Study on the extraction and isolation and purification alginate from Costaria costata residues

The extraction of alginate from Costaria costata residues was studied by alkali test, then it was further isolated and purified.The optimum extraction condition by orthogonal test was as follows: 4.5 hours extraction time, 1∶ 40 ratio of solid to liquid, 3.5% Na2CO3 concentration and 70℃ extraction temperature, the crude yield was44.07%, with 94.77% content of sodium alginate.The viscosity was 14.8m Pa·s. Sodium alginate was further purified by D301- T weak- base exchange anion resin, two fractions ( F1 and F2) were obtained with the recovery yield of19.33% and 63.33%, which sodium alginate content of 84.56% and 89.69%, respectively. F1 and F2 were then separated by Sephacryl S-300 gel chrom atography, then the molecular weights of F1, F2 were estimated as 257 ku and 81 ku, respectively.