Estudo da atividade antibacteriana do picolinato de sacarose em Escherichia coli.Escherichia coli.

Os sucroésteres são empregados como surfactantes, tensoativos, substitutos de gordura e antibióticos. Este trabalho tem como objetivo sintetizar um novo sucroéster derivado do ácido picolínico (ácido 2-piridinocarboxílico), o picolinato de sacarose, e estudar sua atividade antibacteriana in vitrosobre a bactéria Gram-negativa patogênica Escherichia coli. A síntese do picolinato de sacarose foi processada a partir da transesterificação da sacarose com picolinato de metila em condição anidra à 80oC, utilizando dimetil sulfóxido (DMSO) como solvente e K2CO3 como catalisador. A separação dos isômeros formados foi realizada por HPLC no modo semipreparativo e cinco frações cromatográficas foram coletadas e aplicadas em testes de atividade antibacteriana, por disco-difusão em meio sólido, nas concentrações de 150; 300; 450; 600; 750 e 900 μg/mL. As frações 2, 4 e 6 foram ativas contra E.coli. e a fração 4 (900 μg/mL) foi a mais eficiente, sendo selecionada para testes em sinergia com EDTA nas concentrações de 250, 500 e 750 μg/mL, com melhor resultado quando empregado EDTA em 750 μg/mL. Neste caso, os discos apresentaram halos de inibição de crescimento igual ao da Tetraciclina (30 μg/mL) e superior aos produzidos pelos discos com Gentamicina (10 μg/mL). A fração 4 foi caracterizada por FTIR e espectrometria de massas (ESI-MS) e os resultados indicam que se trata sucroéster monossubstituído. Palavras-chave:Sucroquímica. Sucroéster. Sacarose. Picolinato de sacarose. Escherichia coli. Antibiograma por disco-difusão. ABSTRACT Study of antimicrobial activity of sucrose picolinate against Escherichia coli Sucrose esters are generally used as surfactants, fat substitutes and antibiotics. The aim of the present study was to synthesize new sucrose esters derived from picolinic acid (2-pyridine carboxylic acid) and study in vitro antimicrobial activity on the Gramnegative pathogenic bacterium Escherichia coli. The synthesis of sucrose picolinate was performed through the transesterification of sucrose with methyl picolinate under anhydrous conditions at 80 oC using dimethyl sulfoxide (DMSO) as the solvent and K2CO3as the catalyst. The separation of the formed isomers was performed by HPLC in a semi-preparative chromatograph system. Five fractions were collected and applied to a disc-diffusion antibiogram in solidmedium tests at concentrations of 150, 300, 450, 600, 750 and 900 μg/mL. Fractions 2, 4 and 6 were active against E. coli. Fraction 4 (900 μg/mL) was the most efficient and was selected for the determination of antimicrobial activity in synergistic tests with EDTA at concentrations of 250, 500 and 750 μg/mL. The best result was obtained with 750 μg/mL of EDTA. Fraction 4 was characterized as a monosubstituted sucrose ester by FTIR and mass spectrometry (ESI-MS). Keywords: Sucrochemistry. Sucrose. Chromium picolinate sucrose. Escherichia coli. Susceptibility testing by disk diffusion.

Chemical modification of the surface of alumina with alkaline earth metal oxides using the polymeric precursor method for catalysis application

In this study, modifications of alumina surface with of alkaline earth metal oxides were studied, using the polymeric precursor method. The modified compounds were characterized by X-ray diffraction, nitrogen adsorption-desorption and scanning electron microscopy. The catalytical properties of these new catalysts were evaluated for the transesterification reaction of babassu oil. It is observed that the transesterification reaction of babassu oil with methanol was successfully carried out using the modified alumina samples.

Lipases produzidas por fungos derivados de ambiente marinho: otimização, purificação e caracterização bioquímica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Imobilização de lipases por adsorção e ligação covalente em derivados de agarose e quitosana e sua aplicação em biocatálise

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Síntese, caracterização estrutural e análise do potencial catalítico do SrTiO3 e das Perovskitas duplas de Sr1-xKxTiCux/2O3, onde x = 0,2; 0,3 e 0,5, na preparação de biodiesel

Pós-graduação em Química - IBILCE

Preparação de soluções sólidas superficiais à base de alumina como catalisadores para síntese do biodiesel via rota etílica

Pós-graduação em Química - IBILCE

Desenvolvimento e validação de método analítico empregando cromatografia gasosa ultrarrápida para quantificação de teor total de ésteres em amostras de biodiesel

Pós-graduação em Química - IQ

Cytotoxic, biochemical and genotoxic effects of biodiesel produced by different routes on ZFL cell line

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Microalgas na Produção de Biodiesel: Extração e Composição Lipídica

The uninterrupted rise in emission of greenhouse gases open way to the use of biofuels, due to politics that focus on fuel safe, clean and renewable. The use of microalgae for biodiesel production has been described as one of the most promising sources of biomass for biofuels. The aim of this study was to evaluate the extraction and lipid profile of the microalgae Dunaliella tertiolecta, Isochrysis galbana and Tetraselsim gracilis. The extractions were performed with solvents chloroform /methanol and petroleum ether. The lipid profile was analyzed by gas chromatography after transesterification.The petroleum ether showed more efficiency in the extraction, the best result obtained was in the microalgae D. tertiolecta with 19.52% of lipid. The lipid profile analysis indicated a biodiesel stable to oxidation and elevated viscosity

Simulação computacional da extração líquido-líquido fracionada de enzimas para produção de biodiesel

Liquid-liquid extraction is utilized for purification of biomolecules by Aqueous Biphasic Systems (ABS), since this process does not damage the biotechnological potential of these compounds. In this work, using the free software Scilab®, the fractionated liquid-liquid extraction was studied aiming a lipase (target enzyme) partition in a water + PEG + DEX system. Lisozime was considered as contaminant. As computer simulations has been extensively used when a first estimation of technical feasibility of process is desired, this work demonstred that the system is viable for recovery the 80 % till 90 % the target enzyme, but should be noted that the trial aimed only the fractionation of the enzyme target of a contaminant, not its concentration, which should be done by another process.

Ethyl biodiesel: Microwave irradiation aiding ethanolysis of waste cooking oil.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação dos processos de tratamento do glicerol proveniente da produção do biodiesel

The substitution of diesel by biodiesel meets the current scenario to increase the consumption of alternative energy sources promoting sustainable development of a country. However, the production of biodiesel concurrently generates the formation of glycerine in the process is a by-product. The main application of glycerine is in the food industry, cosmetics, soaps, pharmaceuticals, among others, but these segments are not capable of absorbing the generated volume of glycerine, whereas the total volume of the biodiesel produced about 10% correspond to glycerine. Glycerine obtained from the transesterification reaction (necessary for production of biodiesel) triglycerides and alcohol contains certain impurities such as water, salts, esters, alcohol, and residual oil, which decrease the value. Thus, the purification process or the direct use of glycerine become essential to make it competitive biodiesel production process. This work aims to evaluate the different processes of purification and the use of glycerine obtained as by-product in the production of biodiesel. The research was theoretical, based on technical articles and theses published on this subject, and from these databases was established a summary of the most important processes

Lipases microbianas: produção, propriedades e aplicações biotecnológicas

Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)

Nanozeólitas como suportes sólidos para imobilização enzimática: Síntese, caracterização de complexos nanozeólitas/enzimas e sua aplicação como catalisadores heterogêneos para produção de biodiesel via rota etílica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determinação de fósforo em biodiesel utilizando eletrodo quimicamente modificado com nanopartículas de ferro

Once petroleum is na exhaustible source of energy, alternative fuels are having more prominence. A much discussed option for replacing fossil fuels is the use of biofuels derived from oils or fats, especially biodiesel. The biodiesel preparation is through a reaction named transesterification, a reaction of triglycerides with a short chain alcohol with a catalyst, producing a mixture of fatty acid esters and glycerol. According to ANP (National Petroleum Agency) specifications, biodiesel can have contaminants due to the catalyst or oil used on its synthesis, such as phosphorus, wich can damage the catalytic converter and cause significant increase in the particles emission. This project aims to develop na alternative method using chemically modified electrodes with iron nanoparticles for determination of phosphorus in biodiesel. For the formation of the iron nanoparticles film on the surface of a glassy carbon electrode, was used a iron sulfate solution. The film was formed after 10 successive cycles, with a scanning speed of 50 mV s-1 and a potential range of -0,9 to -1,25 V. To reduce possible oxides on the surface and activate the electrode, it has been subjected to a cathodic polarization with a potential of -1,25 V for 15 minutes in a sodium hydroxide solution. In cyclic voltammograms obtained in the study of the speed of scanning, there is an increase in the intensity of the anodic and cathodic current peaks. The cathodic peak current varied linearly with the square root of scan rate, showing that the electrode is controlled by diffusion. After successive additions of phosphate there is a linear variation in the current peak in the concentration range of 1,0 x 10-7 a 1,0 x 10-6 mol L-1. To determine if the concentration of phosphorus in real sample, the method of adding standard was used by adding aliquots of phosphate ions in the solution containing soy biodiesel extracted with ....