Biodiesel fuel formulation

O consumo de energia a n��vel mundial aumenta a cada dia, de forma inversa aos recursos f��sseis que decrescem de dia para dia. O sector dos transportes �� o maior consumidor deste recurso. Face ao actual cen��rio urge encontrar uma solu����o renov��vel e sustent��vel que permita n��o s��, diminuir a nossa depend��ncia de combust��veis f��sseis mas fundamentalmente promover a sua substitui����o por energias de fontes renov��veis. O biodiesel apresenta-se na vanguarda das alternativas aos combustiveis derivados do petr��leo, para o sector dos transportes, sendo considerado uma importante op����o a curto prazo, uma vez que o seu pre��o pode ser competitivo com o diesel convencional, e para a sua utiliza����o o motor de combust��o n��o necessita de altera����es. O biodiesel �� uma mistura l��quida, n��o t��xica, biodegrad��vel de ��steres de ��cidos gordos, sem teor de enxofre ou compostos arom��ticos, apresenta boa lubricidade, alto n��mero de cetano, e origina emiss��es gasosas mais limpas. O presente trabalho contribui para um melhor conhecimento da depend��ncia das propriedades termofisicas do biodiesel com a sua composi����o. A publica����o de novos dados permitir�� o desenvolvimento de modelos mais fi��veis na previs��o do comportamento do biodiesel. As propriedades densidade e viscosidade s��o o espelho da composi����o do biodiesel, uma vez que dependem directamente da mat��ria prima que lhe deu origem, mais do que do processo de produ����o. Neste trabalho os dados medidos de densidade e viscosidade de biodiesel foram testados com v��rios modelos e inclusivamente foram propostos novos modelos ajustados para esta fam��lia de compostos. Os dados medidos abrangem uma ampla gama de temperaturas e no caso da densidade tamb��m foram medidos dados a alta press��o de biodiesel e de alguns ��steres metilico puros. Neste trabalho tamb��m s��o apresentados dados experimentais para o equil��brio de fases s��lido-liqu��do de biodiesel e equlibrio de fases l��quidol��quido de alguns sistemas importantes para a produ����o de biodiesel. Ambos os tipos de equil��brio foram descritos por modelos desenvolvidos no nosso laborat��rio. Uma import��ncia especial �� dado aqui a propriedades que dependem do perfil de ��cidos gordos da mat��ria-prima al��m de densidade e viscosidade; o ��ndice de iodo e temperature limite de filtrabalidade s��o aqui avaliados com base nas considera����es das normas. Os ��cidos gordos livres s��o um sub-produto de refina����o de ��leo alimentar, que s��o removidos na desodora����o, no processo de purifica����o do ��leo. A cat��lise enzim��tica �� aqui abordada como alternativa para a convers��o destes ��cidos gordos livres em biodiesel. Estudou-se a capacidade da lipase da Candida antartica (Novozym 435) para promover a esterifica����o de ��cidos gordos livres com metanol ou etanol, utilizando metodologia de superf��cie de resposta com planeamento experimental. Avaliou-se a influ��ncia de diversas vari��veis no rendimento da reac����o.

Economical and operational optimization of CALB immobilization on MP1000 for amidation of olein fatty acids with ethanolamine

Disserta����o de Mestrado , Engenharia Biol��gica, Faculdade de Engenharia de Recursos Naturais, Universidade do Algarve, 2008

Catalytic ethanolysis of soybean oil with immobilized lipase from Candida antarctica and (1)H NMR and GC quantification of the ethyl esters (biodiesel) produced

The catalytic ethanolysis of soybean oil with commercial immobilized lipase type B from Candida antarctica to yield ethyl esters (biodiesel) has been investigated. Transesterification was monitored with respect to the following parameters: quantity of biocatalyst, reaction time, amount of water added and turnover of lipase. The highest yields of biodiesel (87% by (1)H NMR; 82.9% by GC) were obtained after a reaction time of 24 h at 32 degrees C in the presence of lipase equivalent to 5.0% (w/w) of the amount of soybean oil present. The production of ethyl esters by enzymatic ethanolysis was not influenced by the addition of water up to 4.0% (v/v) of the alcohol indicating that it is possible to use hydrated ethanol in the production of biodiesel catalyzed by lipase. The immobilized enzyme showed high stability under moderate reaction conditions and retained its activity after five production cycles. The (1)H NMR methodology elaborated for the quantification of biodiesel in unpurified reaction mixtures showed good correlations between the signal areas of peaks associated with the alpha-methylene groups of the ethyl esters and those of the triacyl-glycerides in residual soybean oil. Monoacylglycerides, diacylglycerides and triglycerides could also be detected and quantified in the crude biodiesel using (1)H NMR spectroscopic and GC-FID chromatographic methods. The biodiesel production by enzymatic catalysis was promising. In this case, was produced a low concentration of glycerol (0.74%) and easily removed by water extraction. (C) 2010 Elsevier B.V. All rights reserved.

Myotoxic phospholipases A2 isolated from Bothrops brazili snake venom and synthetic peptides derived from their C-terminal region: Cytotoxic effect on microorganism and tumor cells

This paper reports the purification and biochemical/pharmacological characterization of two myotoxic phospholipases A2 (PLA2s) from Bothrops brazili venom, a native snake from Brazil. Both myotoxins (MTX-I and II) were purified by a single chromatographic step on a CM-Sepharose ion-exchange column up to a high purity level, showing Mr ��� 14,000 for the monomer and 28,000 Da for the dimer. The N-terminal and internal peptide amino acid sequences showed similarity with other myotoxic PLA2s from snake venoms, MTX-I belonging to Asp49 PLA2 class, enzymatically active, and MTX-II to Lys49 PLA2s, catalytically inactive. Treatment of MTX-I with BPB and EDTA reduced drastically its PLA2 and anticoagulant activities, corroborating the importance of residue His48 and Ca2+ ions for the enzymatic catalysis. Both PLA2s induced myotoxic activity and dose-time dependent edema similar to other isolated snake venom toxins from Bothrops and Crotalus genus. The results also demonstrated that MTXs and cationic synthetic peptides derived from their 115-129 C-terminal region displayed cytotoxic activity on human T-cell leukemia (JURKAT) lines and microbicidal effects against Escherichia coli, Candida albicans and Leishmania sp. Thus, these PLA2 proteins and C-terminal synthetic peptides present multifunctional properties that might be of interest in the development of therapeutic strategies against parasites, bacteria and cancer. �� 2008 Elsevier Inc. All rights reserved.

Isolamento de fungos produtores de lipases catalisadores de rea����es de transesterifica����o para produ����o de biodiesel

P��s-gradua����o em Microbiologia - IBILCE

Produ����o de biodiesel et��lico com uso de lipases extracelulares de fungos termof��licos

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Produ����o de lipases por fungos termof��licos e mesof��licos e uso na produ����o de biodiesel et��lico

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

An��lise dos compostos flavorizantes da cana-de-a����car e otimiza����o da aplica����o de extratos ricos em ��-glicosidases para libera����o de aroma na produ����o de aguardente de cana

P��s-gradua����o em Qu��mica - IBILCE

Aplica����o do fungo termof��lico Thermomyces lanuginosus na s��ntese enzim��tica de ��steres

P��s-gradua����o em Ci��ncias Biol��gicas (Microbiologia Aplicada) - IBRC

Oxida����o de carboidratos via cat��lise met��lica n��o enzim��tica para aplica����o em sensores

This work has main aim of is to propose the synthesis and characterization of nanostructured materials for oxidation of carbohydrates such as glucose, with non-enzymatic catalysis. The proposed pathway of synthesis of metal catalysts is the polyol method and techniques of physical characterization proposals for analysis of prepared catalyst pass through diffraction technique of ray-x (DRX), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy ray-x (EDX). Technical proposals for the electrochemical characterization of the synthesized catalysts are Cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The prospects of this work are compared by the catalytic activity of the sensor designed with non-enzymatic sensors and biosensors also known in the literature

Kinetics and product distribution of p-nitrophenyl phosphate dianion solvolysis in ternary DMSO/alcohol/water mixtures are compatible with metaphosphate formation

The rate of solvolysis of p-nitrophenyl phosphate (PNPP) dianion in DMSO/water strongly decreases by increasing water concentration. Addition of linear alcohols (methanol, propanol, butanol, pentanol, and hexanol) at constant DMSO/water molar ratio produced an even sharper rate decrease. Alkyl phosphate formation, resulting from PNPP solvolysis in ternary DMSO/water/alcohol mixtures, increased with alcohol concentration and was essentially temperature independent. Methanol and hexanol were the poorest nucleophiles under all conditions. Activation energies and enthalpies for solvolysis in ternary mixtures were similar and entropies varied with alcohol concentration. Taken together these results can be best interpreted in terms of a dissociative mechanism with the intervention of metaphosphate. Copyright (C) 2011 John Wiley & Sons, Ltd.

Acqua: solvente elettivo in Organocatalisi e Biocatalisi

Water is a safe, harmless, and environmentally benign solvent. From an eco-sustainable chemistry perspective, the use of water instead of organic solvent is preferred to decrease environmental contamination. Moreover, water has unique physical and chemical properties, such as high dielectric constant and high cohesive energy density compared to most organic solvents. The different interactions between water and substrates, make water an interesting candidate as a solvent or co-solvent from an industrial and laboratory perspective. In this regard, organic reactions in aqueous media are of current interest. In addition, from practical and synthetic standpoints, a great advantage of using water is immediately evident, since it does not require any preliminary drying process. This thesis was found on this aspect of chemical research, with particular attention to the mechanisms which control organo and bio-catalysis outcome. The first part of the study was focused on the aldol reaction. In particular, for the first time it has been analyzed for the first time the stereoselectivity of the condensation reaction between 3-pyridincarbaldehyde and the cyclohexanone, catalyzed by morpholine and 4-tertbutyldimethylsiloxyproline, using water as sole solvent. This interest has resulted in countless works appeared in the literature concerning the use of proline derivatives as effective catalysts in organic aqueous environment. These studies showed good enantio and diastereoselectivities but they did not present an in depth study of the reaction mechanism. The analysis of the products diastereomeric ratios through the Eyring equation allowed to compare the activation parameters (����H��� and ����S���) of the diastereomeric reaction paths, and to compare the different type of catalysis. While morpholine showed constant diasteromeric ratio at all temperatures, the O(TBS)-L-proline, showed a non-linear Eyring diagram, with two linear trends and the presence of an inversion temperature (Tinv) at 53 �� C, which denotes the presence of solvation effects by water. A pH-dependent study allowed to identify two different reaction mechanisms, and in the case of O(TBS)-L-proline, to ensure the formation of an enaminic species, as a keyelement in the stereoselective process. Moreover, it has been studied the possibility of using the 6- aminopenicillanic acid (6-APA) as amino acid-type catalyst for aldol condensation between cyclohexanone and aromatic aldehydes. A detailed analysis of the catalyst regarding its behavior in different organic solvents and pH, allowed to prove its potential as a candidate for green catalysis. Best results were obtained in neat conditions, where 6-APA proved to be an effective catalyst in terms of yields. The catalyst performance in terms of enantio- and diastereo-selectivity, was impaired by the competition between two different catalytic mechanisms: one via imine-enamine mechanism and one via a Bronsted-acid catalysis. The last part of the thesis was dedicated to the enzymatic catalysis, with particular attention to the use of an enzyme belonging to the class of alcohol dehydrogenase, the Horse Liver Alcohol Dehydrogenase (HLADH) which was selected and used in the enantioselective reduction of aldehydes to enantiopure arylpropylic alcohols. This enzyme has showed an excellent responsiveness to this type of aldehydes and a good tolerance toward organic solvents. Moreover, the fast keto-enolic equilibrium of this class of aldehydes that induce the stereocentre racemization, allows the dynamic-kinetic resolution (DKR) to give the enantiopure alcohol. By analyzing the different reaction parameters, especially the pH and the amount of enzyme, and adding a small percentage of organic solvent, it was possible to control all the parameters involved in the reaction. The excellent enatioselectivity of HLADH along with the DKR of arylpropionic aldehydes, allowed to obtain the corresponding alcohols in quantitative yields and with an optical purity ranging from 64% to >99%.

Enantioselective Reactions Promoted by Organocatalytic Species From The Natural Chiral Pool

During the course of my Ph.D. in the laboratories directed by Prof. Alfredo Ricci at the Department of Organic Chemistry ���A. Mangini��� of the University of Bologna, I was involved in the study and the application of a number of organocatalytic systems, all coming from the natural chiral pool. The first part of this thesis will be devoted to new homogeneous organocatalytic reactions promoted by Cinchona alkaloid-based organocatalysts. Quinine based catalysts were found to be a very effective catalyst for Diels-Alder reactions involving 3-vinylindoles. Excellent results in terms of yields and enantioselectivities were achieved, outlining also a remarkable organocatalytic operational mode mimicking enzymatic catalysis. The same reaction with 2-vinylindoles showed a completely different behaviour resulting in an unusual resolution-type process. The asymmetric formal [3+2] cycloaddition with in situ generated N-carbamoyl nitrones using Cinchona-derived quaternary ammonium salts as versatile catalysts under phase transfer conditions, outlines another application in organocatalysis of this class of alkaloids. During the seven months stage in the Prof. Helma Wennemers��� group at the Department of Chemistry of the University of Basel (Switzerland) I have been involved in organocatalysis promoted by oligopeptides. My contribution regarded the 1,4-addition reaction of aldehydes to nitroolefins. In the work performed at the Department of Organic Chemistry ���A. Mangini��� of the University of Bologna, in collaboration with the ���Institut Charles Gerhardt-Montpellier, of Montpellier (France) the possibility of performing for the first time heterogeneous organocatalysis by using a natural polysaccharide biopolymer as the source of chirality was disclosed. With chitosan, derived from deacetylation of chitin, a highly enantioselective heterogeneous organocatalytic aldol reaction could be performed. The use of an eco-friendly medium such as water, the recyclability of the catalytic specie and the renewable nature of the polysaccharide are assets of this new approach in organocatalysis and open interesting perspectives for the use of biopolymers.

Morphologischer und biochemischer Aufbau von Silikatnadeln der Hexactinelliden am Beispiel von Monorhaphis chuni

Schon 1904 beschrieb Schulze den Aufbau von Silikatnadeln des Schwammes Monorhaphis chuni, eines Mitglieds der zweiten Familie von biosilifizierenden Schw��mmen, den Hexactinelliden (Glasschw��mmen). Weitergehende morphologische Untersuchungen und biochemische Analysen insbesondere mit modernen Methoden wurden an Hexactinelliden bisher kaum durchgef��hrt. Ziel der vorliegenden Arbeit bestand deshalb darin, Untersuchungen zur Morphologie, der chemischen Zusammensetzung, der Verteilung und Charakterisierung der beteiligten anorganischen und organischen Komponenten sowie einen molekularbiologischer Nachweis der Existenz von Silicatein in Hexactinelliden durchzuf��hren. F��r diese Untersuchungen wurden zwei Spezies verwendet: Monorhaphis chuni und Crateromorpha meyeri. Mittels Elektronen-Mikrosonden-Technik wurde an Querschnitten der Pfahlnadel von M. chuni die Verteilung der Elemente innerhalb der Nadel untersucht. Am ��u��eren Rand der Nadel (150 ��m) traten im Vergleich zur Nadelmitte pr��gnante Unterschiede in der Konzentration von Kaliumoxid und Natriumoxid auf. Diese Ergebnisse deuten auf das Vorhandensein eines ��hnlichen Transportsystems zur Anreicherung von Silizium/Silikat bei der Nadelbildung hin, wie es bereits in S. domuncula bekannt ist. Mit elektronen- und lichtmikroskopischen Untersuchungen wurden die organischen Substanzen der Silikatnadel nachgewiesen und deren Verteilung innerhalb dieser Nadeln analysiert. In der lamellaren Zone befindet sich, eine s��urelabile organische Netzstruktur, sowie eine, die Silikatschichten durchspannende, s��ulen��hnliche Struktur. Im Axialzylinder zeigt das organische Material eine leicht verzweigte fibrill��re Anordnung. Mit biochemischen Verfahren wurden die organischen Komponenten der Nadeln detaillierter untersucht. Mehrere Proteine mit Molekulargewichten von 17, 24, 27 ,30, 36 und 70 kDa wurden durch gelelektrophoretische Analysen von Material der Pfahlnadel identifiziert. Die Analyse isolierter Anteile der lamellaren Zone zeigte ausschlie��lich ein 27 kDa Protein. Die restlichen Proteinbanden konnten hier nicht nachgewiesen werden. Das 27 kDa Protein reagierte im Westernblot mit Antik��rpern gegen Silicatein aus S. domuncula. Ein weiteres Protein wurde n��her charakterisert. Ein positiver Agglutinationsassay wies ein lectin��hnliches Molek��l innerhalb der Nadeln nach, wie es aus S. domuncula bekannt ist. Nach einer Deglycolysierung der Proteine reduzierte sich das scheinbare Molekulargewicht der 36 kDa Bande auf 30 kDa. Durch molekularbiologische Untersuchungen wurde erstmals in Hexactinelliden die Existenz von Silicatein nachgewiesen. Nach Isolierung der Gesamt-RNA von Crateromorpha meyeri, RT-PCR und Amplifizierung mit silicateinspezifischen Primern wurde eine 549 kBp Nukleotidsequenz gefunden, die auf Aminos��ureebene starke Homologien (76% identische Aminos��uren) zu bekannten Silicateinen der Demospongia aufweist. Die Aminos��uren der katalytische Triade des Silicateins, essenziell f��r die enzymatische Katalyse des Enzyms, sind an den selben Positionen wie bei bekannten Silicateinen vorhanden.

Comparison of x-ray crystal structures of an acyl-enzyme intermediate of subtilisin Carlsberg formed in anhydrous acetonitrile and in water

The x-ray crystal structures of trans-cinnamoyl���subtilisin, an acyl-enzyme covalent intermediate of the serine protease subtilisin Carlsberg, have been determined to 2.2-��� resolution in anhydrous acetonitrile and in water. The cinnamoyl���subtilisin structures are virtually identical in the two solvents. In addition, their enzyme portions are nearly indistinguishable from previously determined structures of the free enzyme in acetonitrile and in water; thus, acylation in either aqueous or nonaqueous solvent causes no appreciable conformational changes. However, the locations of bound solvent molecules in the active site of the acyl- and free enzyme forms in acetonitrile and in water are distinct. Such differences in the active site solvation may contribute to the observed variations in enzymatic activities. On prolonged exposure to organic solvent or removal of interstitial solvent from the crystal lattice, the channels within enzyme crystals are shown to collapse, leading to a drop in the number of active sites accessible to the substrate. The mechanistic and preparative implications of our findings for enzymatic catalysis in organic solvents are discussed.