Green biorefinery of Laminaria hyperborea industrial side-streams: Subcritical water extraction optimization via response surface methodology

Artikel i vetenskaplig tidskrift, 2026

An integrated response surface methodology (RSM) approach for optimizing subcritical water extraction (SWE) of biopolymers and bioactive compounds from Laminaria hyperborea side-streams has been comprehensively developed. Temperature (110–140 °C), solid-to-liquid ratio (1:20–1:35 g:mL), and time (10–20 min) were evaluated on four key responses: yield, soluble protein, phenolic content, and molar mass. Temperature emerged as the most influential factor followed by extraction time and quadratic temperature effects. Building upon these findings, a multi-response optimization identified the targeted optimal conditions, achieving a desirability score of 0.802 under 130.2 °C, 1:28.5 g:ml, and 15.9 min. These conditions recovered up to 22% of the original biomass as an extract rich in fucose and uronic acids, indicative of fucoidan and alginate enrichment. Complementary downstream strategies demonstrated non-cytotoxicity, antioxidant and anti-inflammatory capacities in HaCaT keratinocytes. Findings encourage SWE adoption as a green technology in sustainable algal biorefinery and circular bioeconomy implementation.