Avaliação de tecnologias ambientalmente sustentáveis para extração de compostos bioativos

Abstract

Extracts, essential oils and isolated chemical compounds of vegetable origin have been increasingly used, not only as raw material for industries of different branches, but also as an alternative in the treatment of health problems by the population in general. Considering the expressive importance of producing these substances with high quality and affordable price, the present work had the objective of the technical and economic analysis in obtaining bioactive compounds from the plant species Artemisia annua and Varronia curassavica. Aiming to select and test three environmentally sustainable extraction technologies, supercritical carbon dioxide, cold maceration with the ethanol and steam distillation, a protocol of high yield and low cost to obtain bioactive compounds of plants was proposed. For the supercritical carbon dioxide extraction, the influence of temperature, pressure and volume of cosolvent (ethanol) on the extraction yield and purity of the extracts was investigated. Three experiments with a completely randomized design in factorial arrangement were performed. For the A. annua, three temperatures (40/50/60 ºC), 3 pressures (200/250/300 bar) and 3 levels of cosolvents (0/15/25%) were tested; and for V. curassavica 2 temperatures (40/60 ºC), 5 pressures (100/150/200/250/300 bar) and fractional extraction. The extractions with steam distillation were conducted at ambient pressure for 3 - 4 h, and cold maceration with ethanol was carried out in series, at ambient pressure for 6 h, conditions being the best referenced. At the end of the experiments the yields and purity of the extracts and essential oil were compared and used for the implementation of industries of biocomposites production using the technologies tested. Through the research of costs involved in the project implementation and the use of spreadsheets in Microsoft Office Excel, it was calculated the Costs of Production and Maintenance and Direct Fixed Capital; on the sequence, using the Software SuperPro Designer® and the Web Application $AVEPI, the computational simulations were conducted generating the economic indicators on the feasibility and risks of implantation of the industries of extraction of artemisinin from A. annua, and essential oil from V. curassavica. It was observed that the extraction of artemisinin with supercritical carbon dioxide obtained lower yields of extract than the extraction with ethanol, but with higher purity of the target compound and lower costs of production. In the production of essential oil of V. curassavica the extraction with supercritical carbon dioxide reached the same yields and purity obtained by steam distillation. In the scenario studied the costs of operation and maintenance of the production of extracts with ethanol, supercritical carbon dioxide for A. annua, and supercritical carbon dioxide for V. curassavica, were shown to be greater than the revenue price of the extracts. For the A. annua plant, these results were attributed to the high costs of the raw material, and to V. curassavica the low yields of the extract. The investment project using steam distillation for the obtaining of V. curassavica essential oil showed to be promising due to the high profitability and low risk associated in the expected scenarios.