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Le cerveau humain est un organe très métaboliquement actif. Cet énorme besoin énergétique l’expose à un risque accru de détérioration causée par un dérèglement de ce métabolisme. Dans la phase précoce de la maladie d’Alzheimer, un hypométabolisme cérébral du glucose est observé. Cette carence énergétique serait à l’origine des détériorations observée lors du développement de cette maladie. Le cerveau a accès à une autre source endogène d’énergie : les cétones. Les cétones sont particulièrement importantes pour le cerveau puisqu’il ne possède pas la capacité d’utiliser les acides gras comme source énergétique à l’instar des autres organes. Les cétones sont issues de la β-oxydation hépatique des acides gras. Ils sont produits en situation de jeûne lorsque les niveaux circulants de glucose et d’insuline sont bas. Les cétones se sont déjà montré efficaces dans le traitement de divers troubles neurologiques comme l’épilepsie. Par contre, outre les diètes cétogènes et le jeûne prolongé, il n’existe pas de traitement efficace pour maintenir une cétonémie modérée chez l’adulte. Le métabolisme énergétique cérébral en situation de cétose modérée reste encore mal compris dans cette population. Les travaux de cette thèse se sont donc concentrés à étudier la possibilité d’une combinaison d’approche nutritionnelle et pharmacologique afin de stimuler la cétogenèse chez l’adulte. Ils ont aussi exploré les changements de métabolisme cérébral chez l’adulte durant une cétose modérée. L’objectif de la première étude était d’étudier le potentiel du bezafibrate à stimuler la cétogenèse induite par une supplémentation en triglycérides de moyennes chaînes (MCT). Cette première étude a démontré que le bezafibrate avait peu d’effet sur la stimulation de la cétogenèse induite par les MCT et que le facteur limitant dans cette stimulation était donc la disponibilité des substrats et non la capacité cétogène des cellules hépatiques. L’objectif de la seconde étude était d’étudier les changements de capture des cétones et du glucose au cerveau durant un état de cétose modérée chez l’adulte. Les résultats de cette deuxième étude ont montré que la capture des cétones au cerveau est directement proportionnelle à leur concentration plasmatique. Cette étude a aussi démontré que la capture cérébrale des cétones était directement reliée à leur concentration plasmatique alors que la capture cérébrale du glucose est modulée par les besoins énergétiques du cerveau. Une stimulation cétogénique chez des personnes atteintes de déclin cognitif pourrait donc aider à rétablir la balance énergétique et ralentir l’apparition des symptômes chez ces personnes mais cet effet devra être étudié dans une étude ultérieure. / Abstract : The human brain is the most metabolically active organ of the body. This high need for energy exposes it to an increase risk in case of hypometabolism. Such a glucose hypometabolism is seen during the early stages of Alzheimer’s disease. This factor is believed to be one of the cause of the disease. Ketones are the main alternate substrate for the human brain. Ketones are particularly important since, unlike other organs, the brain can not use fatty acids as alternative fuel. Ketones are mainly produce through β-oxidation of fatty acid by the liver. This happens mainly during fasting when circulating levels of glucose and insulin are low. Studies have shown that ketones can have a therapeutic effect in a variety of neurological diseases, mainly epilepsy and Alzheimer’s disease. Nevertheless, apart from ketogenic diet and prolonged fasting, there is currently no effective ways to induce and maintain moderate ketosis in adults. Brain energy metabolism under moderate ketosis remains also misunderstood in this population. This thesis aimed look at the effect of a combination of a pharmacological treatment and a nutritional supplementation to induce moderate sustain ketosis in adults. It also studied the effect of a moderate ketosis on brain energy metabolism in adults. The aim of the first study was to study the effect of a pharmacological treatment, bezafibrate, on the potentiation of the ketogenic effect induced by a medium-chain triglycerides (MCT) supplementation. The results of this study that bezafibrate had little effect on the ketosis induced by a MCT supplementation and, therefore, that the limiting factor in human ketosis was not the liver cells capacity to produce ketones but the availability of substrates for ketogenesis. The aim of the second study was to study the impact of a nutritional moderate ketosis on brain glucose and ketone uptake. The results of this study showed a direct correlation between brain ketone uptake and plasma ketone concentrations. This study also showed that brain ketone uptake is regulated by blood ketone concentration whereas brain glucose uptake is regulated by the brain energy needs. Further studies should then look if such a moderate ketosis induced in cognitively impaired patients could re-equilibrate the energy balance in the brain and then slow the apparition of clinical symptoms in this population.

Forty Sprague Dawley rats were randomly placed in five groups with eight rats per group. Each group varied in dietary composition for fiber type and carbohydrate source. Groups one and two received oat fiber and either sucrose or corn starch as the carbohydrate source. Groups three and four received corn bran as the fiber source and either sucrose or corn starch as the carbohydrate source. Group five (considered the control group), received Purina standard rat chow. Analysis of variance showed only significant differences for food intake, and the control group had a significantly higher food intake. Weight gain, serum cholesterol and triglyceride levels showed no significant differences.

Orientador: Luis Artur Loyola Chardulo / Coorientador: Rogério Abdallah Curi / Banca: Simone Cristina Méo Niciura / Banca: Josineudson Augusto II de Vasconcelos Silva / Resumo: O objetivo deste estudo foi estimar as frequências dos polimorfismos nos genes DGAT1 (sequência de 18 nucleotídeos na região promotora - VNTR), ANK1 (novo polimorfismo identificado na região regulatória), TCAP (AY428575.1:g.346G>A) e MYOG (NW_001501985:g.511G>C) e associá-los a características relacionadas à qualidade de carne e carcaça em bovinos Nelore (Bos indicus). Foram utilizados 600 machos, terminados em confinamento com idade inferior a dois anos, com informações de desempenho e genealogia. Os animais foram abatidos em frigoríficos comerciais, onde foram obtidas amostras individuais do músculo Longissimus dorsi para extração do DNA e realização das análises fenotípicas da carne. A genotipagem foi realizada por meio da técnica da PCRRFLP, com exceção do VNTR do gene DGAT1 que foi apenas amplificado pela PCR. Por meio da análise do tamanho dos fragmentos em gel de agarose, foram determinados os genótipos dos indivíduos para o cálculo das frequências alélicas e genotípicas. O estudo de associação com o peso de carcaça quente, área de olho de lombo (AOL), espessura de gordura subcutânea, força de cisalhamento, perdas por cocção (perdas), coloração instrumental (L*, a*, b*), porcentagem de gordura intramuscular (GIM) e índice de fragmentação miofibrilar foi realizado por meio do procedimento GLM do SAS®. O alelo B do gene ANK1 foi associado ao aumento da coloração vermelha (a*) da carne (p<0,05). No gene DGAT1, os alelos 5R, 6R e 7R foram associados (p<0,05) ao aumento da GIM, à redução das perdas e ao aumento da AOL, respectivamente. O SNP do gene TCAP não foi polimórfico e os alelos do gene MYOG não foram associados a nenhuma das características testadas. Os resultados obtidos indicam que os genes DGAT1 e ANK1 podem ser utilizados na seleção de animais Nelore para qualidade de carne e carcaça / Abstract: The aim of this study was to estimate the polymorphism frequencies of the genes DGAT1 (sequence of 18 nucleotides at the promoter region - VNTR), ANK1 (new polymorphism identified at the regulatory region), TCAP (AY428575.1:g.346G>A) and MYOG (NW_001501985:g.511G>C) and associate them to carcass and meat quality in Nellore cattle (Bos indicus). It was used 600 males, finished at feedlot under two years old, with performance and genealogy information. Slaughter was carried out in commercial abattoir where individual samples were obtained from Longissimus dorsi for DNA extraction and meat analysis. Genotyping was performed by PCR-RFLP, with exception for the VNTR of gene DGAT1 that was only amplified by PCR. By analyzing the fragment size on the agarose gel, the genotypes of the animals were determined for calculation of allele and genotype frequencies. The associations study with hot carcass weight, ribeye area (REA), back fat thickness, shear force, cooking loss (CL), meat color (L*, a*, b*), percentage of intramuscular fat (IF) and myofibrillar fragmentation index was performed using the GLM procedure of SAS®. The allele B from ANK1 gene was associated to higher redness (a*) of meat (p<0.05). The alleles 5R, 6R and 7R from DGAT1 VNTR gene were associated (p<0.05) to increased IF, reduced CL and increased REA, respectively. The SNP of TCAP gene was not polymorphic and MYOG alleles were not associated to any of the tested characteristics. Results indicate that DGAT1 and ANK1 genes can be used in the selection of Nellore cattle for carcass and meat quality / Mestre

Com a utilização de quatro potros, com a idade entre 13 a 16 meses, e peso médio de 288±7,68 Kg, recebendo dieta composta de feno de gramínea e concentrado, objetivando-se analisar o efeito da inclusão de diferentes tipos de gordura de origem animal, de origem vegetal e óleo mineral. Avaliou-se a aceitabilidade das dietas, o coeficiente de digestibilidade aparente da Matéria Seca, Matéria Orgânica, Proteína Bruta, Extrato Etéreo, Fibra insolúvel em Detergente Neutro e Fibra insolúvel em Detergente Ácido, utilizando a metodologia de coleta total de fezes, foi observado o efeito da suplementação sobre níveis de gorduras nos valores plasmáticas (Triglicérides, Colesterol e de suas frações VLDL-C, HDL-C, LDL-C). O delineamento experimental utilizado foi o Quadrado Latino 4X4, para separar os efeitos de tratamento foram utilizados três contrastes ortogonais, C1: óleo mineral vs dieta controle; C2: gordura animal vs gordura vegetal e C3: gordura animal+ gordura vegetal vs dieta controle. Os resultados demonstrados nesse experimento foram que a aceitabilidade não foi observada diferença entre os tratamentos, que o contraste ortogonal C1 apresentou resultado significativo para digestibilidade de MS e MO e EE, e o contraste C3 apresentou valor significativo para EE, para os valores plasmáticos o contraste ortogonal C1 apresentou valor significativo para HDL-C, sendo que os outros contrastes não apresentaram variação estatística. Podemos concluir que a adição de óleo mineral afeta a digestibilidade da MS, MO e EE se comparado ao controle, não afetando a digestibilidade da PB, FDN e FDA, que a adição de gordura vegetal não se diferencia com a gordura animal quanto a digestibilidade dos nutrientes aqui mensurados e a adição de gordura vegetal e animal altera a digestibilidade do EE em comparação com o controle. Quanto aos valores plasmáticos observamos que a adição de óleo mineral alterou os valores de HDL-C em relação à dieta controle, e os outros contrastes não obtiveram resultados significativos em relação aos valores plasmáticos. / Four foals, aging from 13 to 16 months and with average weight of 288 ± 7.68 kg were used in this study, in order to evaluate the effects of the inclusion of different types of fat from animal source, vegetable fat and mineral oil. The basis of the diet of experimental animals was grass hay and concentrate. It was evaluated the acceptability of the diets, the coefficient of apparent digestibility of Dry Material (DM), Organic Matter (OM), Crude Protein (CP), Extract Etéreo (EE), Neutral detergent fiber (NDF) and acid detergent fiber (ADF), by means of the methodology of total feces collection. It was also observed the effect of supplementation on levels of plasma fat (Triglycerides, Cholesterol and its fractions, VLDL-C, HDL-C, LDL-C). The experimental design was a 4X4 Latin Square; three orthogonal contrasts were carried out in order to evaluate the effects of treatments: C1: mineral oil vs control diet; C2: animal fat vs. vegetable fat and C3: animal fat + vs vegetable fat diet control. It was demonstrated that the acceptability did not differ between treatments; contrast C1 showed significant results for digestibility of MS and MO and EE, and the contrast C3 showed significant result for EE. In regard of the values of plasma fat, contrast C1 presented significant value for HDL-C; contrast C2 and C3 did not show statistically significant variation. In conclusion, the addition of mineral oil affected the digestibility of DM, OM and EE, but did not affect the digestibility of CB, NDF and ADF; the addition of vegetable fats did not produce any variation in comparison with animal fats on the digestibility of the measured nutrients and the addition of both vegetable and animal fat altered the digestibility of EE. It was also observed that the addition of mineral oil changed the values of HDL-C compared with the control diet, and either contrasts C1 or C2 did not show significant differences on levels of plasma fat.

Introdução: Os fitoesteróis são indicados no tratamento da hipercolesterolemia. Embora sua ação sobre a redução do colesterol já tenha sido exaustivamente estudada, não se encontra bem elucidada na literatura, a forma como atua sobre biomarcadores inflamatórios e endoteliais em indivíduos hipercolesterolêmicos. Objetivo: Avaliar o efeito do fitoesterol adicionado ao leite de soja sobre as concentrações plasmáticas de lípides e biomarcadores, além de alterações em vias transcricionais envolvidos na patogênese da aterosclerose em células linfomononucleares em indivíduos moderadamente hipercolesterolêmicos. Metodologia: Foram estudados 38 pacientes, recrutados no Ambulatório do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Inicialmente, os pacientes foram submetidos a um período basal de três semanas para avaliar a aderência e tolerabilidade ao leite de soja padrão (Placebo). Foram orientados a manter os hábitos alimentares e a atividade física. Receberam 400 mL/dia de leite de soja padrão ou enriquecido com fitoesteróis (1,6 g/dia) por dois períodos de quatro semanas em que o estudo foi randomizado, cego e cruzado. Resultados: O peso corporal foi mantido durante o estudo. O tratamento com fitoesterol reduziu o colesterol total em 5,5 % (P<0,001), a lipoproteína de baixa densidade (LDL) em 6,4 % e os triglicérides em 8,3 % (P<0,05) e aumentaram as concentrações de campesterol e sitosterol no plasma em 18,9% e 21,6%, respectivamente. Não houve alteração nos valores de lipoproteína de alta densidade (HDL). Com relação aos biomarcadores de aterosclerose, os fitoesteróis provocaram redução apenas na endotelina-1 em 11 % (P<0,05). Esta ação foi independente da redução do LDL-C. Não houve alteração no RNAm para 3-hydroxy-3-methylglutaryl coenzyme A redutase e receptor de LDL. Conclusão: Os fitoesteróis são eficientes na redução da concentração plasmática do colesterol total, triglicérides, LDL-C e da endotelina-1, sendo esta última independente da redução do colesterol / Background: Phytosterols are recommended in the treatment of moderate hypercholesterolemia. Although their mechanisms of action on cholesterol reduction has been exhaustively studied, other activities, such as their effects on inflammatory arterial markers and on endothelial function, have not yet been fully investigated. Objective: To evaluate the efficacy of phytosterols added to soy milk on the reduction of plasma lipids, on biomarkers involved in the pathogenesis of atherosclerosis and on transcriptional changes in 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase and low density lipoprotein receptor in moderately hypercholesterolemic individuals. Design: Moderately hypercholesterolemic patients (n=38, mean age 58 y) were initially followed over a 3-wk baseline period to evaluate their adherence to the program and their tolerance to the added milk. Patients received soy milk (400 mL/d) or soy milk + phytosterol (1.6 g/d) for 2 periods of 4-wk each. The study was randomized, blinded and crossed. Results: Body weight was maintained during the study. Phytosterol treatment reduced the total cholesterol concentration 5.5 % (P < 0.001), low density lipoprotein (LDL) 6.4 % and triglycerides 8.3 % (P<0.05), without modifying high density lipoprotein (HDL). Phytosterol reduced plasma endothelin-1 by 11 % (P<0.05), independently of LDL-C lowering activity. No effects on LDL receptor or on HMGCoA reductase mRNA expression in mononuclear blood cells were found. Sitosterol and campesterol plasma concentrations increased with phytosterol consumption by 18.9% and 21.6%, respectively. Conclusions: Phytosterol effectively lowered plasma total cholesterol, LDL-C, triglycerides and endothelin-1 concentration. The reduction in endothelin-1 concentration was independent of the decrease in the LDL-C concentration

Pediatric obesity has reached epidemic proportions. Reducing obesity among children is expected to lower their likelihood of being obese as adults and, therefore, lower their cardiovascular and metabolic risk profile in adulthood including hypertension, dyslipidemia, type II diabetes, heart disease, and stroke. Pediatric obesity among ages 2–19 is defined as a body mass index (BMI) greater than or equal to the 95th percentile for age and gender as defined according to the CDC BMI-for-age growth charts. Risk factors for obesity are present as early as birth, suggesting exposures at different stages of the life cycle are important to study. The primary objective of this thesis was to evaluate exposures throughout childhood and evaluate their association with both weight and metabolic status. Study 1 examined the relationship between physical activity and metabolic syndrome in overweight and obese youth ages 12–19. We found that even modest amounts of moderate to vigorous physical activity were associated with a reduction in risk of metabolic syndrome, with time spent in vigorous physical activity driving the association. Study 2 explored the relationship between environmental tobacco smoke (ETS) exposure and childhood overweight and obesity in 3–6 year old children. We observed that ETS has a positive association with risk of overweight/obesity, with a dose-response effect observed. Study 3 examined the relationship between maternal antibiotic use during pregnancy and infant birthweight. We did not observe any association between maternal antibiotic use and birthweight or BW/GA-z (birthweight adjusted for gestational age z-score), but we did observe a reduction in risk of SGA (small for gestational age) for infants exposed to antibiotics during gestation. This association was most evident among third trimester users. / 2019-06-09T00:00:00Z

Os efeitos deletérios do excesso de peso sobre a saúde dos cães são bastante citados na literatura, mas pouco investigados. O termo hiperlipidemia refere-se ao aumento da concentração de lipídeos (colesterol, triglicérides ou ambos) séricos. As desordens lipídicas são relativamente comuns nos cães e estas condições podem ocorrer como resultado de um defeito primário no metabolismo de lipoproteínas ou como conseqüência de doença sistêmica subjacente. O objetivo deste estudo foi avaliar a frequência de animais obesos que apresentam alterações nas concentrações de lipídios séricos e analisar a possível correspondência desta condição com grau de obesidade, sexo, idade e castração. Foram incluídos 30 cães obesos com escore de condição corporal (ECC) igual ou superior a 8 (em escala de um a nove, com nove representando obesidade acentuada) e um grupo controle de dez animais com ECC igual a cinco. Nos animais com ECC 9 (n=21), foi encontrada freqüência de 52,4% (n=11) de cães com hipercolesterolemia e 33,3% (n=7) com hipertrigliceridemia. Nos animais com EEC 8 (n=9) foi encontrada freqüência de 22,2% (n=2) de hipercolesterolemia e de 33,3% (n=3) de hipertrigliceridemia. Estas alterações também apresentaram correspondência com o sexo feminino, faixa etária entre quatro e sete anos e a castração. Todavia, a elevação destes metabólitos foi moderada e não se situou em faixa de reconhecido risco à saúde / The harmful effects of obesity on dog health are quite mentioned in the literature, but little investigated. The term hyperlipidemia refers to the increase of lipid and/or fat concentration (cholesterol, triglycerides or both) in serum. These disorders are relatively common in dogs and may happen as a result of a primary defect in metabolism of lipoproteins or as a consequence of a subjacent systemic disease. The aim of this study was to evaluate the frequency of obese dogs that present alterations on cholesterol and triglycerides serum concentration, and to study the correlation of these disorders with obesity degree, sex, age and castration. Thirty obese dogs with body condition score (BCS) equal or superior to 8 (on a scale between one to nine, and nine representing severe obesity) and a control group of ten dogs with BCS of 5 were included. Animals with BCS of 9 (n=21 dogs) presented a frequency of 52.4% (n=11 dogs) of hypercholesterolemia and 33.3% (n=7) of hypertriglyceridemia. Dogs with BCS of 8 (n=9) presented a frequency of 22,2% (n=2) of hypercholesterolemia and 33,3% (n=3) of hypertriglyceridemia. These alterations also presented correspondence with female sex, age between 4 and 7 years and castration. However, the cholesterol and triglycerides increases were moderate, and not remained within the range of recognized health risk

An increased risk for coronary heart disease among shift workers is earlier shown in the epidemiological literature. The aim of this thesis has been to penetrate metabolic disturbances and obesity among shift workers compared to day workers, and to compare if there are differences in total mortality or cause specific mortality of coronary heart disease (CHD), diabetes or ischaemic stroke in between the two groups. In an intervention study on female nurses (N=11), on night schedules in Umeå hospital, the highest peak value of glucose and insulin after meal ingestion was seen in the late evening (23:30). The post-prandial area under curve (AUC) of glucose and insulin was correspondingly largest after meal ingestion the same clock hour compared to meal ingestion other clock times. In two different cross-sectional studies Västerbotten Inventory Study (VIP) (N= 27,485) and in a subset of Work, Lipids and Fibrinogen Study (WOLF) (N= 1,324) metabolic differences in between shift and day workers has been evaluated. In both studies have obesity, high triglycerides and low HDL-cholesterol been more prevalent among the shift-working group compared to the day-working group. After adjustments for age and socio-economic factors in the VIP-study obesity and high triglycerides remained as risk factors in shift workers in both men and women. After directly age standardisation, a clustering effect, simultaneously, of two or more metabolic risk factors (obesity, hypertension, and high triglycerides) was seen in both genders among the shift workers compared to the day workers. Correspondingly, in the Wolf study low HDL-cholesterol and high triglycerides remained as significant risk factors after adjustments of confounders as age, socio-economic group, physical activity, current smoking, low social support and high job strain. In a cohort study from one company (MoDo) with two plants in the pulp and paper industry 2,354 male shift workers and 3,088 male day workers were followed from January 1, 1952 to December 31, 2001 regarding total and cause specific mortality due to CHD, diabetes and ischaemic stroke. Groups of workers defined by different duration of shift exposure were compared with day workers by calculating standardised relative rates (SRR). No increased risk of total mortality was seen among shift workers compared to day workers. Higher duration of shift work was associated with increased risk for CHD, and shift workers with 30 years or more had the highest risk. Diabetes was more common with increasing number of shift year exposure. Compared to day workers shift workers had also an increased risk to die because of ischaemic stroke, with the highest relative difference in the least shift exposed group (&lt; 5 years).

<p>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 &ordm / C 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 &ordm / C, 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 &ordm / C, 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 &ordm / C. 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 &deg / 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 &ordm / C. 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.</p>