Green extraction of lipids: Exploring the capabilities of subcritical fluid technology

Conventional lipid extraction methods face three critical limitations: reliance on toxic organic solvents (hexane/chloroform), inability to process wet biomass without energy-intensive drying, and thermal degradation of omega-3 polyunsaturated fatty acids. This review critically assesses Subcritical fluid technology (SFT) as a sustainable alternative. SFT utilizes non-toxic solvents (water, ethanol, dimethyl ether) at moderate temperatures (100–250°C) and pressures (10–100 bar) below critical points, offering tunable polarity (ε = 80→25), gas-like diffusivities, and direct wet biomass processing. These properties enable selective lipid extraction with yields exceeding 90%, preservation of thermolabile bioactives (EPA/DHA retention >90%), and elimination of toxic residues. SFT demonstrates superior environmental, economic (energy savings 20–40%), and quality outcomes across microalgae, marine by-products, and oilseeds. This review provides a comprehensive framework, positioning SFT as a potential cornerstone for sustainable high-value lipid production across food, nutraceutical, and pharmaceutical industries, while identifying future research priorities in scalability and circular bioeconomy integration.