abstract
Acacia dealbata Link. is an invasive species with a negative impact on forest production areas. Its removal generates large amounts of residues (biomass) that can be burned for energy production or extracted to obtain high-value compounds, such as triterpenoids of the lupane, ursane and oleanane families, with known bioactive properties. The extraction can be performed with conventional organic solvents or by supercritical fluid extraction (SFE) with CO2 which is a greener alternative. In this work, SFE of A. dealbata Link. leaves was studied in order to identify and optimize the SFE parameters (pressure: 200-300 bar; temperature: 313.15-353.15 K; and addition of ethyl acetate as cosolvent: 0-10 wt%) that enhance productivity and selectivity towards specific triterpenoids. Even though Soxhlet extraction with dichloromethane provided higher total extraction yield (eta Total = 3.8 wt% versus 2.1-3.2 wt%, for SFE), SFE surpassed Soxhlet results in terms of individual yields and con-centrations of squalene, alpha-tocopherol, alpha-amyrone, beta-amyrone, and lupenone. For these five compounds the SFE yield reached 0.8043 wt% and the extract concentration reached 35.5 wt% (15.1 % and 95.1 % higher than with Soxhlet extraction, respectively). Particular emphasis should be given to lupenone, with a maximum yield of 0.4748 wt% and a concentration of 22.9 wt% in the SFE extracts obtained at 250 bar, 313.15 K and no cosolvent (ethyl acetate). The optimum conditions of pressure, temperature and ethyl acetate content depended on the response. Productivity, eta Total, was maximized by increasing all three factors to its maximum conditions. Tem-perature was one of the most impactful parameters on the individual triterpenoids SFE yields with lower tem-peratures enhancing the selectivity.
keywords
RESPONSE-SURFACE METHODOLOGY; OPERATING-CONDITIONS; CURVES; BIOMASS; YIELDS; ACIDS; OIL
subject category
Engineering
authors
Rodrigues, VH; Portugal, I; Silva, CM
our authors
Carlos Manuel Silva
Associate Professor
Inês Portugal
Assistant Professor
Vitor Hugo dos Louros Rodrigues
PhD StudentProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC) . Authors want to thank Project inpactus-innovative products and technologies from eucalyptus, Project N 21874 funded by Portugal 2020 through European Regional Development Fund (ERDF) in the frame of COMPETE 2020 n 246/AXIS II/2017.