| Summary: | 碩士 === 亞洲大學 === 生物科技學系碩士班 === 99 === Grifola frondosa is one kind of medical and edible fungus, and it has been found lots of functions such as: anti-tumor, strengthen the immune system, lowering blood glucose, blood pressure and cholesterol, and weight-loss and other anti-diabetic effects. The international biological and medical community has been highly paid attention to G. frondosa recently. Due to the traditional cultivation of G. frondosa from the inoculation to produce fruiting bodies which takes a long time, the fermentation technology to produce mycelium and polysaccharides can not only shorten the training time, but also increase the quality and the yield stably. For the above reasons, the three purposes of this study are as follows. (1) To investigate the best carbon and nitrogen source of the five strains of G. frondosa by solid-state culture. (2) To study the production effects of G. frondosa mycelium and polysaccharide by different rpm and different initial pH value of submerged culture. (3) To analyze total polyphenol and flavonoid content and fermentation DPPH radical scavenging ability of the fermentation broth of G. frondosa. The first part of experimental results showed that best carbon source and the nitrogen source for the mycelium growth of five strains G. frondosa after 20 days cultivation were as follows: the 4% fructose as the carbon source and the 2% corn steep powder as the nitrogen source caused the mycelium growth of T1 strain reached 40.17 mm; the 3% glucose and the 1.5% corn steep powder let the mycelium growth of T2 strain reached 42 mm; the 4% fructose and the 1.5% yeast extract urged the mycelium growth of BT strain reached 42.83 mm; the 4% glucose and the 1.5% corn steep powder caused the mycelium growth of D-4 strain reached 41 mm; the 4% glucose and the 1.5% corn steep powder caused the mycelium growth of 5-T strain reached 42 mm. The second part of the study was designed to investigate the different rpm and initial pH value on the impact of submerged culture of G. frondosa. According to the experimental results, All strains (T1, T2, BT, D-4 ,5-T) in rpm 150 under cultivation, the highest yield of polysaccharide were 2.82±0.56, 2.11±0.13, 3.24± 0.71, 2.85±0.39, 2.06±1.23 g/L, but the mycelium and the final pH of no significant impact of the change. Part of the initial pH value, T1, T2 and BT strains of G. frondosa, produced respectively the highest mycelial yields as 1.83 g/L, 4.18 g/L and 3.16 g/L when the initial pH value was 5.5. In addition, D- 4 and 5-T strains, produced the highest mycelial yields when the initial pH values were 6.5 (3.83 g/L) and 4.5 (3.14 g/L). Furthermore, the maximum polysaccharide production of G. frondosa T1, T2, BT and 5-T strains were 8.39, 7.57, 5.56 and 5.07 g/L when the initial pH was 4.5. The D-4 strain presented the highest yield of polysaccharides (7.07 g/L) when the initial pH was 6.5. The third part of the antioxidant ability experiments indicated that the fermentation broth of T2 strain contained the highest total polyphenols (29.75 mg/g) and flavonoids (1.20 mg/g) above other strains under the cultivation conditions of 3% fructose and 1.5% corn steep powder at initial pH of 6.5. Moreover, T1, T2, BT, D-4, and 5-T strains presented the highest ability of scavenging DPPH radicals were 53.70%, 46.88%, 57.81%, 48.68% and 55.54%. Especially, G. frondosa 5-T strain presented the best results of EC50 within five strains was 23.67 mg/mL under the fermentation conditions of 4% glucose, 1.5% corn steep powder and initial pH of 4.5. Summarize the above results, higher concentrations (4~3%) of glucose and fructose as the carbon resources were suitable for the mycelia growth of all five strains of G. frondosa. Lower concentrations of corn steep powder (2~1.5%) as nitrogen resources were suitable for all strains of G. frondosa. The initial pH values (the case of weak acid) of G. frondosa fermentation were not significantly affected the mycelium and polysaccharide productions, but they had a little impact on the antioxidant capacity of G. frondosa. The relationship between different carbon-nitrogen resources and antioxidant abilities; or between different surfactants such as vegetable oil and polysaccharide production of G. frondosa can be further investigated. Based on the achievement of this study, the related information can be provided to the farmers for the solid-state of cultivation and the submerged culture in five different strains of G. frondosa. In the future, the fermentation fluid of G. frondosa can be applied for the development of functional health products to increases the industrial utilities and to promote the additional values of G. frondosa.
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