Abstract:

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.

Key words: polysaccharides, antioxidant activity, antimicrobial activity, Lachnum calyculiforme