Liquid-Liquid Extraction of Fucoidan Leached from Brown Seaweeds
溶剂萃取法从褐藻浸提液中分离提取褐藻糖胶

Liquid-liquid extraction of fucoidan leached from brown alga was studied in the present work. Effects of contact time, diluent volume added and extractant concentration were investigated. Results show that the liquid-liquid extraction of fucoidan from brown alga with N263 is rapid and the equilibrium between two phases can be reached in 5~10 min, and the extraction of fucoidan is significantly influenced by diluent volume added and the more the diluent volume added, the lower the percent extraction. This phenomenon is much different from the prepared solutions in which the diluent amount added has little effect on the liquid-liquid extraction. For different brown alga, the results show that the liquid-liquid extraction is more easily for fucoidan leached from Laminaria japonica than from Sargassum thunbergii, and moreover, an ultrasonic breakage technology is more favorable than hot acidic aqueous solutions for the liquid-liquid extraction. Furthermore, the stripping of fucoidan with an aqueous inorganic salt solution was investigated. The results indicated that fucoidan in the organic phase can be stripped by an aqueous inorganic salt solution, the percent stripping increases with increasing salt concentration and decreasing volume ratio of organic to aqueous phases. The effects of addition of TOA (tri-n-octyl amine) into the organic phase on the liquid-liquid extraction and stripping of fucoidan were also studied and it is shown that the addition of TOA to the organic phase is favorable to both the liquid-liquid extraction of fucoidan and the stripping with aqueous inorganic salt solutions. Finally, fucoidan was prepared from Sargassum thunbergii with liquid-liquid extraction technology and its purity (higher than 40%) is much higher than that (about 20%) with alcohol precipitation.