From Solvents to Solutions: Deep Eutectic Solvents for Circular Seaweed Biorefineries

Seaweed is a promising renewable resource for producing food ingredients, materials and other valuable compounds. However, processing seaweed into multiple products can require several processing steps and chemicals, which are not always recovered or reused. This PhD research explored whether deep eutectic solvents (DES) can help make these processes more circular. DES are liquid mixtures whose properties can be tailored to extract different compounds. The research focused not only on extracting valuable compounds such as alginate and fucoxanthin from brown seaweed, but especially on what happens afterwards: how the products can be separated from the DES and how the solvents can be recovered and reused. Different recovery and reuse approaches were developed and compared. The results show that DES can combine several functions within a single process and, when effectively recycled, reduce the need for new materials and the generation of waste. These findings contribute to the development of more circular and resource-efficient biorefineries for renewable biomass.