Preparation of extracellular polysaccharide from fermentation liquor of marine microalgae Schizochytrium and study on the bioactivities

The ethanol precipitation was executed to extract exopolysaccharide from the fermentation solution of marine microalgae Schizochytrium sp.TIO1101.The extracted exopolysaccharide solution was then applied to 732 cationic exchange resin for further separation,the elution was isolated with into three major polysaccharide components: acidic polysaccharide,weak alkaline polysaccharides and alkaline polysaccharides.And the polysaccharides were assessed for antioxidant activity against reducing power activity,DPPH radical scavenging activity and hydroxyl radical scavenging activity assays,respectively.The results indicated that weak alkaline polysaccharides showed significant antioxidant activity.Antifungal activity experiment showed all three polysaccharide components demonstrated antifungal activity to Physalospora piricola,Pythium aphanidermatum,Botrytis cinerea and Fusarium pathogens to some extent,particularly showing high effect on Botrytis cinerea.