Glucagon-like peptide-1 (GLP-1) is an anti-diabetic intestinal L cell hormone. The monounsaturated fatty acid, oleic acid (OA), is an effective GLP-1 secretagogue that crosses the cell membrane by an unknown mechanism. Immunoblotting demonstrated the presence of fatty acid transport proteins (CD36 and FATP1, 3 and 4) in the murine GLUTag L cell model. The cells demonstrated specific 3H-OA uptake, which was dose-dependently inhibited by unlabeled-OA. Phloretin and SSO, inhibitors of carrier-mediated transport and CD36, respectively, also significantly decreased 3H-OA uptake, as did knocking down FATP4 by transfection of siRNA. OA dose-dependently increased GLP-1 secretion in GLUTag cells, while phloretin and FATP4 knockdown, but not SSO, decreased this response. OA injected directly into the ileum of wild-type mice increased plasma GLP-1 levels; in contrast, preliminary findings suggest decreased GLP-1 levels in FATP4 null mice at 60 min. Collectively, these findings indicate a role for FATP4 in OA-induced GLP-1 secretion.

Purpose: Evidence suggests that olive oil consumption is associated with a decreased prevalence of cardiovascular disease and certain cancers. The purpose of this study was to assess the intake and knowledge of olive oil and other lipids in a collegiate population. Methods: Using an IRB-approved protocol, volunteered college students (N=56) from the college of Health and Human Sciences at Georgia State University completed a questionnaire on lipid and knowledge and eating behavior. Results were assessed to determine if students were able to accurately answer questions on the contents of different lipids, and also to determine the consumption behaviors of different lipids. Statistical comparisons were made between undergraduate and graduate students, and between students in different academic majors (nutrition, nursing, respiratory therapy, social work, criminal justice, and other). Results: It was hypothesized that eating behaviors would overemphasize unhealthy lipids. Lipids assessed included: olive oil, butter, canola oil, peanut oil, corn oil, margarine, sunflower oil, and soybean oil. There were no statistically significant differences between the ratios of consumed lipids labeled as ‘good’, and lipids labeled as ‘bad’. There were also no statistically significant differences in the presence of ‘good’ to ‘bad’ lipids in the subjects’ kitchens. Therefore, the results of this study were not able to disprove the null hypothesis. Nevertheless, using a Likert scale response scheme, there was a difference (p=0.041) between academic majors in the consumption of canola oil (an oil high in monounsaturated fatty acid), with Nursing majors reporting the highest consumption (X=3.73; SD=1.61) and Respiratory Therapy majors reporting the lowest consumption (X=1.89; SD=1.53). There was no statistically significant difference between graduate and undergraduate students in the presence of lipids in the kitchen. It was hypothesized that subject knowledge of lipid constituents would be poor. The majority of subjects either failed to respond correctly to the constituents of different lipids or reported that they did not know. Based on this result, the study is able to reject the lipid knowledge null hypothesis. There were clear differences in subgroup knowledge of commonly consumed lipids. Most notably, 100% of nutrition students responded correctly to the constituents of olive oil. Conclusions: This study focused on a group of college students in the College of Health and Human Sciences. One might assume that such a population would be sensitive and knowledgeable about key dietary factors that may influence disease risk. Nevertheless, these findings indicate that, except for isolated exceptions, the eating behaviors and lipid knowledge of these students in not at a level that could be considered health promoting. This suggests that, even with students in the health sciences, personal health classes are likely to be beneficial in reducing disease prevalence.

There is a growing interest in documenting the effect of diet on the ability to convert saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA) by modulating expression of the SCD gene. We propose that if cattle were raised to a constant body weight, their MUFA:SFA ratio will be the same regardless of being calf-fed (CF) or yearling-fed (YF). Twenty-four Angus cattle were acquired for this study. Cattle were slaughtered at weaning at 8 mo of age (SFCF, n=4), eight steers were assigned to the CF group and slaughtered at 12 mo of age (MFCF, n=4) and 16 mo of age (LFCF, n=4). Twelve cattle were assigned to the YF group and slaughtered at 12 mo of age (SFYF, n=4) 16 mo of age (MFYF, n=4) and market weight of 525 kg (LFYF, n=4). Cattle were then statistically analyzed based on time on high energy diet. Fatty acids from digesta, plasma, liver, L. dorsi, and s.c. and i.m. adipose tissue were all analyzed by FAME. In s.c. 18:1 and 16:1 were greatest in LFCF (41.27% and 5.58%, respectively, P = 0.05), and 18:0 and 16:0 did not differ between groups (P > 0.10). MUFA:SFA ratios of s.c. tended to be higher in LFCF animals (1.26) vs. LFYF (1.06, P = 0.10). However, there was no difference seen when comparing CF to YF animals (P = 0.26). MUFA:SFA ratio was higher in i.m. (P = 0.03) and also increased with age (P < .01). A trained sensory panel saw no significant differences between palatability of flavor characteristics of cooked steaks from LFCF, MFYF, or LFYF (P > 0.05). We showed increased SCD gene expression in the LFYF (248.41 to 1528.69 SCD/GAPDH, P = 0.01). Expression was higher in YF (P = 0.04), but their initial deposits of SFA, combined with the lack of SCD expression while on pastures, prevented the MUFA:SFA ratio from increasing at a rate fast enough to change the final ratios in the animal.

Oleic acid (18:1) is one of the important monounsaturated fatty acids, which is synthesized upon desaturation of stearic acid and this reaction is catalyzed by the SSI2 encoded stearoyl-acyl-carrier-protein-desaturase. A mutation in SSI2 leads to constitutive activation of salicylic acid (SA)-mediated defense responses. Consequently, these plants accumulate high levels of SA and show enhanced resistance to bacterial and oomycete pathogens. Replenishing 18:1 levels in ssi2 plants, via a second site mutation in GLY1 encoded glycerol-3-phosphate (G3P) dehydrogenase, suppresses all the ssi2-triggered phenotypes. Study of mechanism(s) underlying gly1-mediated suppression of ssi2 phenotypes showed that 18:1 levels are regulated via acylation with G3P and a balance between G3P and 18:1 is critical for the regulation of defense signaling pathways. To establish a role for 18:1 and G3P during host defense, interaction between Colletotrichum higginsianum and Arabidopsis was studied. Resistance to C. higginsianum correlated with host G3P levels. The gly1 plants showed increased susceptibility while act1 plants, defective in utilization of G3P, showed enhanced resistance. Plant overexpessing GLY1 showed enhanced resistance in both wild type as well as camalexin deficient backgrounds. Together, these results suggested that G3P conferred resistance acted downstream or independent of camalexin. Exogenous application of glycerol lowered 18:1 levels and produced ssi2-like phenotypes in wild-type plants. Furthermore, glycerol application or the ssi2 mutation produced similar phenotypes in fatty acid desaturation mutants and mutants defective in SA/resistance gene signaling. Expression studies showed that ssi2 phenotypes were likely due to increased expression of resistance genes. Epistatic analysis suggested that certain components of SA pathway had redundant function and were required for 18:1-regulated signaling.

The coalburg seam coal is an example of difficult to float bituminous coal. Laboratory tests conducted on coalburg flotation feed sample revealed recovery values around 28% with 15% product ash when using fuel oil as collector under natural pH conditions. A detailed study showed that increasing pH from natural value of 5.6 to 7.5 provided a significant improvement in recovery of approximately 32 absolute percentage points. The improvement is believed to be result of the release of humic acids from the surface and the dispersion of clay particles thereby leaving a more hydrophobic surface. Based on the tests conducted with various commercially available collectors, oleic acid was selected as a model collector for oxidized coals. Conventional flotation tests found an increase in combustible recovery of 10 absolute percentage points above the pH improvement using 4:1 blend of fuel oil and oleic acid. The problem of higher ash in conventional cell product due to entrainment was minimized by the use of wash water in a flotation column. A flotation concentrate containing less than 7.5% ash was produced while recovering around 75% of the combustible material. Further testing using fatty acids-fuel oil blend also showed evidence of a near 200% increase in flotation rate.

Le faible coût du glycérol sur le marché a conduit à des études approfondies sur la conversion du glycérol en dérivés à valeur ajoutée. Ce travail se concentre sur l'estérification catalytique du glycérol, avec l'acide oléique, réaction d’intérêt industriel en raison de la grande valeur commerciale des produits obtenus. Dans ce travail, un nouveau catalyseur acide hétérogène présentant une surface hydrophobe a été développé sur le support ZrO2-SiO2 car un catalyseur acide solide tolérant à l'eau est essentiel pour les réactions d'estérification en milieu biphasique produisant de l'eau. Le catalyseur synthétisé (ZrO2-SiO2-Me&Et-PhSO3H) a été préparé par silication et modification de surface en utilisant du triméthoxyméthylsilane (TMMS) et du 2-(4- chlorosulfonylphényl) éthyltriméthoxysilane. La morphologie de surface, les propriétés physicochimiques et texturales, l'acidité et l'hydrophobicité ont été caractérisées. Le mécanisme de modification de la surface du catalyseur est proposé en fonction des résultats de caractérisation complets. Une nouvelle technique pour contrôler le niveau d'acidité et d'hydrophobicité du catalyseur conçu est décrite dans ce travail. L'acidité et l'hydrophobicité du catalyseur ont été réglées en contrôlant la quantité d'agents de modification de surface. Il a pu être montré que l'hydrophobicité du catalyseur était diminuée à mesure que son acidité augmentait. Le catalyseur ZrO2-SiO2-Me & Et-PhSO3H_70 avec 70% molaire de TMMS et 0,62 mmol/g d'acidité est le catalyseur optimal pour l'estérification du glycérol avec l'acide oléique. Enoutre, le rôle de l'hydrophobicité dans la réaction catalytique a été étudié ici. Ce travail a montré qu'à acidité constante du catalyseur, le catalyseur le plus hydrophobe présentait un meilleur rendement. La conversion en utilisant le catalyseur préparé (ZrO2-SiO2-Me et EtPhSO3H_70) est de 88,2% avec une sélectivité en monooléate de glycérol de 53,5% et une sélectivité en dioléate de glycérol de 40,0% (sélectivité combinée de 94% en monooléate et dioléate de glycérol) pour un rapport équimolaire d'acide oléique/glycérol, une température de réaction de 160°C, une concentration massique du catalyseur de 5% par rapport à la masse d’acide oléique introduit, en conditions de réaction sans solvant et avec un temps de réaction de 8 h. Ce travail révèle que l'hydrophobicité et le volume des pores du catalyseur conçu affectent significativement la sélectivité en produit. De plus, les performances du catalyseur hydrophobe ZrO2-SiO2-Me&Et- PhSO3H_70, ont été comparées à celles de la zircone sulfatée (SO42-/ZrO2) et des catalyseurs commerciaux (Amberlyst 15 et Aquivion). Les résultats de corrélation ont montré que le volume moyen des pores (taille des pores) influençait la sélectivité du produit lorsque le catalyseur ZrO2- SiO2-Me&Et-PhSO3H_70 était comparé à trois catalyseurs SO42-/ZrO2 développés à partir de différents précurseurs de zirconium. Ainsi, le catalyseur à volume de pores le plus élevé est favorable à la production de dioléate de glycérol dans des conditions réactionnelles identiques. On peut conclure que le volume et la taille des pores peuvent être utilisés pour contrôler la sélectivité en produit. En outre, cette étude a également révélé que la propriété d'hydrophobicité améliorait la vitesse de réaction initiale. / The low market value of glycerol has led to extensive investigations on glycerol conversion to value-added derivatives. This work focuses on industrially important catalytic esterification of glycerol with oleic acid due to the high commercial value of the resulting products. In this work, a novel heterogeneous acid catalyst featuring hydrophobic surface was developed on ZrO2-SiO2 support as water tolerant solid acid catalyst is vital for biphasic esterification reactions producing water. The synthesized catalyst (ZrO2-SiO2-Me&Et-PhSO3H) was prepared through silication and surface modification using trimethoxymethylsilane (TMMS) and 2-(4-chlorosulfonylphenyl) ethyltrimethoxysilane. The surface morphology, physiochemical and textural properties, acidity and hydrophobicity were characterized. The mechanism of the catalyst surface modification is thereof proposed according to comprehensive characterization results. A novel technique to control acidity and hydrophobicity level of the designed catalyst is disclosed in this work. The acidity and hydrophobicity of the catalyst were tuned by controlling the amount of surface modification agents. It was found that the hydrophobicity of the catalyst decreased as its acidity increased. ZrO2-SiO2-Me&Et-PhSO3H_70 catalyst with 70 mol% of TMMS and 0.62 mmol/g acidity is the optimal catalyst for glycerol esterification with oleic acid. Furthermore, the role of hydrophobicity in catalytic reaction was investigated herein. It was found that at constant catalyst acidity, the more hydrophobic catalyst showed better yield. The conversion using the designed catalyst (ZrO2-SiO2-Me&EtPhSO3H_70) is 88.2% with 53.5% glycerol monooleate selectivity and 40.0% glycerol dioleate selectivity (combined 94% selectivity of glycerol monooleate and dioleate) at equimolar oleic acid-to-glycerol ratio, 160 oC, reaction temperature, 5 wt% catalyst concentration with respect to weight of oleic acid, solvent-less reaction conditions and 8 h reaction time. This work reveals that the hydrophobicity and the pore volume of the designed catalyst significantly affect the product selectivity. In addition, the performance of the hydrophobic designed ZrO2-SiO2-Me&Et-PhSO3H_70 catalyst was used to benchmark with catalytic activity of sulfated zirconia (SO42-/ZrO2) and commercial catalysts (Amberlyst 15 and Aquivion). The correlation results showed that the average pore volume (pore size) influenced the product selectivity when ZrO2-SiO2-Me&Et-PhSO3H_70 catalyst was compared to three SO42-/ZrO2 catalysts that were developed from different zirconium precursors. Whereby, the higher pore volume catalyst is favourable to glycerol dioleate production at identical reaction conditions. It can be concluded that pore volume and size can be used to control the product selectivity. In addition, this study also revealed that hydrophobicity characteristic facilitated initial reaction rate effectively.

Este trabalho investiga a obtenção de nanopartículas (NP) de óxido de ferro por coprecipitação, sua estabilização com surfactantes e caracterização quanto à morfologia e comportamento magnético. Atualmente, as NP estão sendo amplamente utilizadas para aplicações biomédicas, tais como contraste em imagens médicas e sistema de distribuição de drogas. Na síntese das NP foram investigados, parâmetros como a temperatura da reação, o pH da solução e a velocidade de agitação. O estudo da estabilidade comparou dois diferentes surfactantes: o ácido oleico (AO) e o polietileno glicol (PEG). As NP obtidas foram caracterizadas por difração de raios X (DRX), e quanto à sua morfologia por microscopia eletrônica por varredura (MEV) e microscopia eletrônica de transmissão (MET), a qual também proporcionou uma distribuição de tamanho de partículas, com variação entre 5 nm e 10,23 nm. A interação entre o óxido de ferro e seus revestimentos foi caracterizada por espectrocopia no infravermelho (FTIR) e espectrocopia Raman. O comportamento magnético das NP foi caracterizado por magnetometria de gradiente de força alternada (AGFM) e espectroscopia Mössbauer. Os resultados revelaram que as NP de óxido de ferro são tipicamente constituídas por magnetita ( ) revestida com AO e PEG e com um tamanho médio de cristalito entre 4,6 e 19,2 nm, calculado através da equação de Scherrer. O AGFM mostrou que as propriedades magnéticas das partículas foram mais eficientes para as NP com revestimento, do que com as NP sem revestimento, e o valor de magnetização de saturação (M) para a revestida com PEG foi maior quando comparado com a revestida com AO. A espectroscopia Mössbauer foi utilizada para confirmação do óxido de ferro como , para estimar tamanho de partícula quando os espectros são medidos a baixa temperatura e para análise do comportamento superparamagnético das partículas. / This work investigates the obtained nanoparticles (NP) iron oxide by coprecipitation stabilization with surfactants and characterize the morphology and magnetic behavior. Currently, the NP are being widely used for biomedical applications such as contrast in medical imaging and drug delivery system. In the synthesis of NP were investigated parameters such as the reaction temperature, the pH and stirring speed. The stability study compared two different surfactants: oleic acid (OA) and polyethylene glycol (PEG). The NP were characterized by X-ray diffraction (XRD), and morphologically by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which also provided a distribution of particle size, ranging from 5 nm and 10.23 nm. The interaction between the iron oxide and their coatings was characterized by infrared spectroscopy (FTIR) and Raman spectroscopy. The magnetic behavior of NP was characterized by magnetometry alternating gradient force (AGFM) and Mössbauer spectroscopy. The results show that the NP iron oxide are typically comprised of magnetite ( ) coated with PEG and AO and a crystallite size between 4.6 and 19.2 nm calculated by the Scherrer equation. The AGFM showed that the magnetic properties of the particles were more efficient for the NP uncoated than to NP coated, and the value of saturation magnetization (M) to coated with PEG was higher when compared to coated AO. Mössbauer spectroscopy was used to confirm the iron oxide as , to estimate the size of particle where the spectra are measured at low temperature and to analyze the behavior of superparamagnetic particles.

Biodiesel é um biocombustível que consiste na mistura de ésteres monoalquílicos de ácidos graxos de cadeia longa. O processo usual de produção deste combustível é a transesterificação de óleos vegetais com álcoois de cadeia curta. Nesse processo, a matéria prima deve conter baixo conteúdo de ácido graxos livres ( &#8804; 1%) e água (&#8804; 0,5%). Como alternativa ao processo de transesterificação, destaca-se o emprego de matérias-primas de baixo custo, com elevado teor de ácidos graxos livres, para a síntese de ésteres alquílicos através de reações de esterificação. As reações de produção do biodiesel podem ser catalisadas por via química (ácida e básica) ou enzimática. Na catálise enzimática, os biocatalisadores empregados são as lipases, que catalisam a hidrólise e síntese de ésteres e podem ser obtidas a partir de microrganismos, plantas ou tecido animal, sendo as de origem microbiana as mais utilizadas. O objetivo principal deste trabalho foi avaliar o potencial da lipase de Yarrowia lipolytica, uma levedura não convencional, na síntese de ésteres do ácido oleico visando à obtenção de ésteres alquílicos (biodiesel). Foram estudados os efeitos da temperatura (25, 30, 35, 40, 50 e 60oC), do teor enzimático (5, 10, 20, 30 e 40% v/v) e do tipo de álcool (metanol, etanol, n-propanol e n-butanol ) nas reações de esterificação do ácido oleico empregando o extrato enzimático líquido produzido por Yarrowia lipolytica. Os resultados obtidos mostraram que as reações conduzidas a 30oC e com 10% v/v do extrato enzimático apresentaram maior taxa inicial de reação. Também foi avaliada a utilização do extrato enzimático liofilizado (5% m/v) e do PES (produto enzimático sólido) (5% m/v) de Yarrowia lipolytica na reação de esterificação do ácido oleico com n-butanol a 30oC. O maior consumo de ácido oleico ocorreu na reação conduzida com o PES. O efeito da temperatura (25, 30, 35, 40 e 50oC) na síntese de oleato de butila foi, então, investigado nas reações empregando PES como biocatalisador e a maior conversão de ácido oleico foi verificada na temperatura de 40oC / Biodiesel is a biofuel which consists in a mix of monoalkylesters from long chain fatty acids. The usual method of producing this fuel is transesterification of vegetable oils with lower alcohols. In this process, the raw material should have a low content of free fatty acid (&#8804; 1%) and water(&#8804; 0.5%). As an alternative to the transesterification process stands out the use of low cost raw materials with high content of free fatty acids for the synthesis of alkyl esters through esterification reactions. Reactions for biodiesel production can be catalyzed chemically (acid and basic) or enzymatic. In enzymatic catalysis biocatalysts employed are lipases which are enzymes that catalyze hydrolysis and ester synthesis and can be obtained from microorganisms, plants and animal tissue and the most widely used is from microbial origin. The main objective of this study was to evaluate the potential of Yarrowia lipolyticas lipase a non-conventional yeast on the synthesis of esters of oleic acid in order to obtain alkyl esters (biodiesel). Effects of temperature (25, 30, 35, 40, 50 and 60oC) enzyme content (5, 10, 20, 30 and 40% v/v) and type of alcohol (methanol, ethanol, n-propanol and n-butanol) were studied in the esterification reactions of oleic acid employing enzymatic liquid produced by Yarrowia lipolytica. The results demonstrated that reactions conducted at 30oC and with 10% v/v of the enzyme extract showed higher initial reaction rate and higher conversion of oleic acid for all alcohols studied. Use of lyophilized enzyme extract (5%w/v) and SEP(solid enzymatic product) (5% w/v) from Yarrowia lipolytica was also evaluated in the esterification reaction of oleic acid with n-butanol at 30oC. The higher consumption of oleic acid has occurred in the reaction conducted with SEP. The effect of temperature (25, 30, 35, 40 and 50oC) in the synthesis of butyloleate was then investigated in reactions employing SEP as biocatalyst, and the higher conversion of oleic acid was observed at 40oC

A obesidade é atualmente um dos problemas públicos de saúde mais visível e negligenciado. Ainda, essa condição pode causar sérios problemas de saúde como doenças cardiovasculares, diabetes, hipertensão arterial e diversos problemas fisiológicos. Dietas alimentares e/ou o uso de fármacos tem demonstrado pouca eficiência (e grandes efeitos colaterais) em reduzir a incidência de sobrepeso e obesidade no mundo. Dessa forma outras estratégias são requeridas para auxiliar no controle desta epidemia global. Nesse contexto, alguns ácidos graxos específicos podem desempenhar um importante papel na regulação da expressão de genes que possuem a habilidade de modular metabolismo. O ácido linoléico conjugado (CLA, 18:2) e o ácido oléico (18:1) tem sido descritos com propriedades anti-obesidade: a respeito de CLA, são bem conhecidos os seus efeitos adipotróficos; quanto ao oléico, são bem conhecidos os seus efeitos anti-diabetes; outros efeitos desses ácidos graxos sobre o metabolismo corporal são desconhecidos ou controversos. Dessa forma, o objetivo deste trabalho foi avaliar os efeitos da suplementação da dieta de camundongos (C57bl6) com esses dois ácidos graxos, individualmente ou em conjunto, na modulação do metabolismo corporal e mitocondrial como uma possível estratégia de combate à obesidade. Foram analisados parâmetros bioquímicos, moleculares, fisiológicos, morfológicos e funcionais. Nossos resultados demonstram que o ácido graxo indutor de aumento do gasto energético corporal e mitocondrial hepático é o CLA e não o oléico; quando suplementados em conjunto, os efeitos metabólicos do CLA se sobrepõem aos do oléico, mantendo esses metabolismos elevados. O aumento de metabolismo mitocondrial está relacionado ao aumento de expressão/atividade de proteínas desacopladoras, as quais parecem ser controladas por espécies reativas de O2 mitocondriais. Demonstramos também que no tecido adiposo branco o ácido oléico não exerce efeitos atróficos como o CLA, os quais estão relacionados a inibição da expressão de PPAR1. Por outro lado, verificamos que a suplementação conjunta com ácido oléico previne efeitos adversos da suplementação da dieta com CLA, como a hipertrofia hepática e resistência a insulina. Concluímos dessa forma que a suplementação da dieta com CLA aumenta o metabolismo corporal e mitocondrial; a suplementação com ácido oléico em conjunto não potencializa os efeitos do CLA, porém previne seus efeitos adversos como a hipertrofia hepática e resistência a insulina. Em conjunto esses ácidos graxos constituem uma boa estratégia alimentar contra o ganho de peso corporal. / Obesity is one of the major public health problems. This condition can leads to the development of other complications such as cardiovascular disease, diabetes and hypertension. Diet and/or drug treatments have shown low efficiency (and major side effects) in reducing the incidence of overweight and obesity in worldwide. On the other hand, some specific fatty acids may play an important role regulating the expression of genes that modulate the metabolism. Conjugated linoleic acid (CLA, 18:2) and oleic acid (18:1) have been known for their anti-obesity properties: CLA is well described inducer of atrophy in adipose tissue, while oleic acid is known by its anti-diabetic effects; other effects of these fatty acids on body metabolism are unknown or controversial. Therefore, the aim of this study was to evaluate the effects of a murine diet supplemented with CLA and oleic acid, individually or together, in the modulation of body and mitochondrial metabolism. Biochemical, molecular, physiological, morphological and functional parameters were analyzed in mice. Our results show that CLA, and not oleic acid, is the fatty acid inductor of increase in body metabolism and liver mitochondrial energy expenditure; when supplemented together, the metabolic effects of CLA overlap the oleic effects, maintaining the high metabolism. Increased mitochondrial metabolism is associated with an increased expression/activity of uncoupling proteins, which appear to be controlled by mitochondrial oxygen reactive species. It was also demonstrated that, in white adipose tissue, oleic acid exerts no atrophic effects as compared to CLA, which are related to inhibition of PPAR1 expression. On the other hand, we demonstrated that the supplementation with oleic acid prevents adverse effects of dietary supplementation with CLA, such as liver hypertrophy and insulin resistance in mice. In conclusion, supplementing the murine diet with CLA increases body and mitochondrial metabolism and reduces the adiposity; in addition, supplementation with oleic acid does not potentialize the metabolic effects of CLA, but prevents its adverse effects. Together CLA and oleic in conjunction appears as a good dietary strategy against the excessive weight gain.

Biodiesel é um biocombustível que consiste na mistura de ésteres monoalquílicos de ácidos graxos de cadeia longa. O processo usual de produção deste combustível é a transesterificação de óleos vegetais com álcoois de cadeia curta. Nesse processo, a matéria prima deve conter baixo conteúdo de ácido graxos livres ( &#8804; 1%) e água (&#8804; 0,5%). Como alternativa ao processo de transesterificação, destaca-se o emprego de matérias-primas de baixo custo, com elevado teor de ácidos graxos livres, para a síntese de ésteres alquílicos através de reações de esterificação. As reações de produção do biodiesel podem ser catalisadas por via química (ácida e básica) ou enzimática. Na catálise enzimática, os biocatalisadores empregados são as lipases, que catalisam a hidrólise e síntese de ésteres e podem ser obtidas a partir de microrganismos, plantas ou tecido animal, sendo as de origem microbiana as mais utilizadas. O objetivo principal deste trabalho foi avaliar o potencial da lipase de Yarrowia lipolytica, uma levedura não convencional, na síntese de ésteres do ácido oleico visando à obtenção de ésteres alquílicos (biodiesel). Foram estudados os efeitos da temperatura (25, 30, 35, 40, 50 e 60oC), do teor enzimático (5, 10, 20, 30 e 40% v/v) e do tipo de álcool (metanol, etanol, n-propanol e n-butanol ) nas reações de esterificação do ácido oleico empregando o extrato enzimático líquido produzido por Yarrowia lipolytica. Os resultados obtidos mostraram que as reações conduzidas a 30oC e com 10% v/v do extrato enzimático apresentaram maior taxa inicial de reação. Também foi avaliada a utilização do extrato enzimático liofilizado (5% m/v) e do PES (produto enzimático sólido) (5% m/v) de Yarrowia lipolytica na reação de esterificação do ácido oleico com n-butanol a 30oC. O maior consumo de ácido oleico ocorreu na reação conduzida com o PES. O efeito da temperatura (25, 30, 35, 40 e 50oC) na síntese de oleato de butila foi, então, investigado nas reações empregando PES como biocatalisador e a maior conversão de ácido oleico foi verificada na temperatura de 40oC / Biodiesel is a biofuel which consists in a mix of monoalkylesters from long chain fatty acids. The usual method of producing this fuel is transesterification of vegetable oils with lower alcohols. In this process, the raw material should have a low content of free fatty acid (&#8804; 1%) and water(&#8804; 0.5%). As an alternative to the transesterification process stands out the use of low cost raw materials with high content of free fatty acids for the synthesis of alkyl esters through esterification reactions. Reactions for biodiesel production can be catalyzed chemically (acid and basic) or enzymatic. In enzymatic catalysis biocatalysts employed are lipases which are enzymes that catalyze hydrolysis and ester synthesis and can be obtained from microorganisms, plants and animal tissue and the most widely used is from microbial origin. The main objective of this study was to evaluate the potential of Yarrowia lipolyticas lipase a non-conventional yeast on the synthesis of esters of oleic acid in order to obtain alkyl esters (biodiesel). Effects of temperature (25, 30, 35, 40, 50 and 60oC) enzyme content (5, 10, 20, 30 and 40% v/v) and type of alcohol (methanol, ethanol, n-propanol and n-butanol) were studied in the esterification reactions of oleic acid employing enzymatic liquid produced by Yarrowia lipolytica. The results demonstrated that reactions conducted at 30oC and with 10% v/v of the enzyme extract showed higher initial reaction rate and higher conversion of oleic acid for all alcohols studied. Use of lyophilized enzyme extract (5%w/v) and SEP(solid enzymatic product) (5% w/v) from Yarrowia lipolytica was also evaluated in the esterification reaction of oleic acid with n-butanol at 30oC. The higher consumption of oleic acid has occurred in the reaction conducted with SEP. The effect of temperature (25, 30, 35, 40 and 50oC) in the synthesis of butyloleate was then investigated in reactions employing SEP as biocatalyst, and the higher conversion of oleic acid was observed at 40oC