesse. Neste estudo foram desenvolvidos, com o uso de delineamento composto central rotacional, novos métodos de extração de lipídios e de transesterificação de triacilgliceróis em carnes, assistidos por micro-ondas. As condições utilizadas no procedimento para extração de lipídios foram: 300 mg de amostra, 54 °C e 15 minutos. O método de extração de lipídios em carnes assistido por micro-ondas resultou na obtenção de teores de lipídios sem diferença estatística do método de Folch. Além disso, não foi observada alteração na composição de ácidos graxos e formação de produtos de oxidação lipídica durante a extração, o que permite o uso do método sem a possibilidade de alteração química dos compostos. Para a transesterificação dos triacilgliceróis foram desenvolvidos dois métodos, sendo que no primeiro, a transesterificação é realizada no lipídio previamente extraído e no segundo método, a transesterificação é realizada diretamente nas amostras de carne. Em ambos os métodos foi excluído o uso de trifluoreto de boro, utilizado em metodologias convencionais como catalizador da reação. Nesse estudo, o hidróxido de sódio em metanol a 0,5 % foi utilizado como catalizador, sendo a reação acelerada pela energia de micro-ondas. Para a transesterificação dos triacilgliceróis da amostra de lipídios foram necessários 5 minutos de irradiação a 60 °C enquanto que na transesterificação direta de triacilgliceróis da amostra de carne, 30 minutos a 60 °C porém, no último caso, não é necessária a etapa da extração dos lipídios. Com o uso da energia de micro-ondas foi possível desenvolver métodos precisos e exatos para a extração de lipídios e obtenção de ésteres metílicos de ácidos graxos em carne / Abstract: Microwave energy has been used for compound extractions and for accelerating chemical reactions in different samples. The conventional methods used for lipid extraction has limitations like long time required, large solvent volume, and the possibility of compound degradation. In this study were developed, with response surface method, new methods for microwave-assisted lipid extraction and microwave-assisted triacylglycerols transesterification from meat. The parameters used in this procedure were: 300 mg of sample, 54 °C and 15 minutes. The microwave-assisted lipid extraction method resulted in lipid content with no difference when compared to the Folch method. Furthermore, no oxidation products were observed during the extraction, enabling the use of this method with no chance of chemical alteration of the compounds. For the triacylglycerols transesterification were developed two methods, being the first one a lipid transesterification with a lipid previously extracted, and a second method that allows a direct sample transesterification. In both methods it was excluded the use of boron trifluoride, originally used in conventional methods as a reaction catalyst. In this study, methanol sodium hidroxide (0,5 %) was used as catalyst, with the reaction being accelerated by the microwave energy. For lipid transesterification it was necessary 5 minutes of irradiation at 60 °C, and for direct transesterification, 30 minutes at 60 °C, however, in the latter case, it is not necessary the lipid extraction step to obtain the fatty acids methyl esters. It can be concluded that the use of microwave energy provides accurate and precise methods, faster, with less solvent volumes and sample mass when compared to conventional methods / Doutorado / Ciência de Alimentos / Doutora em Ciência de Alimentos

Orientadores: Telma Teixeira Franco, Gustavo Paim Valença / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-23T22:38:12Z (GMT). No. of bitstreams: 1 Reis_ErikaMarques_M.pdf: 5864399 bytes, checksum: 2029f038d594a8b5a6f1c34fc59a68f5 (MD5) Previous issue date: 2013 / Resumo: A procura por combustíveis renováveis tem aumentado e o óleo vegetal transesterificado (biodiesel) surge como alternativa mais promissora em relação ao petróleo e seus derivados, superando problemas de matrizes energéticas e ambientais. A obtenção do biodiesel é de interesse estratégico, por sua viabilidade econômica e a fácil adaptação no mercado de combustíveis. As principais matérias-primas do biodiesel são espécies vegetais oleaginosas com diferentes níveis de produtividade e adaptação a cada região do Brasil. Além das plantas oleaginosas, leveduras, fungos e microalgas são capazes de acumular lipídios, desempenhando papel fundamental na substituição de biodiesel oriundo de vegetais. A Agência Nacional de Petróleo (ANP) permitiu a incorporação de 10% de biodiesel ao diesel promovendo grande aumento na demanda de biodiesel. O presente trabalho tem como proposta investigar a transesterificação convencional e in situ da levedura Lipomyces starkeyi por rota etílica na presença de catalisadores (NaOH e H2SO4 ) para obtenção de biodiesel. No presente estudo a concentração mássica de lipídios de L. starkeyi pelo método Bligh & Dyer (51,15% ± 1,48) e o efeito do solvente sobre a extração lipídica por Soxhlet de L. starkeyi (hexano 2,36%, clorofórmio: metanol (44,75%) e etanol (32,76%) e Butt (hexano 26,18%, clorofórmio: metanol (40,81%) e etanol (30,19%) foram estudados. A eficiência da extração está relacionada diretamente com a polaridade do solvente. A composição do óleo foi determinada pela esterificação a ésteres metílicos e analisados por cromatografia gasosa. O óleo de L. starkeyi é composto basicamente por seis ácidos graxos entre 14 e 18 carbonos, com baixo grau de insaturação, característica desejável para a produção de biodiesel. A caracterização do óleo foi determinada por métodos teóricos e experimentais. A determinação de acilgliceróis por cromatografia líquida de alta perfomance por exclusão de tamanho do óleo observou-se que o hexano e clorofórmio: metanol obtiveram maior concentração de triacilglicerídios que o etanol. As transesterificaçoes in situ catálise ácida foi analisada por cromatografia gasosa acoplada a espectrômetro de massas. / Abstract: The demand for renewable fuels has increased and transesterified vegetable oil (biodiesel) emerges as a promising alternative to oil and its derivatives, overcoming problems of energy and environmental matrices. Obtaining biodiesel is of strategic interest for its economic viability and the easy adaptation of the fuel market. The main raw materials of vegetable oil biodiesel are species with different levels of productivity and adaptation to each region of Brazil. In addition to the oil plants, yeasts, microalgae and fungi are able to accumulate lipids, playing a key role in the replacement of biodiesel derived from vegetable. The National Petroleum Agency ( ANP ) has allowed the incorporation of 10 % biodiesel to diesel promoting large increase in demand for biodiesel . This paper aims to investigate the transesterification in situ and conventional yeast Lipomyces starkeyi by ethyl route in the presence of catalysts ( NaOH and H2SO4) to obtain biodiesel . In this study the mass concentration of lipids of L. starkeyi method by Bligh & Dyer ( 51.15% ± 1.48 ) and the effect of solvent on the extraction of lipids by Soxhlet ( 2.36% hexane , chloroform : methanol ( 44.75% ) and ethanol ( 32.76 %) and Butt ( 26.18% hexane , chloroform : methanol ( 40.81 %) and ethanol ( 30,19 % ) were studied the extraction efficiency is directly related to the polarity of the solvent . The oil composition was determined by esterification to methyl esters and analyzed by gas chromatography. The oil L. Starkeyi is basically composed of six fatty acids between 14 and 18 carbons, with a low degree of unsaturation, a desirable characteristic for the production of biodiesel . The characterization of the oil was determined by theoretical and experimental methods. The determination of glycerides by liquid chromatography high performance size exclusion of the oil showed that the hexane and chloroform: methanol showed higher concentration of triacylglycerols that ethanol. The transesterifications in situ acid catalysis was analyzed by gas chromatography- mass spectrometry. / Mestrado / Engenharia de Processos / Mestra em Engenharia Química

Orientador: Maria Regina Wolf Maciel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T03:53:54Z (GMT). No. of bitstreams: 1 Dantas_TarcisioSoaresSiqueira_M.pdf: 911186 bytes, checksum: 5dd1da3ddee6346c9e4cbb05214e5f7d (MD5) Previous issue date: 2011 / Resumo: A transesterificação com etanol é um tópico de pesquisa bastante atual devido à possibilidade de produzir um combustível utilizando apenas fontes renováveis. Este trabalho apresenta a produção de biodiesel em uma coluna de destilação reativa de pratos perfurados e a otimização de suas variáveis de processo foi realizada utilizando ferramentas estatísticas. A destilação reativa é a implementação simultânea de reação e separação em uma mesma unidade de processo e, através dela, é possível atingir conversões altas rapidamente e com menores gastos energéticos. O óleo de soja e o óleo de milho refinados foram utilizados como matérias-primas na reação de transesterificação com o etanol e o catalisador (hidróxido de sódio). Os resultados finais de conversão em éster foram comparados com resultados obtidos por outros pesquisadores em uma coluna de destilação reativa empacotada. A conversão ótima de éster foi de 99,84% em peso com 6 minutos de reação e um modelo, com significância estatística, da conversão em éster em função da razão molar álcool:óleo e da concentração de catalisador foi obtido / Abstract: Transesterification with ethanol is very up-to-date due to the possibility of producing a fuel solely from renewable sources. This work presents the biodiesel production with a reactive distillation sieve tray column and the optimization of the process variables using statistical tools was carried out. Reactive distillation is the simultaneous implementation of reaction and separation within a single process unit and it is able to achieve very fast conversions and high yields with relatively low energy requirements. Refined soybean oil and corn oil where used as feedstocks in the transesterification with the ethanol and the sodium hydroxide catalyst. The results on the final ester conversion where compared to results obtained with a packed reactive distillation column by other researchers. The optimum ester (biodiesel) conversion was 99.84 wt. % after 6 minutes of reaction and a model, with statistical significance, of the ester conversion as a function of molar ratio and catalyst concentration was obtained / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientadores: Martin Aznar, Sérgio Duvoisin Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-21T20:26:45Z (GMT). No. of bitstreams: 1 Rocha_EnioGomesdeAzevedo_M.pdf: 2064033 bytes, checksum: f91a84bce4c2b9d8bb4142c612dffb37 (MD5) Previous issue date: 2012 / Resumo: O biodiesel é uma fonte de energia renovável promissora e é do interesse das matrizes energéticas brasileiras e mundiais em razão da futura escassez de combustíveis fósseis, e das considerações ambientais sobre a diminuição das emissões poluentes. Este trabalho objetiva a produção de biodiesel etílico a partir de óleo de palma da região amazônica, e a determinação experimental e modelagem termodinâmica de dados de equilíbrio líquido-líquido em sistemas ternários compostos por biodiesel de óleo de palma + etanol + glicerina e biodiesel de óleo de palma + etanol + água, nas temperaturas de 25 °C e 50 ºC, à pressão atmosférica. As técnicas analíticas para determinação das composições das fases incluíram densimetria e índice de refração. Os dados de equilíbrio experimentais foram correlacionados com o modelo NRTL para o coeficiente de atividade e o modelo foi capaz de representar corretamente o comportamento destes dados, fornecendo uma boa descrição dos diagramas de fase dos sistemas estudados / Abstract: Biodiesel is a renewable energy source and is awakening the interest of Brazilian and global energy matrix because of future shortages of fossil fuels and environmental concerns about the reduction of pollutant emissions. This work aims at the production of ethyl biodiesel from palm oil of the Amazon region, and the experimental determination and thermodynamic modeling data of liquid-liquid equilibrium in ternary systems composed by palm oil biodiesel + ethanol + glycerol and palm oil biodiesel + ethanol + water at temperatures of 25 °C and 50 °C, at atmospheric pressure. The analytical techniques for determining the compositions of the phases included densimetry and refractive index. The experimental equilibrium data were correlated with the NRTL model for the activity coefficient. The model was able to correctly represent the behavior of the experimental data, providing a good description of the phase diagrams of the studied systems / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientadores: Maria Isabel Rodrigues, Gabriela Alves Macedo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-20T23:36:07Z (GMT). No. of bitstreams: 1 Maldonado_RafaelResende_D.pdf: 966845 bytes, checksum: ddc61b8ed34d47c4c2ebff5a3967c4a7 (MD5) Previous issue date: 2012 / Resumo: A crescente necessidade por energia e o avanço das preocupações com problemas ambientais devido ao uso de combustíveis fósseis tem levado a busca de alternativas para a área energética. Dentro deste contexto, a produção de biocombustíveis como etanol e biodiesel mostram um grande potencial de avanço e despertam amplo interesse na área de pesquisas.O biodiesel é comumente obtido por reações de transesterificação com catálise alcalina, no entanto a via enzimática constitui-se em uma forma promissora para a produção deste tipo de combustível. Este trabalho analisou as etapas de produção, purificação e imobilização da lipase de Geotrichum candidum NRRLY-552 e aplicação dessa enzima na biocatálise das reações de hidrólise, esterificação e transesterificação de óleos vegetais em diferentes sistemas reacionais. Os resultados obtidos demonstraram que a lipase de Geotrichum candidum NRRLY-552 pode ser obtida a baixo custo, com a utilização de um resíduo agro-industrial (água de maceração de milho) com atividade lipolítica de cerca de 20 U/mL. A purificação parcial desta enzima foi realizada por dois métodos ¿ precipitação com sulfato de amônio e precipitação com etanol, seguido de liofilização em ambos os casos. Tais métodos proporcionaram a obtenção de um preparado enzimático com atividade lipolítica de cerca de 500 U/g em duas ou três etapas. O pequeno número de etapas e a elevada atividade enzimática propiciam a aplicação desta enzima para biocatálise de reações com óleos vegetais para uso na produção de biocombustíveis. A enzima selecionada apresentou um bom desempenho para a reação de hidrólise de óleos vegetais, atingindo taxas de hidrólise de cerca de 80% após 24 horas de reação, em frascos agitados a 210 rpm, 45oC e 15% m/m de água no meio reacional com uma concentração de enzima de 5% m/m da lipase. A enzima não apresentou ação de esterificação suficiente para produção de biodiesel na presença de etanol, no entanto o sistema reacional desenvolvido permite que a associação com outras lipases de boa ação de esterificação possibilite a obtenção do biodiesel a partir do hidrolisado obtido neste trabalho / Abstract: The growing energy necessity and the advancement of environmental concerns due to the use of fossil fuels have led the search for alternatives to the energy area. In this context, the production of biofuels like ethanol and biodiesel shows a great potential for advancement and arouse widespread interest in the area of research. Biodiesel is commonly obtained by transesterification with alkaline catalysis; however, the enzymatic pathway is a promising way to produce this type of fuel. This work studied the stages of production, purification and immobilization of lipase from Geotrichum candidum NRRLY-552 and application of this enzyme in the biocatalysis of the hydrolysis, esterification and transesterification of vegetable oils in different reaction systems. The results showed that the lipase from Geotrichum candidum NRRLY-552 can be obtained at a low cost, using a residue of the agro-industrial (corn steep liquor), with lipolytic activity of about 20 U/mL. Partial purification of this enzyme was performed by two methods - precipitation with ammonium sulphate and precipitation with ethanol, followed by lyophilization in both cases. Such methods provided to obtain an enzyme preparation with lipolytic activity of 500 U/g in two or three steps. The small number of steps and the high enzyme activity provide the application of this enzyme to catalysis of reactions with vegetable oils for the use in biofuel production. The selected enzyme showed a good performance for the hydrolysis of vegetable oils, reaching rates of hydrolysis of about 80% after 24 hours of reaction, in shaken flasks at 210 rpm, 45°C and 15% w/w of water in the reaction with enzyme concentration of 5% w/w of the lipase. The enzyme did not show enough action esterification for biodiesel production in presence of ethanol; however, the reaction system developed permits the association with other lipases with good deed esterification with allows obtainable biodiesel from the hydrolysed produced in this work / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

Dans le domaine de la valorisation des dérivés de la biomasse, les réactions de transestérification suscitent un grand intérêt en raison de leur importance pour transformer des molécules plateformes biobasées. L'étude des paramètres clés régissant une réaction de transestérification modèle, catalysée par des solides de type silicate de magnésium, a été menée. L'ensemble des données expérimentales (XRD, XPS, DRIFTS, RMN) a démontré qu'une phase de silicate de magnésium hydraté (MSH) est présente à la surface des catalyseurs les plus actifs. Cette phase, possédant une structure proche de celle d'une argile mais avec des défauts et présentant des propriétés acido-basiques spécifiques, est capable d'activer à la fois l'alcool (sur des sites basiques) et l'ester (sur des sites acides). Ce résultat est confirmé par l'étude cinétique qui met en évidence un mécanisme Langmuir-Hinshelwood. En outre, il a été montré que l'eau coordonnée au magnésium situé sur le bord des feuillets des particules ou dans les défauts présents à la surface des silicates engendre des sites acides particuliers.Par ailleurs, une série de phyllosilicates de magnésium, a été testée dans la réaction de transestérification modèle. Le rôle de la taille des particules a été mis en évidence et les meilleurs résultats catalytiques ont été obtenus avec le talc et la laponite possédant des tailles de feuillet nanométriques. De plus, l'étude cinétique indique que la réaction de transestérification catalysée par la laponite, n’ayant seulement que des sites basiques, implique un mécanisme Eley-Rideal. Enfin, dans le cas de la laponite la dissociation de l’eau sur les sites basiques empoissonne la réaction. / In the field of biomass derivatives valorisation, transesterification reactions have attracted numerous interest due to its importance to transform platform molecules. A study of the parameters governing the reactivity of magnesium silicate based catalyst in a model transesterification reaction was thoroughly undertaken. The set of experimental data (XRD, XPS, DRIFTS, NMR) demonstrated that a magnesium silicate hydrate (MSH) phase is formed at the surface of the most active silicates. It is thus concluded that this active phase, presented a clay-like structure with defects and specific acido-basic properties, is able to activate together the alcohol (over base sites) and the ester (over acid sites). This result fits with the kinetic study that implies the Langmuir-Hinshelwood mechanism. Moreover, the acid sites were revealed that are created from the water coordinated to magnesium located on the edge of the clay-like particles or in the defects present in the silicate layer.Besides, a series of phyllosilicates having the similar structure with MSH, were tested in the model transesterification reaction. The influence of the particles size was investigated and the best catalytic performances were obtained with talc and laponite with nanosheets. In addition, kinetic study indicates that the transesterification reaction on the laponite, with purely basic sites, undergoes Eley-Rideal mechanism. Finally, unlike the positive role of water on the formation of acid sites in MSH, on laponite, the dissociation of the water on basic sites poisons the reaction.

Philosophiae Doctor - PhD / The production of biodiesel (methyl esters) from vegetable oils represents analternative means of producing liquid fuels from biomass, and one which is growing rapidly in commercial importance and relevance due to increase in petroleum prices and the environmental advantages the process offers. Commercially, biodiesel is produced from vegetable oils, as well as from waste cooking oils and animal fats. These oils are typically composed of C14-C20 fatty acid triglycerides. In order to produce a fuel that is suitable for use in diesel engines, these triglycerides are usually converted into the respective mono alkyl esters by base-catalyzed transesterification with short chain alcohol, usually methanol. In the first part of this study, the transesterification reactions of three different vegetable oils; sunflower (SFO), soybean (SBO) and waste cooking oil (WCO) with methanol was studied using potassium hydroxide as catalyst in a conventional batch process. The production of biodiesel from waste cooking oil was also studied via continuous operation systems (employing the use of low frequency ultrasonic technology and the jet loop reactor). The characterisation of the feedstock used and the methyl ester products were determined by different analytical techniques such as gas chromatography (GC), high performance liquid chromatography (HPLC) and thin layer chromatography (TLC). The effects of different reaction parameters (catalyst amount, methanol to oil ratio, reaction temperature, reaction time) on methyl ester/FAME yield were studied and the optimum reaction conditions of the different process systems were determined. The optimum reaction conditions for production of methyl esters via the batch process with the fresh oil samples (SFO and SBO) were established as follows: a reaction time of 60 min at 60 ºC with a methanol: oil ratio of 6:1 and 1.0 KOH % wt/wt of oil; while the optimum reaction conditions for the used oil (WCO) was observed at a reaction time of 90 min at 60 ºC, methanol: oil ratio of 6:1 and 1.5% KOH wt/wt of oil. The optimum reaction conditions for the transesterification of the WCO via ultrasound technology applied in a continuous system in this study were: a reaction time of 30 min, 30 ºC, 6:1 methanol/oil ratio and a 0.75 wt% (KOH) catalyst concentration. The ultrasound assisted transesterification reactions performed at optimum conditions on the different oil samples led to higher yields of methyl esters (96.8, 98.32 and 97.65 % for WCO, SFO and SBO respectively) compared to methyl esters yields (90, 95 and 96 % for WCO, SFO and SBO respectively) obtained when using conventional batch procedures. A considerable increase in yields of the methyl esters in the ultrasound assisted reaction process were obtained at room temperature, in a remarkably short time span (completed in 30 min) and with a lower amount of catalyst (0.75 wt % KOH) while the results from the continuous jet loop process system showed even better results, at an optimum reaction condition of 25 min of reaction, a methanol: oil ratio of 4:1 and a catalyst amount of 0.5 wt%. This new jet loop process allowed an added advantage of intense agitation for an efficient separation and adequate purification of the methyl esters phase at a reduced time of 30 min. The use of homogeneous catalysts in conventional processes poses many disadvantages; heterogeneous catalysts on the other hand are attractive on the basis that their use could enable the biodiesel production to be more readily performed as a continuous process resulting in low production costs. Consequently, a solid base catalyst (KNO3/FA) prepared from fly ash (obtained from Arnot coal power station, South Africa) and a new zeolite, FA/Na-X synthesized from the same fly ash were used as solid base catalysts in the transesterification reactions in the conversion of a variety of oil feedstock with methanol to methyl esters. Since fly ash is a waste product generated from the combustion of coal for power generation, its utilization in this manner would allow for its beneficiation (as a catalytic support material and raw material for zeolite synthesis) in an environmentally friendly way aimed at making the transesterification process reasonably viable. Arnot fly ash (AFA) was loaded with potassium (using potassium nitrate as precursor) via a wet impregnation method while the synthesized zeolite FA/Na-X was ion exchanged with potassium (using potassium acetate as precursor) to obtain the KNO3/FA and FA/K-X catalysts respectively. Several analytical techniques were applied for characterization purposes. The results of the XRD and XRF showed that the AFA predominantly contained some mineral phases such as quartz, mullite, calcite and lime. The high concentration of CaO in AFA was apparent to be beneficial for the use of fresh fly ash as a support material in the heterogeneous catalysed transesterification reactions. XRD characterisation of KNO3/FA results indicated that the structure of KNO3/FA gradually changed with the increase in KNO3 loading. The catalyst function was retained until the loading of KNO3 was over 10 %. IR spectra showed that the KNO3 was decomposed to K2O on the fly ash support during preparation at a calcination temperature of 500 ºC. The CO2-TPD of the KNO3/FA catalysts showed that two basic catalytic sites were generated which were responsible for high catalytic abilities observed in the transesterification reactions of sunflower oil to methyl esters. On the other hand, XRD results for the as- received zeolite synthesized from AFA showed typical diffraction peaks of zeolite NaX. SEM images of the FA /NaX showed nano platelets unique morphology different from well known pyramidal octahedral shaped crystal formation of faujasite zeolites and the morphology of the FA /KX zeolite did not show any significant difference after ion exchange. The fly ash derived zeolite NaX (FA /NaX) exhibited a high surface area of 320 m2/g. The application of the KNO3/FA catalysts in the conversion reactions to produce methyl esters (biodiesel) via transesterification reactions revealed methyl ester yield of 87.5 % with 10 wt% KNO3 at optimum reaction conditions of methanol: oil ratio of 15:1, 5 h reaction time, catalyst amount of 15 g and reaction temperature 160 °C, while with the use of the zeolite FA/K-X catalyst, a FAME yield of 83.53 % was obtained for 8 h using the ion exchanged Arnot fly ash zeolite NaX catalyst (FA/KX) at reaction conditions of methanol: oil ratio of 6:1, catalyst amount of 3 % wt/wt of oil and reaction temperature of 65 ºC. Several studies have been carried out on the production of biodiesel using different heterogeneous catalysts but this study has been able to uniquely demonstrate the utilization of South African Class F AFA both as a catalyst support and as a raw material for zeolite synthesis; these catalyst materials subsequently applied sucessfully as solid base catalysts in the production of biodiesel. / South Africa

La croissance mondiale, économique et industrielle, ainsi que la rapide progression démographique des populations, ont fait augmenter la demande en énergie fossile. Ces dernières années, beaucoup de recherches ont été orientées vers de nouvelles ressources énergétiques qui peuvent remplacer les carburants fossiles conventionnels. Les biocarburants sont des carburants écologiques renouvelables, obtenus grâce à la transformation des matières grasses animales et végétales. Ils sont classés en tant que ressource idéale, non-toxique et renouvelable, substituant avantageusement le Diesel conventionnel. Dans cette optique, nous nous sommes intéressés à la production des biocarburants à partir d’une source végétale, non alimentaire, très abondante dans le bassin méditerranéen, en l’occurrence le pistachier lentisque, par deux procédés, l’un est chimique appelé transestérification et l’autre est thermochimique, la solvolyse. Les caractérisations des biocarburants conformément aux normes en vigueur, ont montré que les propriétés physico-chimiques sont comparables à celles du Diesel conventionnel. Un moteur Diesel monocylindre refroidi à l'air, a été utilisé pour évaluer les caractéristiques de la combustion de ces biocarburants, à 1500 tr/min, sous diverses conditions de charges du moteur. Les caractéristiques de la combustion (pression du cylindre, délai d’auto-inflammation, taux de dégagement de chaleur et durée de combustion) des biocarburants obtenus, sont comparées à celles du Diesel conventionnel. / The world economic and industrial growths, as well as the demographic rapid progression, have increased the fossil energy demand. These last years, much of researches were directed towards new energy resources which can replace the conventional fossil fuels. The biofuels are renewable ecological fuels derived from biomass; they are classified as an ideal resource, non-toxic and renewable component with respect to the conventional Diesel. In this context, we were firstly interested to the production of the biofuels starting from a non-edible vegetable source widely available in the Mediterranean basin which is the Pistacia Lentiscus using two processes. The first one is a chemical method named “transesterification” and the second one is a thermochemical procedure called “solvolysis”. The biofuels physicochemical properties, measured via standard methods, are similar to those of Diesel fuel. A single cylinder, naturally aspirated DI Diesel engine is operated at 1500 rpm with either pure produced biofuels or their blends with Diesel fuel for several ratios (50, 30 and 5 v%) and engine load conditions. The combustion parameters, their blends are compared with those of Diesel fuel.