| Summary: | 碩士 === 大仁科技大學 === 生物科技研究所 === 96 === Xylaria nigripes (Koltz.) Sacc., also known as Wu Ling Shen, is a high value medicinal fungus of family Xylariaceae. According to the traditional Chinese pharmacopoeia, it possesses the properties of diuretic, invigorating kidney and enhancing immune function, as well as improving insomnia, woman menstrual cycle and bleeding after giving birth. In order to develop the Xylaria nigripes industry, it is important to understand the conditions and technique for its large scale production. The present study aimed to examine the mycelial growth rate and production of three different Xylaria nigripes (XN-1, XN-2 and XN-3) isolates using liquid fermentation. In addition, their polysaccharides content and DPPH radical scavenging activity were also evaluated. Results showed that under the basic medium comprising K2HPO4、KH2PO4、MgSO4 • 7H2O 0.05%, the optimal cultured condition for XN-1 was glucose 2.5%, yeast extract 0.5 %, 30℃, shaking speed 250rpm, pH 8.0 in 7 days, of with the mycelium weight and polysaccharide content were 12.2±0.01g/L and 10.17±0.09% respectively. For XN-2, the best condition was fructose 2.5%, peptone 0.3%, 26℃, shaking rate 150 rpm, pH 7.0 in 8 days, with the mycelial weight and polysaccharide content 10.9±0.01 g/L and 10.22±0.06%, respectively. For XN-3, the optimal condition was corn powder 5%, soya bean powder 0.5%, 22℃, shaking rate 200rpm, pH 6.0 in 8 days, with the mycelial weight and polysaccharide content 11.3±0.01 g/L and 9.94±0.10%, respectively. Under this optimal condition , XN-1, XN-2 and XN-3 exhibitd a better mycelial growth and polysaccharide production than PDB. Extracts of these mycelium also showed a better DPPH radical scavenging activity than that of PDB culture. Take together, these results conclude that the growth rate and polysaccharide production of XN can be improved by optimizing the condition of liquid fermentation, which can also enhance the DPPH radical scavenging activity.
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