| Summary: | 碩士 === 國立臺灣大學 === 食品科技研究所 === 94 === Polysaccharides from Ganoderma lucidum, a popular Traditional Chinese Medicine ingredient, have been associated with the antitumor, immuno-modulating and hypoglycemic activities of this mushroom. (1,3)-β-D-glucans bearing (1,6)-β-D glucosyl branches has been proved to be the major active component in the hot-water extractable polysaccharides. In this study, we employed ethanol fractional precipitation, ultra-filtration and freeze-thaw cycle techniques to separate the (1,3)-β-D-glucans from broth of mycelium liquid culture of G. lucidum. The separation was based on the properties of the (1,3)-β-D-glucans having larger molecular weight than other polysaccharides and having high tendency to aggregate. A freeze-dried powder containing 3.6% of (1,3)-β-D-glucans was used as raw material for this study. The results indicated that ethanol fractional precipitation adjusting ethanol concentration at 40% was the most efficient way, having 68.3% of recovery, among mentioned methods to purify (1,3)-β-D-glucans from a hot-water extract. The purity of the fractioned polysaccharides was 93.2% on carbohydrate basis. Increasing ethanol concentration increased both recovered quantity of the polysaccharides and the glucans but decreased the content of (1,3)-β-D-glucans. The operations of ultra-filtration using 10 kDa molecular weight cutoff (MWCO) hollow fiber membrane and freeze-thaw cycle recovered 73.5% and 34.3% of the (1,3)-β-D-glucans, respectively; the contents of the glucans were 35.3% and 14.1% on carbohydrate basis, respectively. Combination of ultra-filtration and freeze-thaw cycle could significant increase the content of (1,3)-β-D-glucans up to 69.4% with slightly lower recovery, 65.3%.
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