Enzymatic Extraction and Purification of Fucoidan from Fucus distichus evanescens

Before the extraction, Fucus distichus subsp. evanescens brown algae was washed, lyophilized and grounded into a powder. The enzymatic extraction was performed as described in [21 (link)]. Briefly, dried seaweed was treated with Cellic^®CTec2 cellulase (Novozymes, Bagsværd, Denmark) and alginate lyase SALy from Sphingomonas sp. to break down non-fucoidan polysaccharide components of the cell and release fucoidan. High molecular weight alginate was removed by precipitating with CaCl₂. Fucoidans were further precipitated using ethanol. The crude fucoidan product was lyophilized for bioactivity studies (FE_crude). The aqueous solution of the crude fucoidan was further purified and fractionated using ion-exchange chromatography, obtaining three fractions (FE_F1, F2, F3) as previously described in [21 (link)]. Subsequently, the fractions were filtered through a 10 kDa membrane and lyophilized.