Regulation of the flow of fatty acids (FA) by futile cycle (TAG/FA cycle) in white adipose tissue (WAT) is an important mechanism of controlling metabolism of FA and therefore its regulation is in the interest of research as a possible therapeutic target in the treatment of obesity and insulin resistance. The study of the murine model suggests that the treatment of the n-3 PUFA with mild caloric restriction (CR) probably induces the TAG/FA cycle mainly in epididymal depot. It also reduces inflammation in WAT and the risk of cardiovascular diseases. We focused on monitoring the gene expression encoding key enzymes of the TAG/FA cycle (PEPCK, ATGL, HSL, DGAT1 and DGAT2) in dorzolumbar (DL), gonadal (GON) and mesenteric (MEZ) depot in a murine model C57BL/6 using qPCR. We were interested in the influence of the composition of fats in the diet, the influence of administration of n-3 PUFA with combination of 10% CR and the difference of gene expression among depots of WAT. The results indicate that the supplementation of high-fat diet with n-3 PUFA contributes mainly to reduction of gene expression for DGAT2 and the combination of n-3 PUFA and CR increases expression of genes influencing the TAG/FA cycle. In MEZ unlike GON and DL fat depot were no significant differences in gene expression, while the different...

Les polymères issus de la biomasse génèrent depuis quelques années un engouement certain puisqu’ils apparaissent comme de potentiels substituts aux polymères issus de l’industrie pétrolière. Parmi ces monomères récemment développés, l’acide succinique bio-sourcé a reçu une attention particulière notamment pour des applications dans le domaine des polyesters tels que le poly(butylène succinate). La présente thèse décrit la synthèse de ce polymère par estérification directe de l’acide succinique et du 1,4-butanediol dans un réacteur pilote de 7.5 L. Les principaux paramètres du procédé tels que l’excès de diol, la température de trans-estérification ainsi que la pureté de l’acide succinique ont été étudiés. Une attention particulière a été portée sur le choix du catalyseur (son type, la quantité utilisée …) afin d’observer son influence sur le procédé ainsi que sur la stabilité du polymère final. Puis différentes stratégies de modification du poly(butylene succinate) ont été testées pour améliorer à la fois sa mise en forme par extrusion gonflage et les propriétés des films obtenus. Dans ce but l’introduction d’agents de branchements, de silices nanométriques ainsi que des comonomères rigides a été étudiée. / Polymers issued from biomass present a growing interest, since they seem to be a suitable alternative to conventional petrochemical polymers. Among the newly developed monomers, bio-based succinic acid received a particular attention for its application in the synthesis of aliphatic polyesters such as poly(butylene succinate). The present thesis reports the synthesis of this polymer via the direct esterification of succinic acid and 1,4-butanediol in a 7.5 L pilote scale reactor. Main process parameters such as the diol exces, the trans-esterification temperature as well as the purity of succinic acid have been studied. In addition a special attention was taken to highlight the influence of the catalyst (its type, quantity ...) on the synthesis and on the stability of the resulting polymer. Then several strategies of modification of poly(butylene succinate) have been studied to improve the processability of the polymer via film extrusion blowing and to enhance the properties of polymer films. To that end the introduction of branching agents, silica nanofillers as well as rigid comonomers have been studied.

Lignin, en av huvudkomponenterna i lignocellulosabiomassa, utgör en stor mängd av sidoströmen från massaindustrin. Lignin är aromatiska makromolekyler som förekommer i rikliga mängder i naturen och uppvisar unika antioxidant-, uv-skyddande, anti-ultravioletta, antikorrosiva och antimikrobiella egenskaper, etc. Ligninbaserade produkter är ännu inte kommersialiserade eftersom de är begränsade av den kemiska heterogeniteten hos lignin som separerats från olika råvaror och producerats i olika industriella processer. Istället förbränns lignin vanligtvis för värme- och elproduktion efter extraktion. Tillvägagångssätt för att bevara värdefulla egenskaper hos lignin och samtidigt övervinna begränsningar har blivit heta ämnen. I detta projekt genomfördes kemiska modifieringar av kraftlignin från olika naturliga råvaror, gran och eukalyptus, där fenolgrupperna ersattes av alkylgrupper med olika kedjelängder (kolnummer 1, 6 och 12). De kemiska strukturerna och de termiska egenskaperna hos kraftlignin studerades med en kombination av analytiska metoder. Egenskaperna hos två typer av tekniska kraftligniner och dess derivat undersöktes även för jämförelse. Resultaten visade att kemiskt modifierat lignin kan vara ett lovande råmaterial för förädlade produkter som till exempel ligninbaserade nanopartiklar. / Lignin, one of the major components in lignocellulose biomass, makes up a large amount of sidestream from the pulp industry. As an abundant feedstock of bio- originated aromatic macromolecules, lignin shows unique antioxidant, UV-protective, anticorrosive, and antimicrobial properties, etc. However, limited by the chemical heterogeneity of lignin separated from different bioresources and industrial procedures as well as its recalcitrance as macromolecules, lignin-based products are not yet commercialized, while lignin is commonly burnt for heat or power generation after extraction. Approaches of preserving valuable properties of lignin meanwhile overcoming limitations have become heated topics. In this project, chemical modifications of kraft lignin from different natural bio-origins, spruce and eucalyptus, were conducted, with alkyl groups of various chain lengths (carbon numbers 1, 6 and 12) substituting the phenolic groups. A combination of analytical methods for characterizing the chemical structures and thermal properties of kraft lignin and chemically modified kraft lignin were studied. Meanwhile, the characteristics of two kinds of technical kraft lignin and their derivatives were investigated for comparison. Results highlighted that chemically modified lignin could be a promising material to serve as a feedstock for value-added products such as lignin-based nanoparticles.

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Batch distillation with chemical reaction when takes place in the same unit is referred to as batch reactive distillation process. The combination reduces the capital and operating costs considerably. Among many different types of batch reactive distillation column configurations, (a) conventional (b) inverted (c) semi-batch columns are considered here. Three reaction schemes such as (a) esterification of methanol (b) esterification of ethanol (c) hydrolysis of methyl lactate are studied here. Four different types of dynamic optimisation problems such as (a) maximum conversion (b) maximum productivity (c) maximum profit and (d) minimum time are formulated in this work. Optimal design and or operation policies are obtained for all the reaction schemes. A detailed rigorous dynamic model consisting of mass, energy balances, chemical reaction and thermodynamic properties is considered for the process. The model was incorporated within the dynamic optimisation problems. Control Vector Parameterisation (CVP) technique was used to convert the dynamic optimisation problem into a nonlinear programming problem which was solved using efficient SQP (Successive Quadratic Programming) method available within the gPROMS (general PROcess Modelling System) software. It is observed that multi-reflux ratio or linear reflux operation always led to better performance in terms of conversion, productivity for all reaction schemes compared to that obtained using single reflux operation. Feed dilution (in the case of ethanol esterification) led to more profit even though productivity was found to be lower. This was due to reduction in feed price because of feed dilution. Semi-batch reactive distillation opertation (for ethanol esterification) led to better conversion compared to conventional batch distillation, however, the total amount of acetic acid (reactant) was greater in semi-batch operation. Optimisation of design and operation (for ethanol esterification) clearly showed that a single cloumn will not lead to profitable operation for all possible product demand profile. Also change in feed and /or product price may lead to adjust the production target to maximise the profitability. In batch distillation, total reflux operation is recommended or observed at the begining of the operation (as is the case for methnaol or ethanol esterification). However, in the case of hydrolysis, total reflux operation was obseved at the end of the operation. This was due to lactic acid (being the heaviest) was withrawn as the final bottom product. / Libyan Petroleum Institute

The synthesis of a number of alkyl esters such as methyl lactate, methyl decanoate, and ethyl benzoate via esterification in a reactive distillation is quite challenging. It is due to the complexity in the thermodynamic behaviour of the chemical species in the reaction mixture in addition to the difficulty of keeping the reactants together in the reaction section. One of the reactants (in these esterification reactions) having the lowest boiling point can separate from the other reactant as the distillation continues. This can result in a significant drop in the reaction conversion in a conventional reactive distillation whether it is a batch or a continuous column. To overcome this challenge, new different types of batch reactive distillation column configurations: (1) integrated conventional (2) semi-batch (3) integrated semi-batch (4) integrated dividing-wall batch distillation columns have been proposed here. Four esterification reaction schemes such as (a) esterification of lactic acid (b) esterification of decanoic acid (c) esterification of benzoic acid (d) esterification of acetic acid are investigated here. A detailed dynamic model based on mass, energy balances, chemical reaction, and rigorous thermodynamic (chemical and physical) properties is considered and incorporated in the optimisation framework within gPROMS (general PROcess Modelling System) software. It is found that for the methyl lactate system, the i-SBD operation outperforms the classical batch operations (CBD or SBD columns) to satisfy the product constraints. While, for the methyl decanoate system, the i-DWCBD operation outperforms all CBD, DWBD and sr-DWBD configurations by achieving the higher reaction conversion and the maximum product purity. For the ethyl benzoate system, the performance of i-CBD column is superior to the CBD process in terms of product quality, and conversion rate of acid. The CBD process is found to be a more attractive in terms of operating time saving, and annual profit improvement compared to the IBD, and MVD processes for the benzyl acetate system. / The Higher Committee for Education Development in Iraq (HCED)

In recent years, water-in-oil Pickering emulsions have been introduced as promising reaction systems for multiphase enzyme catalysis, in particular lipase-catalyzed esterification and transesterification. Here, we for the first time gained insight into the effects that the presence of the proteins exert on the fineness and stability of the emulsion system and thus, the catalytic performance. We demonstrated a distinct, concentration-and enzyme-dependent decrease of droplet sizes in the dispersed phase, accompanied by decreasing stability against coalescence. This was due to a probably quantitative adsorption of lipases at the interphase intercalating the solid particles. Destabilization was reduced slightly at increased particle content and increased volume portion of the dispersed phase, respectively. However, the low tolerable lipase concentrations in the reaction system considerably limited its productivity. Thus, our study points at the enzyme content, or rather enzyme location, in Pickering emulsions being the crucial parameter for optimizing catalytic performance.

Denna studie undersöker effektiviteten hos Calamos nyligen utvecklade elektrolyt. Det är av stor betydelse att förstå hur denna nya elektrolyt, som är fosforfri och baserad på organiska syror, fungerar för att minska beroendet av ändliga resurser och därigenom främja en mer hållbar produktion. Projektets mål var att utveckla en enkel kvantitativ analysmetod för myrsyra, mjölksyra, glykolsyra och oxalsyra i den nya elektrolyten. Tekniken som användes för detektion och kvantifiering var gaskromatografi (GC) kopplad till en flamjoniseringsdetektor (FID). GC är begränsad till analyter som kan överföras till gasfasen utan att brytas ned termiskt. Ett sätt för att öka en förenings flyktighet, termiska stabilitet och kromatografiska beteende är genom en derivatiseringsreaktion. För bättre kromatografisk beteende derivatiserades karboxylsyror före GC-analys med N,O-bis-(trimetylsilyl)trifluoracetamid (BSTFA) som silyleringsreagens och dimetylformamid (DMF) som derivatiseringsmedium. Efter optimering validerades metoden och dess linjäriteten. Metoden har tillämpats för kvantitativ bestämning av karboxylsyror i elektrolyten, följt av lösningsmedelsextraktion med dietyleter. I detta arbete undersöktes även extraktionen av en karboxylsyra genom derivatisering med hjälp av dimetylkarbonat och natriummetoxid, vilket resulterade i bildandet av metylestrar som är relativt opolära och underlättar överföringen av karboxylsyror till den organiska fasen. Resultaten visade att båda teknikerna totalt sett inte verkar lämpliga för analys av karboxylsyror i elektrolyten. Dessutom utsaltningsextraktion av de karboxylsyrorna studerades också med användning av ett system bestående av butanon och ammoniumhydroxid. Resultaten indikerade att denna extraktionsmetod inte var effektiv för karboxylsyrorna. / This study examines the effectiveness of Calamo's newly developed electrolyte. It is of great importance to understand how this new electrolyte, which is phosphorus-free and based on organic acids, works to reduce dependence on finite resources and thereby promote more sustainable production. The project's goal was to develop a simple quantitative analysis method for formic acid, lactic acid, glycolic acid and oxalic acid in the new electrolyte. The technique used for detection and quantification was gas chromatography (GC) coupled to a flame ionization detector (FID). GC is limited to analytes that can be transferred to the gas phase without thermal degradation. One way to increase a compound's volatility, thermal stability and chromatographic behaviour is through a derivatization reaction. For better chromatographic behaviour, carboxylic acids were derivatized prior to GC analysis with N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA) as the silylation reagent and dimethylformamide (DMF) as the derivatization medium. After optimization, the method and its linearity were validated. The method was applied for quantitative determination of carboxylic acids in the electrolyte, followed by solvent extraction with diethyl ether. In this work, the extraction of a carboxylic acid by derivatization with dimethyl carbonate and sodium methoxide was also investigated, which resulted in the formation of methyl esters that are relatively non-polar and facilitate the transfer of carboxylic acids to the organic phase. The results showed that both techniques overall did not seem suitable for the analysis of carboxylic acids in the electrolyte. In addition, salting-out extraction of the carboxylic acids was also studied using a system consisting of butanone and ammonium hydroxide. The results indicated that this extraction method was not effective for the carboxylic acids.

L’obésité s’accompagne de pathologies comme le diabète de type 2 et les maladies cardiovasculaires, liées à des dérégulations métaboliques et endocriniennes du tissu adipeux blanc (TAB). Au cours du vieillissement, la perte de masse musculaire peut être associée à l’obésité et définit le concept d’obésité sarcopénique. Les traitements mis en œuvre pour contrecarrer ces pathologies n’ont qu’un succès très partiel. Il est donc opportun de développer des stratégies alternatives originales qui pourraient aboutir à des thérapeutiques ciblées. Notre équipe étudie les régulations métaboliques du TAB, source majeure de stockage de l’énergie de l’organisme. Les triglycérides stockés sont libérés à jeun grâce à la lipolyse qui libère les acides gras non-estérifiés (AGNE) et le glycérol dans le sang, comme source d’énergie des autres tissus. En plus de la β-oxydation des AGNE, leur ré-estérification partielle intervient pour limiter leur libération lors de la lipolyse. La glycéronéogenèse est nécessaire à la ré-estérification en situation de jeûne. Des études préalables ont montré que l'administration de citrulline (CIT) pendant trois mois à des rats vieillissants induit une diminution d’environ 40% de la masse viscérale du TAB. Cet acide aminé non protéique est un complément alimentaire donné au cours du vieillissement ou à des sportifs pour augmenter la masse musculaire. Nous avons étudié les effets de la CIT sur des cultures d’explants de TAB de rats. Dans la première partie de ce travail, nous montrons que la CIT a un effet direct lipolytique et anti-glycéronéogénique sur les explants des rats qu’ils soient jeunes ou âgés. Cependant, la libération des AGNE du TAB des rats jeunes est limitée par une augmentation de la capacité oxydative du tissu. Avec l’âge, la masse du TAB augmente en parallèle à l’augmentation d’un état pro-inflammatoire. Afin de comprendre l’influence de ces deux paramètres indépendamment de l’âge, nous avons étudié dans la deuxième partie de ce travail, les effets de la CIT sur les explants de TAB de rats jeunes soumis à un régime contrôle (CD) ou hyperlipidique (HFD). Nous observons une augmentation, induite par la CIT, de la lipolyse et de la capacité ß-oxydative du TAB des rats quel que soit le régime, alors que la glycéronéogenèse est diminuée. Toutefois, les AGNE sont sélectivement libérés par le TAB de rats HFD, en relation avec une réduction drastique de leur ré-estérification. Le NO est un médiateur de ces effets. Dans une troisième partie, nous démontrons que la CIT agit directement sur le TAB de rats CD et HFD pour induire l'expression de la protéine découplante, UCP1, en lien avec le « brunissement » potentiel du TAB par cet acide aminé. Ces effets ne sont pas observés au sein du TAB des rats âgés. L’ensemble de nos résultats établit les bases pour de futures investigations visant à élucider les mécanismes par lesquels la CIT réduit la masse adipeuse et ouvre de nouvelles perspectives thérapeutiques pour lutter contre le surpoids et l’obésité sarcopénique. / Obesity is frequently associated with type 2 diabetes and cardiovascular diseases, related to metabolic and endocrine dysregulation of white adipose tissue (WAT). During aging, the loss of muscle mass may be associated with obesity and defines the concept of sarcopenic obesity. Treatments implemented to counteract these conditions showed a very partial success. It is therefore appropriate to develop original alternative strategies that could lead to targeted therapies. Our team studies the metabolic regulation of WAT, the major source of energy storage in the body. Non-esterified fatty acids (NEFA) and glycerol are released in the blood from stored triglycerides through lipolysis and used as a source of energy for other tissues. In addition to their β-oxidation, NEFA are re-esterified in part, a process that limits their release in the blood. Glyceroneogenesis is the pathway necessary to NEFA re-esterification in the fasting state. Previous studies showed that administration of citrulline (CIT) for three months to aging rats induced a decrease of approximately 40% of the visceral WAT mass. This non-protein amino acid is given as a dietary supplement during aging or sports to increase muscle mass. We studied the effects of CIT on explant cultures of rat WAT. In the first part of this work, we show that CIT exerts a direct lipolytic and anti-glyceroneogenic effect on explants from rats whether young or old. However, the release of NEFA from the explants of young rats is limited by an increase in the oxidative capacity of the tissue. During aging, WAT mass augments in parallel to the increase in a pro-inflammatory state. To understand the influence of these two parameters regardless of age, we studied in the second part of this work, the effects of CIT on WAT explants from young rats fed a control (CD) or high fat (HFD) diet. We show an CIT-induced increase in lipolysis and beta-oxidative capacity of WAT from rats whatever the diet, while glyceroneogenesis is reduced. However, NEFA are selectively released from WAT of HFD rats, in connection with a drastic reduction of their re-esterification. NO is a mediator of these effects. In the third part of this work, we show that CIT acts directly on WAT from CD and HFD rats to induce the expression of uncoupling protein, UCP1, in line with the potential "browning" of WAT by this amino acid. These effects were not observed in explants from old rats. Altogether our results establish the basis for future investigations aimed at elucidating the mechanisms by which CIT reduces body fat and open new therapeutic perspectives to fight overweight and sarcopenic obesity.