Evaluation of ultrasound assisted extraction of bioactive compounds from microalgae

This study investigated the effect of ultrasound assisted irradiation on the carotenoids and lipids extraction from the Chlorella vulgaris and Porphyridium purpureum microalgae in the presence of three solvents with various polarities (water, ethanol, and hexane) allowed in the food industry. The optimization of the ultrasound assisted extraction operational parameters (solvent composition, solvent to sample ratio, power) was realized using Response Surface Methodology based on a face-centered composite design (FCCD). The results of this study showed that the increased solvent polarity led to the maximum extraction yield of 6435.60 mu g/g in total carotenoid content. Regarding the distribution of carotenoid between the aqueous ethanolic phase and hexane, the highest yield of 5762.08 mu g/g carotenoid was obtained in hexane phase. Regarding the lipid content, the yield increased with the increase of ethanol concentration reaching a maxim value of 29.07 mg/g. Also, it was observed that, when single solvents were used for carotenoid extraction, the yields were much lower compared with mixtures solvents. For example, when hexane was tested the yield was of 226.87 mu g/g carotenoid, meanwhile for absolute ethanol the yield was of 2027.72 mu g/g The optimal parameters determined was applied for the extraction of carotenoids from Porphyridium purpureum microalgae. The results indicate a total carotenoid content of 947.25 mu g/g and 21.59 mg/g lipids. The analysis of fatty acid profile of both microalgae biomass in ethanolic and hexane phase indicated the selective accumulation of saturated and polyunsaturated fatty acids in hexane and respectively in ethanolic phase.

Automated summary

This study investigated the effect of ultrasound assisted irradiation on the extraction of carotenoids and lipids from Chlorella vulgaris and Porphyridium purpureum microalgae. The results showed that the use of mixed solvents led to higher extraction efficiencies, and that the solvent polarity, composition, and solvent/sample ratio all impacted the extraction efficiency.