Tuning bioactive compound recovery from Chlorella vulgaris through surfactant-assisted ethanol extraction under microwave and pressurized liquid technologies

Chlorella vulgaris is a promising source of bioactive compounds such as polyunsaturated fatty acids (PUFAs), pigments, and antioxidants, whose recovery strongly depends on extraction conditions. In this context, surfactant-assisted extraction remains poorly explored for microalgae processing, particularly using green solvents and intensified extraction technologies. This work evaluated the effects of different surfactants (CTAB, SDS, and Triton X-100) on microwave-assisted extraction (MAE) and pressurized liquid extraction (PLE) of C. vulgaris using ethanol as solvent, in comparison with Soxhlet extraction using ethanol and hexane. Extraction yield, antioxidant activity, pigment concentration, and fatty acid profiles were investigated. Soxhlet extraction with ethanol provided the highest overall extraction yield, while hexane favored the recovery of a broader fatty acid profile and higher pigment contents. MAE using pure ethanol achieved comparable yields in substantially shorter extraction times and produced extracts with high antioxidant activity and chlorophyll recovery, indicating strong potential for rapid recovery of bioactive compounds from C. vulgaris. In contrast, surfactants showed limited influence under the evaluated MAE conditions. For PLE, extraction behavior was strongly affected by temperature and surfactant presence. Under pure ethanol conditions, increasing temperature reduced extraction yield, phenolic content, and chlorophyll recovery, while increasing antioxidant activity, suggesting changes in extraction selectivity rather than simple extraction enhancement. Triton X-100 modified extraction behavior depending on temperature, increasing extraction yield and altering antioxidant and pigment recovery under both evaluated conditions. Overall, the results suggest that surfactant-assisted PLE may act as a tunable extraction strategy capable of producing extracts with distinct compositional and bioactive profiles under mild processing conditions.