Purification,Antioxidant Activity And Kinetic Model Of Exopolysaccharides From Fermentation Liquid Of Ganoderma Sinense

Ganoderma Sinense is one species of the Ganodermataceae fungi, which is used to be a valuable medicinal herbs with the high value of medicinal function.This study detected great value of Ganoderma Sinense through modern biotechnology. The general content such as optimizing the culture conditions, establishing the synthetic characteristic of extracellular polysaccharides of Ganoderma Sinense performed in batch fermentation had been studied, Purifing the exopolysaccharide from Ganoderma Sinense and its antioxidant activity were also studied.The synthetic characteristic of exopolysaccharides of Ganoderma Sinense performed in batch fermentation had been studied fristly. The result indicated.that the production of extracellular polysaccharides was partially growth-associated. So the kinetic models were proposed by using the Logistic equation and the Luedeking-Piret equation, The calculated results of models were coincided with experimental data, the fitting degree of three models were:97.7%.94.3%and95.7%respectly. So the kinetic model could be used as practically reference guiding for producing extrac-ellular polysaccharides in fermentation of Ganoderma Sinense.Ganoderma Sinense exopolysaccharides were isolated though the steps such as ethanol precipitation, removing of proteins by polyamide, ionexchange chromatography of DEAE-52.The experimental results of stepwise ethanol precipitation showed that at the ethanol concentration of75%, exopolysaccharides contents are up to95%;Three methods (Sevag method,Polyamide method and active carbon method) were used to remove protein from polysaccharides.The results showed that PA method was better than the others,the removed percentage of protein could reach86.3%, and the lossing of polysaccharides was only25.6%; The exopolysaccharid-es of Ganoderma Sinense were isolated though DEAE cellulose-52anion exchange column, The results showed that three polysaccharide subfractions(GSP1,GSP2,GSP3) were isolated by eluted with Tirs-HCl Buffer with0.1,0.2,0.3M NaCl solutions at a flow rate of1.0mL/min. Three polysac-charide components respectively accounted for67.7%,18.1%and14.1%.The antioxidant activity of purified exopolysaccharides was measured by DPPH", O", and OH" free radicals scavenging methods. The results showed that three polysaccharides all had antioxidant activities in vitro. Among which, GSP2had a higher antioxidant activity with76.3%of scavenging hydroxyl radical at1.6mg/mL and81.5%at5mg/mL.GSP1and GSP2’s antioxidant activities with about35%of scavenging hydroxyl radical. The strength of antioxidant activities of three polysaccharides were:I(GSP2)>I(GSP1)>I(GSP3).