Emerging seaweed extraction techniques: Supercritical fluid extraction

Macroalgae, also named seaweeds, have been noted as promising feedstocks for biorefineries due to their high biomass productivity, less fresh water demand, no fertilizer requirement, and no requirement of arable land compared to terrestrial plants. Furthermore, macroalgae are rich in polysaccharides, proteins, lipids, and antioxidants that can be utilized resulting in many high-value metabolites supplying various industrial applications. Nevertheless, these substances are still unaffordable and not abundantly available. To overcome this demand, the development of an apt separation technology able to provide large quantities of these substances with high-quality is needed. Here, the highlight of supercritical carbon dioxide (CO2) and subcritical water on the useful compounds extraction from macroalgae-matrix is described. These extraction techniques have been intensively utilized to extract useful compounds from various plant materials. As green separation techniques, these treatments are desirable for their environmental merits and sustainability. The perspective and challenge for utilizing supercritical CO2 and subcritical water as macroalgae extraction media are also presented.