Advancement in microalgal metabolites extraction techniques: Multi-factorial considerations

Microalgae are a rich source of high-value metabolites such as lipids, pigments, proteins, and polysaccharides, yet their recovery is limited by the complexity of cell wall structures and costly downstream processing. This review evaluates advanced green extraction techniques including enzyme-assisted (EAE), ionic liquid (ILs), microwave-assisted (MAE), milking, pressurized liquid (PLE), pulsed electric field (PEF), supercritical fluid (SFE), and ultrasound-assisted extraction (UAE). Here we also provide a multi-factorial comparative analysis incorporating cost, scalability, extraction efficiency, and environmental impact. The results indicate that EAE and SFE achieve the highest yields (up to 97 %) but are constrained by cost, whereas UAE and PEF balance scalability and sustainability, with UAE reducing extraction time by up to 60 % compared to conventional methods. Integrated approaches (e.g., ILs + SFE, UAE + EAE) show promising synergies, enhancing yield while reducing solvent demand. Overall, this review offers research advancements and insights on selecting the most appropriate extraction strategy depending on industrial priorities, thereby advancing sustainable commercialization of microalgal metabolites.