RESUMEN
The use of new materials in the field of biofuel production has been represented as a step in the development of remarkable catalysts. The use of lipases in the production of biodiesel is often seen as a cost-limiting step, as the operating expenses in recovering such catalysts can lead to unfeasible market expectations. In this study, hydroxyapatite (HAp) particles were evaluated as a support to immobilize commercial lipase, following application in ethyl ester synthesis. First, hydroxyapatite was synthesized through the co-precipitation method at constant pH and selected as a support to be used in enzyme immobilization. The characterization of the biocatalyst support materials produced was carried out using DRX, BET, FTIR, TGA, and SEM analysis. The lipase from Thermomyces lanuginosus was then immobilized in the matrices, and, subsequently, there was transesterification of the vegetable oil deodorization distillate (VODD). The biodiesel samples generated showed that they were within commercial standards, achieving ester conversion greater than 96.5%. Other properties such as density (0.87 g.cm-3) and viscosity (4.36 mm2.s-1) meet the specifications required by ASTM to be used as a biofuel. In the experiment planning technique, the results revealed an experimental trend and a defined behavior: a higher lipase loading in the immobilization and the use of temperatures in the range of 40-50 °C favor high conversions of ethyl esters. Thus, this confirms that the enzymatic chemical catalyst was able to form the main fatty acid esters even using a residual lipid raw material.
RESUMEN
Among the most important tropical fruit grown in the world today and in Brazil, papaya occupies a prominent place. Native to tropical America, papaya has spread to several regions of the world, and Brazil accounts for 12.74% of the world production, followed by Mexico, Nigeria and India. The culture reached a harvested area of 441,042 ha and production of 12,420,585 t worldwide. The largest interest in this fruit relies on its main constituent compounds, like vitamins A, B and C, alkaloids (carpaine and pseudocarpaine), proteolytic enzymes (papain and quimiopapain) and benzyl isothiocyanate, more known as BITC, which has anthelmintic activity. Because of that, the present work has as objective the evaluation of the efficiency and composition of the oil extracted from Carica papaya L. seeds with supercritical carbon dioxide. The experiments were performed in a unit containing mainly a high-pressure pump and a stainless steel extractor with 42 mL of volume. The sampling was performed at each 20 min until the saturation of the process. About 6.5 g of sample were fed for each experiment done at 40, 60 and 80 °C under the pressures of 100, 150 and 200 bar. Samples of the Carica papaya L. fruit were acquired in a popular market and free for personal use intended for the study. After collection, the seeds were crushed with the help of a pestle, and dried at 60 °C for 60 min. For each operational condition, the extraction curves were constructed relating cumulative mass of oil extracted in function of the operational time. The better efficiencies were found at 40 °C and 200 bar (1.33%) followed by 80 °C and 200 bar (2.56%). Gas chromatography and NMR analysis could identify an insecticide component (BITC) that enables new applications of this residue in pharmaceutical and chemical industries.