| Summary: | 碩士 === 明新科技大學 === 化學工程研究所 === 97 === Phellinu igniarius, a basidiomycete belonging to the family Polyporaceae, has been well known as a medicinally potent mushroom due to its high anti-tumor activity. The polysaccharides from the fruiting body of this mushroom posses potential. Several mushrooms, belonging to the genus Phellinus such as Phellinus linteus and Phellinus igniarius, have been used as traditional medicines for the treatment of cardiovascular disease, tuberculosis, liver or heart diseases, bellyache, bloody gonorrhea, and diabetes. However, the limited production and market shortage have been attributed to the slow growth and the difficult collection of fruiting body as well as the rare nature resources. The problem can be solved through the effective approach of submerged culture to produce anti-tumor exo-polysaccharide (EPS) and antioxidant bioactive compounds of P. igniarius. In this study, lnfluence of culture pH on polysaccharide fermentation from Phellinus igniarius by submerged culture and its antioxidant properties were examined. P. igniarius culture at different pH ranging from pH 3 to 8 by submerged cultures was individually carried out in a 5-L fermentor and to increase production of exo-polysaccharide by regulating two-stage culture strategy (pH4→pH6). The experimental results exhibited that the maximum of mycelia production in stirred tank reactor was 7.37 mg mL-1 at pH 4. The maximum EPS production was 309.21 mg L-1 at pH 6. In order to improve the P. igniarius production, the two-stage culture strategy was used. The two-stage pH process (pH 4→pH 6) demonstrated a high biomass and EPS product with 8.28 mg L-1 and 415.51 mg L-1, respectively. In addition, the fermentation product extracts ( exo-polysaccharide (EPS) and intracellular polysaccharide (IPS) from mycelia ) showed high antioxidant activity, reducing powers, scavenging effects on 1,1-diphenol-2-picrylhydrazyl radicals, chelating effects and scavenging effects on superoxide anion. For antioxidant activity, the lowest EC50 value for EPS was 6.66 mg mL-1 at pH 6 and the lowest EC50 value for IPS was 14.70 mg mL-1 at pH 5. The lowest EC50 values for EPS on reducing powers were 2.26 mg mL-1 at pH 4. The lowest EC50 values for IPS were 0.29 mg mL-1at two-stage culture strategy. For scavenging effects on 1,1-diphenol-2-picrylhydrazyl radicals, the lowest EC50 values of EPS and IPS were 2.52 mg mL-1 and 14.16 mg mL-1 at two-stage culture strategy, respectively. For chelating effects, the lowest EC50 values of EPS and IPS were 1.42 mg mL-1 and 0.21 mg mL-1 at two-stage culture strategy. For scavenging effects on superoxide anion, the lowest EC50 values of EPS and IPS were 1.02 mg mL-1 and 2.04 mg mL-1 at two-stage culture strategy, respectively. The number molecular weights of exo-polysaccharides from the different pH were 4.15×105 ~2.02×106 (Da). At two-stage culture strategy, the number molecular weight of exo-polysaccharide were 2.61×106 (Da). The number molecular weights of intracellular polysaccharides from the different pH were 3.21×103 ~3.83×105 (Da). At two-stage culture strategy the number molecular weight of intracellular polysaccharide were 8.79×105 (Da).
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