Extraction and separation of pigments from Saccharina latissima using eutectic solvents

• A sustainable process to extract pigments from Saccharina latissima is proposed. • The Menthol-Levulinic Acid eutectic solvent (ES) yielded the best extractions. • A biphasic system ES-ES is proposed for the separation of pigments. • Water as an antisolvent allowed the polishing of the fucoxanthin-rich fraction. Harnessing the untapped potential of marine biomass has emerged as a pivotal strategy to address growing demands for natural bioactive compounds across many industries. Among these, Saccharina latissima , a prolific marine alga, is a rich source of fucoxanthin and chlorophylls — molecules of significant biotechnological interest. This work used Saccharina latissima as a source of pigments to develop an integrated platform to promote the extraction and separation of chlorophyll and fucoxanthin using eutectic solvents (ES). Hydrophobic ES were investigated in the extraction of these pigments, and operational conditions were optimised. Among four hydrophobic ES screened, the Ment:LevA system, enhanced with 20 % (v/v) of water, exhibited the greatest potential, yielding an optimised extract rich in fucoxanthin with 137.2 ± 2.6 µg fucoxanthin ·g biomass -1 . Additionally, a unique ES-ES biphasic system facilitated the selective partitioning of pigments: chlorophylls predominantly remained in the hydrophobic phase, while 95 % of fucoxanthin migrated to the hydrophilic. To further refine the quality of the extracted fucoxanthin, a subsequent purification step using water was implemented successfully, resulting in a concentrated pigment product. This work highlights ES as potential biocompatible solvents for the recovery of value-added compounds from marine biomass.