Extraction and Biological Activities of Polysaccharides from Fermented Mycelia of Lachnum calyculiforme

The fermented mycelia of Lachnum calyculiforme YM-262 were extracted with hot water to produce polysaccharides.The effects of temperature of hot water,extraction duration and liquid/material ratio(V/m) on yield of polysaccharides were investigated by one-factor-at-a-time method.Subsequently,the factors were optimized to attain the maximum yield of polysaccharides using a three-factor and three-level orthogonal array design leading to a set of 9 experiments.Furthermore,polysaccharides obtained by optimized extraction procedure were analyzed for their antioxidant activity and antimicrobial activity.The optimum conditions for extraction of polysaccharides were determined as follows:with a ratio of liquid to material of 70:1,extraction at 80 ℃ for 4 h,and a yield of polysaccharides of 9.16% was achieved by the optimized extraction procedure.The polysaccharides were found to possess considerable antioxidant activity —their scavenging rate to DPPH radicals was 18.88% at 30 mg/L,to hydroxyl radicals 50.43% at 40 mg/L,and to superoxide anion radicals 85.53% at 100 mg/L.The polysaccharides also displayed certain antimicrobial activities to Escherichia.coli,Bacillus subtilis,Staphylococcus aureus and Saccharomyces cerevisiae,with a minimum inhibitory concentration(MIC) in the range of 15.61-62.5 μg/ml.