Fermentation characteristics in stirred-tank reactor of exopolysaccharides with hypolipidemic activity produced by Pleurotus geesteranus 5#

Abstract

In this study, the hypolipidemic effect of exopolysaccharides (EPS) from Pleurotus geesteranus 5# fermenting liquor by the optimal culture conditions in a 5-L stirred-tank reactor was investigated. The hypolipidemic effect of the polysaccharide, investigated in streptozotocin induced diabetic mice, decreased plasma glucose, total cholesterol and triacylglycerol concentrations by 17.1 %, 18.8 % and 12.0 %, respectively. The results of the present investigation strongly demonstrate the potential of this polysaccharide to prevent hyperglycemia in the experimental animals. Under optimal culture conditions, the maximum concentrations of mycelial and EPS were 22.63 g/L after 7 d cultivation and 11.09 g/L after 10 d, respectively. Furthermore, the morphological parameters (i.e. mean diameter, circularity, roughness and compactness) of the pellets and the broth viscosity were characterized. It was proved that compactness of the pellet morphology (R²=0.963, p<0.01) was significantly and positively determined with mycelial biomass. Moreover, mean diameter (R²=93.3, p<0.01) and broth viscosity (R²=0.950, p<0.01) were significantly and positively determined with EPS content.