Supercritical fluid extraction of carotenoids and chlorophyll a from Synechococcus sp.

Supercritical carbon dioxide extraction of carotenoids and chlorophylls is an alternative to solvent extraction because it provides a high-speed extraction process with a simple purification stage. In the study described here, carotenoid and chlorophyll extraction with supercritical CO2 was explored using dry biomass from a marine cyanobacterium Synechococcus sp. as the raw material. The operation conditions were as follows: pressures of 100. 200: 300. 400 and 500 bar, temperatures of 40, 50 and 60 degrees C. Analysis of the extracts was performed by measuring the absorbance and by using an empirical correlation. The results demonstrate that the highest extraction yield of total carotenoids is obtained operating at a pressure of 300 bar and a temperature of 50 degrees C. The most appropriate operating conditions to obtain the best yield in the extraction of chlorophyll a are 500 bar and 60 degrees C. The highest carotenoids/chlorophylls (Carot/Chlor) ratio is obtained at 200 bar and 60 degrees C. Under these operating conditions a higher selectivity is obtained and this should facilitate the separation and purification of the two extracted pigments. (C) 2006 Elsevier B.V. All rights reserved.