Optimization of Liquid Fermentation Medium Formulation of Morchella eohespera Exopolysaccharide and Its Hypoglycemic Activity in Vitro

In this study, strains of wild Morchella eohespera in Gansu province were selected as the research object to explore the optimal solution of liquid fermentation medium of M. eohespera extracellular polysaccharide and its hypoglycemic activity in vitro. A single factor experiments were conducted to compare the effects of seven additives, including brown sugar and corn meal, on the content of M. eohespera extracellular polysaccharide during liquid fermentation. On this basis, response surface methodology was used to optimize the liquid fermentation medium formula of M. eohespera exopolysaccharides. The hypoglycemic activities of extracellular polysaccharide from M. eohespera on α-amylase and α-glucosidase were determined in vitro. The results showed that when the amounts of addition of brown sugar was 2.20 g/L, urea was 3.18 g/L and corn flour was 2.40 g/L, the actual content of extracellular polysaccharide of M. eohespera could reach 1.20 g/L. At the concentration of 1.0 mg/mL, effects of extracellular polysaccharide of M. eohespera on α-glucosidase and α-amylase showed that the inhibition rates for these enzymes were 73.46% and 36.37%, respectively. The results showed that extracellular polysaccharide of M. eohespera was with hypoglycemic activity.