Orientadores: Gonçalo Amarante Guimarães Pereira, Laudiene Evangelista Meyer / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-18T11:06:33Z (GMT). No. of bitstreams: 1 Curado_RaissaEstrela_M.pdf: 3964462 bytes, checksum: 28b1b79bbee3ec07ebb8a2d3fecebcef (MD5) Previous issue date: 2011 / Resumo: A necessidade do desenvolvimento de alternativas energéticas renováveis, limpas e de baixo custo, capazes de substituir o "petrodiesel" sem impactar a produção de alimentos, é a principal motivação para o desenvolvimento do projeto. Entre as alternativas, o cultivo de microalgas tem sido recorrentemente relatado como muito promissor. Microalgas são espécies unicelulares fotossintetizantes capazes de acumular lipídeos naturalmente. Entretanto, ainda não há cepas desenvolvidas para o uso industrial, havendo diversas barreiras tecnológicas a serem vencidas, como os altos custos de implantação e a dificuldade de encontrar organismos que aliem velocidade de crescimento e boa produtividade lipídica. Para o desenvolvimento do projeto selecionamos a espécie de microalga Neochloris oleoabundans devido à sua capacidade naturalmente superior em acumular lipídeos. O principal objetivo foi identificar estímulos ambientais capazes de induzir maior produção e acúmulo de cadeias carbônicas lipídicas nessa espécie e, então, iniciar análises moleculares nessas situações. Os primeiros cultivos de N. oleoabundans caracterizaram-se pelo crescimento muito lento nos diversos meios autotróficos testados, porém, ao final do projeto, percebemos que os cultivos cresciam com velocidade muito superior às culturas iniciais. Ao compilar os dados de crescimento obtidos nesses dois anos, vimos que as taxas de duplicação de N. oleoabundans foram elevadas em cerca de seis vezes nesse período. Acreditamos que houve seleção artificial de células mais velozes à medida que repicávamos os cultivos a fim de iniciar culturas novas. Para identificar condições capazes de induzir maior acúmulo lipídico, N. oleoabundans foi submetida a situações de estresse como privação de fósforo e nitrogênio. Observamos que a privação de nitrogênio foi capaz de desencadear aumento de teor lipídico muito expressivo. Então, sequenciamos o genoma e averiguamos a expressão gênica de algumas enzimas da via de biossíntese de ácidos graxos em privação de nitrogênio. Observamos também que cultivos feitos em meio heterotrófico mostravam-se rapidamente contaminados. A montagem do genoma pode dar indícios da natureza dessa contaminação recorrente, pois foram encontradas sequências de uma bactéria do gênero Brevundimonas. Ao investigar esse contaminante vimos que o mesmo pode estar em simbiose com a microalga, há relatos na literatura sobre simbioses dessa natureza, onde o procarioto fornece vitamina B12 e a microalga, matéria orgânica para o crescimento do mesmo. Encontramos enzimas dependentes dessa vitamina como cofator no genoma de N. oleoabundans, indicando que pode haver uma simbiose entre esses organismos. Devido aos bons resultados obtidos acreditamos que o estudo e manipulação a nível molecular dessa espécie podem torná-la potencialmente aplicável na indústria. O entendimento do mecanismo molecular de acúmulo lipídico sobre estresse, aliado ao potencial de seleção artificial de cepas velozes revelado, permite gerar conhecimento suficiente para agrupar em uma única espécie rápido crescimento e teor lipídico elevado / Abstract: Coal, petroleum and natural gas are cheap and may not run out soon. However, considering political and environmental implications associated with them, there appears to be no net economic benefit in its use. Therefore, sustainable alternatives are really necessary due to the global growing demand of energy. Among the alternatives, cultivation of microalgae has been reported as a promising technology. Algae use sunlight to produce biochemical energy via photosynthesis and its oil productivity and growth rates greatly exceeds that of vascular plants. Unlike the existing crop-derived biofuels, algae fuels can be produced without encroaching on food cropland. The technology is being intensively investigated by nearly every major and startups oil companies nowadays. However, there are no species developed for industrial use and there are several technological barriers to overcome. In this study we investigated the microalga Neochloris oleoabundans, selected for its naturally higher ability to accumulate lipids. Initially, N. oleoabundans growth rates were very low. We decreased by six times the cell doubling time, we believe that occurred artificial selection of faster growing cells during the master's period. Nitrogen starvation led to great increases in cellular lipid content. Real-time PCR experiments show that some key enzymes of fatty acid biosynthesis are differentially expressed in nitrogen starved cultures. The genome of N. oleoabundans was sequenced using Solexa® technology and preliminary analysis show the presence of a bacterium associated with the microalga. We believe that there is a symbiotic relationship between them, since the alga needs vitamin B12 despite being not capable of producing it. Our analysis show that N. oleoabundans is a very promising strain. The excellent response to nitrogen starvation and knowledge acquired with genomic approach led us to a better understanding of N. oleoabundans metabolism, indicating that this specie may be suitable for industrial application / Mestrado / Genetica de Microorganismos / Mestre em Genética e Biologia Molecular

Orientador: Silvania Lanfredi / Banca: Ana Maria Pires / Banca: Luiz Henrique Dall'Antonia / Resumo: Neste trabalho foram investigadas a síntese, caracterização estrutural e espectroscópica e a análise do potencial catalítico de catalisadores do tipo perovskita SrTiO3 e das perovskitas duplas de Sr1-xKxTiCux/2O3, onde x = 0,2 , 0,3 e 0,5, na preparação do biodiesel via rota etílica. A partir da estrutura hospedeira do titanato de estrôncio SrTiO3 foram investigadas as soluções sólidas contendo átomos de cobre e potássio com as seguintes estequiometrias: Sr0,8K0,2TiCu0,1O3, Sr0,7K0,3TiCu0,15O3 e Sr0,5K0,5TiCu0,25O3, preparadas por síntese química pelo método Poliol Modificado. Os sistemas investigados foram avaliados utilizando as técnicas de análise térmica (ATG) e calorimetria exploratória diferencial (DSC), microscopia eletrônica de varredura (MEV), difração de raios X (DRX) e espectroscopia vibracional de absorção na região do infravermelho. Os parâmetros estruturais dos sistemas investigados foram determinados pelo refinamento utilizando o método de Rietveld, considerando o grupo espacial Pm m. A partir da determinação dos parâmetros cristalográficos foi construída a célula unitária do SrTiO3 utilizando o programa Diamond 3.2. O estudo catalítico foi realizado a partir da catálise heterogênea, com a adição das nanopartículas em solução contendo óleo vegetal e álcool etílico. O processo de transesterificação foi realizado em um reator de escala laboratorial, desenvolvido junto ao Laboratório de Compósitos e Cerâmicas Funcionais, com sistema de agitação e temperatura controlada. Neste processo, os principais produtos formados foram o biodiesel e o glicerol residual. Ao longo da execução dos experimentos foram controlados os parâmetros do processo, como o tempo da reação, concentração do catalisador, temperatura e o grau de agitação. Ao final da reação foi possível filtrar o catalisador e reprocessá-lo para uma nova reação, recuperar o álcool etílico e calcular o rendimento ... / Abstract: In this work was investigated the synthesis, structural and spectroscopic characterization and the analysis of the catalytic potential of SrTiO3 of perovskita structure and of perovskites doubles Sr1-xKxTiCux/2O3, where x = 0.2, 0.3 and 0.5, in the biodiesel preparation by ethyl route. From the host structure of strontium titanate SrTiO3 were investigated solid solutions containing copper and potassium atoms with the following stoichiometry: Sr0.8K0.2TiCu0.1O3, Sr0.7K0.3TiCu0.15O3 and Sr0.5K0.5TiCu0.25O3, prepared by chemical synthesis using Modified Polyol method. The systems investigated were evaluated using the techniques of thermal analysis (TGA) and differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared spectroscopy (FTIR). The structural parameters of the investigated systems were determined by the refinement using the Rietveld method, considering the space group Pm m. From the determination of the crystallographic parameter was build the of unit cell of the SrTiO3 using the program Diamond 3.2. The catalytic study was performed from heterogeneous catalysis, with addition of nanoparticles in solution containing vegetable oil and ethyl alcohol. The transesterification process was carried out in a reactor laboratory scale, developed at the LaCCeF, with stirring and controlled temperature. In this process the main products were biodiesel and residual glycerol. During the experiments were controlled the process parameters such as reaction time, catalyst concentration, temperature and stirring degree. In the end of the catalysis reaction was possible to filter and reprocess it to a new reaction, recover the ethanol and calculate the yield of biodiesel from the characterization by gas chromatography coupled to mass spectrometry. The results showed that the Sr0.5K0.5TiCu0.25O3 catalyst is the most efficient for obtention of biodiesel presenting a high conversion in the ... / Mestre

M. Tech. (Department of Chemistry, Faculty of Applied And Computer Sciences), Vaal University of Technology. / Biodiesel has an ability to solve the problem associated with the use of fossil fuels as a source of energy. The aim of this study was to produce biodiesel from waste cooking oil (WCO) by transesterification, catalysed with potassium hydroxide (KOH) supported on attapulgite (ATP) clay as the heterogeneous catalyst. WCO was used on the basis that it is one of the cheapest feedstocks for biodiesel production, is readily available and can minimise environmental impact. ATP clay was first crushed and sieved to particle sizes of ≤ 90 μm and subsequently treated with hydrochloric acid (HCl) to remove impurities. The KOH supported ATP catalyst was prepared through ion exchange method by soaking ATP into KOH solution, dried in an oven and later calcined at 400 ℃ in a furnace. The prepared catalyst and ATP clay were characterised using Hammett indicator to determine the basic strength of the catalyst. XRF and EDX were used to determine the elemental composition of the catalyst whilst XRD was used to determine the crystallinity of the ATP after modification. The functional groups of ATP were determined by FTIR. BET was utilised to determine the changes on the surface area, pore volume and pore diameter of ATP and on the other hand, SEM was used to determine the morphological changes on the surface of ATP. The XRD, FTIR, BET AND SEM-EDX showed that addition of potassium caused changes on the surface of the ATP. The optimal conditions for the transesterification reaction of waste cooking oil with methanol were found to be oil-to-methanol molar ratio of 1:15, 3wt% catalyst amount, 65 ℃, 3 h of a reaction time, at 200 rpm stirring rate and 94 % biodiesel yield was obtained. After the catalyst was reuse three consecutive times, the decrease in biodiesel yield was observed (Figure 17) after each cycle. However, the 5MKOH/ATP catalyst is heterogeneous and can be used to transesterify WCO with good yield.

Thesis submitted in 50 % completion of the degree of Master of Management in the field of Public and Development Management at the University of the Witwatersrand, Johannesburg. 20 June 2016 / In response to the ever increasing problems associated with climate change, and greenhouse gas emissions, many countries in the world are developing and adopting climate change resilient policies that support green economy. Green economy sector in South Africa has not as yet received much expected attention as a key sector to address economic and environmental problems. The use and the production of renewable fuels, such as biodiesel are known to have significant economic and environmental benefits. However, progress in the production of biodiesel is hampered by limits imposed by government on the use of fresh vegetable extracted oils for production of biodiesel, mainly due to challenges on food security; and the impact this will have on food prices. In recent years recycling has become an important tool to address waste problems; pollution control; and socio-economic problems such as joblessness, poverty and social inequity. Used cooking oil has always been considered waste and an environmental burden. Therefore through technology advancement of recycling, wastes such as used cooking oil have become useful resources for biodiesel production. This research is about the challenges in recycling used cooking oil to produce biodiesel. The study recommended that in order to address challenges facing sustainability of our environment, and high unemployment rate; small recycling industries such as those operating in Polokwane will need government support such as biodiesel sector policies and regulations, to encourage investment in the biodiesel value chains in a way that will lead to the achievement of green economy goals. / MT2016

Thesis (MBA)--Stellenbosch University, 2012. / Bioethanol and biodiesel are currently the main biofuels. The United States of America and Brazil are the major bioethanol producers from maize and sugar cane respectively. European and Asian countries produce and consume biodiesel as transportation fuel. Generally, governments want to avoid importing biofuels, since this erodes the advantage of fuel security from growing fuel locally. There are however opportunities for many African countries to export to Europe and the United States of America, since they have preferential import tax exemption agreements with African countries. Sub-Saharan Africa has large potential to produce biomass. Inherently, South Africa has poor potential to produce biomass, due to the climatic conditions and water scarcity. However, South Africa has infrastructure, skills, commercial farmers and, importantly, government policy on biofuels. These advantages should be leveraged to optimise gains from a biofuel industry. A biofuels industry holds potential in terms of job creation and rural development gains, apart from the advantages of fuel security, greenhouse gas (GHG) emission reductions, stimulation of the agricultural sector, and reduced fuel imports with the balance of payment advantages. The South African government aims to develop rural communities in former homeland areas. If degraded land in these areas is recovered and used for production of biofuels, the environmental benefits are immediate and substantial. Fuel crop production in these areas does not compromise food security nor does it result in further deforestation. Creating jobs in rural areas can contribute to reduction of poverty. The Department of Minerals and Energy (DME) published its strategy in 2007. This excluded maize as permitted bioethanol feedstock, it sets a two per cent liquid fuels penetration target, and gave fuel tax exemptions for biodiesel and bioethanol. The biofuels would be distributed through voluntary low concentration blending into petroleum products by oil companies. The industry would be regulated and producers require licensing through the South African Revenue Service (SARS). The license conditions were mainly related to the type of feedstock, where it was produced, volumes produced, local consumption, environmentally friendliness, compliance with broad based black economic empowerment requirements and it should not compete with food sources. The strategy is up for review after the initial five years phase. Currently there are no commercial bioethanol fuel production plants in South Africa and only some small scale biodiesel production plants with very limited outlets to consumers. With all the apparent advantages, why is nothing happening in the industry? Business is not showing interest, proving that the economic conditions are not favourable. The government wants to control the production side to maximise the gains from it, but instead of assisting the industry, it has practically inhibited it from getting started. The consumers must also be prepared to accept the new fuels. Awareness, education and a culture of sustainable use are vital to create the required market. This is an exciting industry with potential benefits to South Africa and its society as a whole, but the fundamental elements of business must be in place in order for it to become self-sustainable.

Submitted in fulfillment for the requirements for the degree of Doctor of Technology: Biotechnology, Durban University of Technology, Durban, South Africa, 2015. / Main focus of this study is to investigate the enzymatic-conversion of microalgal lipids to biodiesel. However, preceding steps before conversion such as drying of microalgal biomass and extraction of lipids were also studied. Downstream processing of microalgae has several challenges and there is very little literature available in this area. S. obliquus was grown in the pilot scale open pond cultivation system for biomass production. Different techniques were studied for biomass drying and extraction of lipids from harvested microalgal biomass. Effect of these drying and extraction techniques on lipid yield and quality was assessed. Energy consumption and economic evaluation was also studied. Enzymatic conversion of microalgal lipids by extracellular and whole cell lipase application was investigated. For both applications, free and immobilized lipases from different sources were screened and selected based on biodiesel conversion. Process parameters were optimized using chosen extracellular and whole cell lipases; also step-wise methanol addition was studied to improve the biodiesel conversion. Immobilized lipase was studied for its reuse. Final biodiesel was characterized for its fuel properties and compared with the specifications given by international standards. Enzymatic conversion of microalgal lipids was compared with the conventional homogeneous acid-catalyzed conversion. Enzymatic conversion and chemical conversion were techno-economically investigated based on process cost, energy consumption and processing steps. Freeze drying was the most efficient technique, however at large scale economical sun drying could also be selected as possible drying step. Microwave assisted lipid extraction performed better compared to sonication technique. Immobilized P. fluorescens lipase in extracellular application and A. niger lipase in whole cell application showed superior biodiesel conversion. The extracellular immobilized P. fluorescens lipase showed better biodiesel conversion and yields than the immobilized A. niger whole cell lipase. Both the enzyme catalysts showed lower biodiesel conversion compared to conventional chemical catalyst and higher processing cost. However, techno-economic analysis showed that, the reuse potential of immobilized lipases can significantly improve the economics. Fewer purification steps, less wastewater generation and minimal energy input are the benefits of enzymatic route of biodiesel conversion. Microalgae as a feedstock and lipase as a catalyst for conversion makes overall biodiesel production process environmentally-friendly. Data from this study has academic as well as industrial significance. Conclusions from this study form the basis for greener and sustainable scaling-up of microalgal biodiesel production process. / D

Thesis (M.S.)--Mississippi State University. David C. Swalm School of Chemical Engineering. / Title from title screen. Includes bibliographical references.

A purificação do biodiesel originado do processo de produção por transesterificação de óleos e gorduras requer a remoção de resíduos de glicerina. Como metodologia de cálculos correlações que dão origem a diagramas de dimensionamento foram transformados em modelos matemáticos envolvendo importantes números adimensionais. Apresenta-se uma estratégia de separação da glicerina dispersa no biodiesel utilizando um hidrociclone otimizado da família Rietema. Foram simuladas e analisadas as condições de separação da mistura biodiesel-glicerina, etapa integrante do processo de produção desse biocombustível por transesterificação de óleos e gorduras, em condições operacionais otimizadas e não otimizadas. A estratégia de otimização foi o uso de correlações econômicas e geométricas, as quais levaram à obtenção de um custo mínimo. Uma das etapas mais importante do processo de produção de biodiesel é a de sua purificação. Um hidrociclone do tipo convencional foi proposto para a referida etapa. A estratégia usada para elaboração da função objetivo foi composta de três termos: custo de aquisição, custo de operação e o custo associado a não coleta do biodiesel, todas como função do diâmetro do equipamento. Como programas de cálculos para dimensionamento e otimização foram utilizadas a planilha eletrônica Excel e sua ferramenta solver. Os resultados mostraram que a estratégia e otimização forneceram valores de dimensionamento muito próximos dos de condição não otimizadas, demonstrando que a mesma pode ser utilizada como reforço, numa época em que os critérios econômicos são importantes justificativas de investimentos nas melhorias dos processos produtivos / The purification of biodiesel of the production process by transesterification of oils and fats require the removal of glycerin waste. It presents a strategy for separation of glycerin dispersed in biodiesel using an optimized hydrocyclone of the Rietema family. As calculation methodology correlations that lead to the sizing diagrams were converted into mathematical models involving significant dimensionless numbers. It presents a strategy for separation of glycerin dispersed in biodiesel using an optimized hydrocyclone of the Rietema family. They had been simulated and analyzed the conditions of separation of the mixture biodiesel-glycerin, integrant stage of the process of production of this biofuel of separation of oils and fats, in optimized and not optimized operational conditions. The optimization strategy was the use of economic and geometric correlations, which had led to the attainment of a minimum cost. One of the stages most important of the process of production of biodiesel is of its purification. One hidrociclone of the conventional type was considered for the related stage. The used strategy for elaboration of the objective function was composed of three terms: cost of acquisition, cost of operation and the associated cost does not collect of biodiesel, all as function of the diameter of the equipment. As programs of calculations for sizing and optimization the electronic spread sheet Excel and its tool had been used to solve. The results had shown that the strategy and optimization had supplied values of not optimized sizing very next to the ones of condition, demonstrating that the same one can be used as reinforcement, at a time where the economic criteria are important justifications of investments in the improvements of the productive processes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho foi desenvolvido um método empregando a técnica de microextração líquido-líquido dispersiva em fase reversa (RP-DLLME) como preparo de amostra, para extração e pré-concentração de Na, K, Ca e Mg em amostras de biodiesel. A determinação dos analitos foi feita por espectrometria de absorção atômica com chama (F AAS), operando no modo emissão para Na e K e absorção para Ca e Mg. Para executar a etapa de extração/pré-concentração dos analitos empregou-se uma mistura de dois solventes, um dispersor e um extrator, que foi adicionada em cada amostra em volumes e concentrações adequados. A extração dos analitos ocorreu após adição da mistura de dispersor-extrator e a fase sedimentada formou-se mediante centrifugação. Foram avaliados alguns parâmetros sobre a eficiência da extração como: massa de amostra (3, 5, 10 e 20 g), tipos de solvente dispersor e proporção (isopropanol, 60, 65, 70, 75, 80, 85% (v/v)), concentração da solução extratora (HNO3 0,5; 1; 1,5 e 2 mol L-1 (v/v)), volume da fase extratora (0,5; 1,0 ; 1,5 e 2 mL), tempo de centrifugação (5, 10 e 15 min) e temperatura (45, 55, 65 e 75 °C). Para todos os parâmetros avaliados e ajustados, foi feita a adição dos analitos (1,0 μg) nas amostras com dois padrões multielementares de biodiesel (2,5 e 20 μg g-1 de Na, K, Ca e Mg), sendo os resultados expressos como recuperação (%). Para a determinação dos analitos por F AAS, foi feita calibração externa com soluções de referência aquosas. As curvas de calibração para Na, K, Ca e Mg foram lineares entre 0,1 e 2,0 mg L-1 Os limites de quantificação para Na, K, Ca e Mg para este método foram 0,04; 0,02; 0,05 e 0,08 mg kg-1, respectivamente. A exatidão foi avaliada por meio de ensaios de recuperação e os valores obtidos entre 94 e 108% com RSD inferior a 5% para todos os analitos. O método foi aplicado a cinco amostras diferentes de biodiesel produzidos a partir de diferentes matérias-primas. O método desenvolvido foi considerado viável para a determinação de Na, K, Ca e Mg em biodiesel, atendendo os requisitos da Legislação Brasileira, que determina limites máximos de 5 mg k-1 para a soma de Na e K e o mesmo limite para a soma de Ca e Mg. Como principais aspectos que caracterizam o método, destaca-se a simplicidade de operação, o baixo custo, baixo consumo de reagentes de acordo com os princípios da Química Verde, uso de equipamentos de fácil operação, alta frequência analítica, além de baixos limites de quantificação para determinação dos analitos por F AAS. / This research developed a method for employing reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) as sample preparation for the extraction and pre-concentration of Na, K, Ca and Mg in biodiesel samples. The determination of analytes were executed through flame atomic absorption spectrometry (F AAS), operating in emission mode for Na and K and absorption mode for Ca and Mg. The extraction/pre-concentration step of the analytes was performed using a mixture of two solutions, a dispersing and an extractor, which were added to each sample in appropriate volumes and concentrations. The extraction of analytes occurred after the addition of the dispersing-extractor settled-phase mixture formed via centrifugation. Some parameters were evaluated on the extraction efficiency, such as: sample mass (3, 5, 10 and 20 g), different kinds of dispersant solvent and proportion (isopropanol, 60, 65, 70, 75, 80, 85% (v/v)), concentration of the extraction solution (HNO3 0,5; 1;1,5 and 2 mol L-1 (v/v)), the volume of extraction phase (0.5; 1.0; 1.5 and 2.0 mL), centrifugation time (5, 10 and 15 min) and temperature (45, 55, 65 and 75 °C). All the studied and adjusted parameters were made by analytes addition (1.0 μg) on the samples with two biodiesel multielemental standards (2.5 and 20 μg g-1 Na, K, Ca and Mg) whose results were expressed in recovery percentage (%). Due to the determination of analytes by F AAS, an external calibration was performed with aqueous reference solution. The calibration curves for Na, K, Ca and Mg were linear between 0.1 and 2.0 mg L-1. The quantification limits of Na, K, Ca and Mg for this method were respectively: 0.04; 0.02; 0.05 and 0.08 mg kg-1. The accuracy of the proposed method was assessed by recovery experiments and the values obtained were between 94% and 108% with RSD less than 5% for all analytes. The developed method was then applied to five different samples of biodiesel produced from different raw materials. Hence, the developed method was considered viable for the determination of Na, K, Ca and Mg in biodiesel, in accordance with the requirements of Brazilian regulation, which sets maximum limits of 5 mg k-1 for adding Na and K and the same limit for adding Ca and Mg. The main aspects that characterize this method are its simplicity in operation, low cost, low consumption of reagents according to the principles of green chemistry, easy operation equipment use, high analytical frequency, and low limits of quantification for the determination of analytes for F AAS.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho descreve a avaliação do processo oxidativo do biodiesel metílico da macaúba, na ausência e na presença dos antioxidantes sintéticos e naturais. O biodiesel foi obtido por meio da transesterificação do óleo da amêndoa da Macaúba utilizando ácido p-toluenossulfônico como catalisador. Por meio de análises termogravimétricas foi possível verificar o teor de éster presente no biodiesel. O biodiesel obtido via reação de transesterificação do óleo da amêndoa da Macaúba foi submetido a testes acelerados de degradação térmica por um período de 6 horas a 150 ºC e ao teste de oxidação em estufa por um período de 30 dias a 65 ºC com as seguintes concentrações de BHT: 100, 500, 1000 e 5000.Os resultados de índice de acidez, peróxido, iodo e espectroscopia na região do IV comprovaram que ambos os métodos de oxidação foram capazes de degradar o biodiesel e demonstraram que o BHT foi capaz de minimizar a oxidação no biodiesel apenas na concentração de 5000 ppm. Ensaios com β-naftol e extrato de compostos fenólicos proveniente do bagaço de uva foram realizados empregando o teste acelerado de degradação. Os testes com as amostras contendo β-naftol foram realizados utilizando as concentrações de 1000 e 5000 ppm do antioxidante e em ambas as concentrações o β-naftol apresentou potencial em inibir a oxidação das amostras, sendo os melhores resultados atribuídos a concentração de 5000 ppm. O extrato do bagaço de uva foi obtido pela extração em Soxhlet e ultrassom. O extrato obtido por Soxhlet foi submetido aos testes utilizando concentrações de 1000 e 5000 ppm equivalente aos compostos fenólicos, também foi preparada uma amostra com 5000 ppm de extrato obtido pela extração por ultrassom. Os resultados para esse teste demonstraram que os extratos não foram eficazes em inibir a oxidação nas amostras. Entre os ensaios com extrato o de 5000 ppm por ultrassom apresentou os menores índices de acidez, peróxido e iodo. Estudo com o uso desse antioxidante em maiores concentrações se torna relevante. Por fim ao comparar todos os antioxidantes analisados, o β-naftol foi considerado o mais eficaz. / This work is about the evaluation of processing methyl oxidative biodiesel from macaúba, with and without natural and synthetic antioxidants. The biodiesel was obtained from the transesterification of the macaúba’s almond oil and using p-toluenesulfonic as a catalyst. It could be verified through thermogravimetric analysis the ester content in the biodiesel. The biodiesel obtained thru the transesterification of the macaúba’s almond oil was subjected to accelerated tests of thermal degradation for a period of 6 hours at 150 ° C and the oxidation test in the stove for 30 days at 65 ° C with the following BHT concentrations: 100, 500, 1000 and 5000. The acidity index results, peroxide, iodine and IV spectroscopy in the region showed that both oxidation methods were capable of degrading biodiesel and demonstrated that the BHT was able to minimize oxidation of biodiesel only at a concentration of 5000 ppm. Trials with β-naphthol and extract phenolics from grape pomace were performed using the accelerated degradation tests. The tests with samples containing β-naphthol were carried out using concentrations of 1000 and 5000 ppm of the antioxidant and at both concentrations the β-naphthol has the potential to inhibit oxidation of the samples, with the best results attributed to concentration of 5000 ppm. Grape pomace extract was obtained by extracting in a Soxhlet and ultrasound .The extract obtained by Soxhlet was subjected to tests using concentrations of 1000 and 5000 ppm equivalent of phenolic compounds, it was also prepared a sample with 5000 ppm of extract obtained by extraction by ultrasound. The results for this test showed that the extracts were not effective in inhibit oxidation in samples. Between rehearsals with the extract of 5000 ppm ultrasound showed the lowest acidity index, peroxide and iodine. Study with the use of this antioxidant in higher concentrations is relevant. Finally when comparing all antioxidants analyzed, β-naphthol was considered the most effective.