Abstract: Polysaccharide was extracted from Pleurotus eryngii wastes processed by ultrasonic or cellulase， with ethanol as extraction agent. Response surface experiments and orthogonal design were used to optimize the extraction process. Ultrasonic extraction and enzymatic extraction， both with the optimal parameters， were effectively combined to get the highest Pleurotus eryngii polysaccharide yield. The results showed that， the optimal ultrasonic extraction conditions were: water material ratio 30∶1， pH 6.0， ultrasonic power 100 W， extraction time 20 min， the yield of polysaccharide was 22.17%. The optimal conditions of enzymatic extraction were: water material ratio 25∶1， the amount of enzyme 0.80%， enzymatic hydrolysis temperature 60℃， enzymatic hydrolysis time 120 min， pH 5.5， the yield of polysaccharide was 26.48%. The combinations of the two methods gave the highest yield of 30.46%， which was 1.92 times higher than that by the traditional water extraction method.

Key words: Pleurotus eryngii, polysaccharide, ultrasonic, cellulase