José Vladimir Oliveira

This work investigates the continuous production of alkyl esters from soybean fatty acid (FA) charges using immobilized Novozym 435 as catalyst. The experiments were performed in a packed-bed bioreactor evaluating the effects of FA charge to alcohol (methanol and ethanol) molar ratio, from 1:1 to 1:6, substrate flow rate in the range of 0.5–2.5 mL/min and output irradiation power up to 154 W, at fixed temperature of 65 °C, on the reaction conversion. Results showed that almost complete conversions to fatty acids ethyl esters were achieved at mild ultrasonic power (61.6 W), FA to ethanol molar ratio of 1:6, operating temperature (65 °C) and remained nearly constant for long-term reactions without negligible enzyme activity losses.

In this work, the separation of refined soybean oil/n-hexane mixtures was investigated using a commercial hollow fiber ultrafiltration membrane 50 kDa. Three alcohols with different chain lengths were tested for the conditioning of the membrane; n-propyl alcohol showed the highest n-hexane permeate flux after conditioning. There was a decrease in the rejection and an increase in permeate flux over time. This behavior may be related to swelling and membrane plasticization by the oil. Rejections from 10.0 to 28.7% and total permeate fluxes from 12.2 to 65.3 kg/m²h were observed. An increase in the oil/n-hexane mass ratio and the pressure caused an increase in the rejection and permeate total flux for most assays. No degradation was observed in the membrane module.

This research note addresses the role of organic solvent amount in the production of fatty acid ethyl esters from soybean oil. N-hexane was chosen as solvent and two commercial immobilized lipases as catalysts, Novozym 435 and Lipozyme IM. The reactions were conducted in 6 hours, varying the solvent to oil ratio from zero to 50 (v/wt) and adopting adopting for Novozym 435: 65 ºC, enzyme concentration (E, wt%) = 5, oil to ethanol molar ratio (R) = 1:10, water addition (H, wt%) = 0, and for Lipozyme IM: 35 ºC, E = 5 wt%, R = 1:3, H = 10 wt%. For Lipozyme IM, an increase in solvent amount is shown to lead to an enhancement of reaction conversion, while a negligible effect was found for Novozym 435. When using 30 mL of solvent the reaction conversions were 88% for Lipozyme IM and 15% for Novozym 435.

In this work, the essential oils of S. officinalis, S. sclarea, S. lavandulifolia and S. triloba were chemically analyzed by gas chromatography coupled to a mass spectrometry detector (GC/MSD), and their antimicrobial activity was tested against 10 microorganisms using the disk diffusion method and the Minimum Inhibitory Concentration (MIC) technique. The following major compounds were identified in the essential oils: α - and β-thujone, camphor and 1,8-cineole, except in S. sclarea, where linalool, linalyl acetate and α-terpineol were the major constituents. The antimicrobial activity showed significant differences (p < 0.05) only when obtained by the MIC method. Gram-positive microorganisms presented larger sensitivity for the essential oils. The lowest MIC was observed when Staphylococcus aureus was exposed to 2.31 mg.mL-1 of S. lavandulifolia essential oil, while the highest MIC value was obtained when Shigella flexneri was exposed to 9.25 mg.mL-1 of the same essential oil, thus demonstrating that this essential oil may be effective as a bacteriostatic agent against Gram-positive microorganisms. Neste trabalho os óleos essenciais de S. officinalis, S. sclarea, S. lavandulifolia e Salvia sp. foram analisados quimicamente por cromatografia gasosa acoplada a espectrômetro de massas. A atividade antimicrobiana dos óleos essenciais foi testada contra 10 microrganismos utilizando o método de difusão em discos e através da determinação da Concentração Inibitória Mínima (CIM). Cânfora, α - e ß-thujone e 1,8-cineol foram os compostos majoritários identificados na maioria dos óleos essenciais, exceto para S. sclarea, em que linalol, acetato de linalil e α-terpineol foram os compostos majoritários identificados. As atividades antimicrobianas apresentaram diferenças significativas (p < 0,05) somente quando obtidas pelo método CIM. Microorganismos gram-positivos apresentaram grande sensibilidade para os óleos essenciais. A menor CIM foi observada para o Staphylococcus aureus quando exposto a 2,31 mg.mL-1 de óleo essencial de S. lavandulifolia, enquanto que a maior CIM foi observada para Shigella flexneri exposta a 9,25 mg.mL-1 do mesmo óleo essencial, provando que este óleo constitui-se em um eficiente agente bacteriostático contra microrganismos gram-positivos

O presente trabalho tem por objetivo reportar valores experimentais de condutividade térmica e viscosidade dinâmica dos óleos vegetais refinados de soja, milho, girassol, algodão, canola, oliva e de farelo de arroz. As medidas de condutividade térmica foram realizadas em célula acoplada a um banho termostático no intervalo de temperatura de 20 a 70 °C, utilizando uma sonda de fio quente. Os resultados obtidos demonstram que para todos os óleos vegetais investigados a condutividade térmica possui fraca dependência com a temperatura, apresentando ligeiro decréscimo com o aumento desta variável. O método gravimétrico foi empregado para a medida da densidade dos óleos vegetais estudados à temperatura ambiente, não tendo sido verificada diferença significativa entre os valores encontrados. Para as medidas de viscosidade dos óleos vegetais foi utilizado um viscosímetro do tipo Brookfield, acoplado a um banho termostatizado com controle de temperatura. A partir dos resultados obtidos verificou-se que a viscosidade decresce acentuadamente com o aumento da temperatura para todos os óleos vegetais. This work reports experimental data of thermal conductivity and dynamic viscosity of the following refined vegetable oils: rice, soybean, corn oil, sunflower, cottonseed, and olive oil. Measurements of thermal properties were carried out in a cell coupled to a thermostatic bath in the temperature range of 20-70 °C, using a single-needle stainless steel sensor. It was experimentally observed that the thermal conductivity decreased slightly with increasing temperature for all samples investigated. The gravimetric method was employed for density data acquisition, and revealed no significant difference among the values obtained. The Brookfield apparatus was employed in measuring the dynamic viscosity and it was verified that a raise in temperature led to a sharp decrease for this property for all samples investigated

This work reports the application of a lipase in the glycerolysis of olive oil for the production of monoacylglycerols (MAG). For this purpose, the enzymatic glycerolysis of olive oil with an immobilized lipase (Novozym 435) was accomplished using sodium (bis‐2‐ethyl‐hexyl) sulfosuccinate (Aerosol‐OT or AOT) as surfactant in a solvent‐free system. A sequential strategy was used applying two experimental designs to optimize the MAG production. In general, it was observed that the temperature had a negligible effect on MAG conversion while the enzyme and AOT concentrations present a positive significant effect (p <0.05) and the stirring rate a negative one. An empirical model was then built so as to assess the effects of process variables on the reaction conversion. Afterwards, the operating conditions that optimized MAG production were established as follows: temperature of 70 °C, stirring rate of 600 rpm, 16 wt‐% of AOT and 7.5 wt‐% of enzyme, leading to a reaction conversion as high as 55%.

This work reports the effects of temperature (20 to 50ºC) and pressure (100 to 250 bar) on the extraction yield, chemical characteristics and antimicrobial activity of extracts of Peumus boldus Molina obtained by compressed carbon dioxide extraction. Results showed that the extraction variables affect the extraction yield and the chemical distribution of the major compounds present in the extracts. The extracts were chemically analyzed with regard to 1,8-cineole, trans-sabinene, pinocarveol, pinocarvone, 4-terpineol, ascaridole, piperitone oxide, limonene dioxide and n-eicosane in a GC/MSD. Antimicrobial tests demonstrated that the high-pressure CO2 extracts had activity against 13 bacteria and that better action was verified with extracts obtained at a lower CO2 extraction density and a higher temperature