Improved fatty acid extraction from microalgae with a novel combined process pulsed electric field-supercritical CO₂ extraction

Microalgae are a sustainable alternative to source for high-value fatty acids (FAs) with production potential nutraceutical, pharmaceutical, and biofuel applications. Traditional extraction techniques, however, have faced challenges like low yields, solvent toxicity and energy-intensive operations. A novel integrated PEF-scCO2 extraction strategy promise to release the maximum fatty acids yield with optimal quality directly from Chlorella vulgaris without even needing organic extraction solvents. The FAs were selectively extracted from the PEF pre-treated cells as step 1 of the tri-extraction procedure using scCO2. Optimization of PEF and scCO2 conditions are being executed with response surface methodology (RSM) with a core integrated method, involving testing several process factors. The lowest Y selectivity (38.2% yield) was obtained with the integrated PEF-scCO2 technique, whereas use of the GC-MS technique for fatty acid analyses slightly improved Y selectivity (41.2% yield) over Y selectivity (41.1%) using the other techniques. Both were significantly higher in comparison with the values obtained by conventional solvent extractions (hexane and chloroform) and the standalone scCO2 extraction. The economic analysis revealed that cost-effectiveness was achievable if carried out in an industrial scale, suggesting high prospects of this integrated method for sustainable and high valuable FA production from microalgae.