Extraction of water-soluble polysaccharides in Pleurotus eryngii mycelia and optimization of cultivation conditions.

The orthogonal test was carried out in order to optimize cultivation conditions producing polysaccharides of Pleurotus eryngii mycelia using potato-dextrose synthetic medium(PDP)as basal medium. The effect of cultivation conditions including inoculum size,rotation speed of rocking bed and cultivation time on polysaccharides contents was investigated. Polysaccharides were extracted by dissolving the mycelia firstly in water and then precipitating it in ethanol and polysaccharides content was determined by phenol-sulfuric acid colorimetric method. The results showed that the optimal cultivation conditions were that inoculum size was 1 piece of 1 cm2 innoculum,rotation speed was 140rpm and cultivation time was 8 days. Under these conditions,polysaccharides content of Pleurotus eryngii mycelia was the highest,up to 75.1 mg/g.