Crude Fucoidan Extraction from Seaweed

The chemical extraction of crude fucoidans was performed in 0.1 M HCl solution with a ratio of seaweed to extracting liquid of 1:20 and treatment for 3 h at 70 °C (methodology modified from Ale et al. 2012 [53 (link)]). The supernatant (Extract A, Figure 5a)) was collected by centrifugation for 10 min. at 19000 rpm. Next, 2% CaCl₂ solution was added to remove alginate as a precipitate after centrifugation (Figure 5). The crude fucoidans were isolated from the supernatant by 72% ethanol (EtOH), recovered by centrifugation at 19000 rpm for 30 min, and lyophilized. The latter steps were comparable to the enzyme-assisted extraction method (Figure 5).