백영고 버섯의 최적 배양 및 생물활성에 관한 연구

Abstract

The purposes of this study were to determine the optimal culture conditions for mycelial growth and exo-polysaccharide production in liquid culture and test the biological activities of Pleurotus nebrodensis Inzenga. The optimal temperature and pH for mycelial growth and exo-polysaccharide production were 25？？ and a range of 6.5 to 7.0, respectively. The optimal inoculum age and volume percent were 7 days and 5%(w/v), respectively. Among the various carbon sources tested, glucose was the best carbon source. The maximum mycelial growth and exo-polysaccharide production were obtained when glucose concentration was 5%. The best nitrogen sources were polypeptone and yeast extract, respectively. Especially, in the case of the mixture of polypeptone (0.8%) and yeast extract (1.0%), the exo-polysaccharide production was higher than that of sole polypeptone or yeast extract. K2HPO4 0.12% (w/v) and MgSO4․7H2O 0.12% (w/v) were the most effective inorganic salts for mycelial growth and exo-polysaccharide production. Using optimum culture conditions in flask, the exo-polysaccharide production after 10 days of culture with a jar fermentor containing the optimized medium were 3.85 g/L, which was 1.5 fold higher than that of basal conditions. Using optimum culture conditions in flasks, the effects of aeration on mycelial growth and exo-polysaccharide production were investigated in 5L air bubble bioreactor. When 1.0-2.0vvm of aeration was used, the maximum exo-polysaccharide production after 12 days of culture was obtained 3.32 g/L, which was 1.7 fold higher than that of basal conditions. To investigate the antioxidant activities of P. nebrodensis Inzenga extracts, the DPPH scavenging rate, superoxide anion radical scavenging rate, linoleic acid scavenging rate, and nitric oxide production were determined in vitro. When the fruit body extract concentration was increased from 150 ug/mL to 1000 ug/mL, the DPPH scavenging rate was increased from 8.2% to 42.3%. However, it was not increased more than 1200 ug/mL. The linoleic acid scavenging rate of the fruit body extract was increased from 48% to 82% when the incubation time was increased from 6 hr to 22 hr. However, the incubation time was increased from 27 hr to 56 hr, it was decreased by 62%, which was a few higher than that of BHT. When the fruit body extract concentration was increased from 31 ug/mL to 63 ug/mL, the inhibition of nitric oxide production increased from 9.6% to 31%. The effects of decoctions prepared from P. nebrodensis Inzenga fruit body (PNIFB) on glutathione production, glutathione peroxidase, catalase, alcohol dehydrogenase, and acetaldehyde dehydrogenase activities in rat liver after chronic ethanol intake for 14 days were studied. When the decoctions prepared from PNIFB was added, the glutathione concentration was 13.5 uM/g of liver, which was about 2.2 fold higher than that of control. The activities of GSH-peroxidase, catalase, and alcohol dehydrogenase by adding the decoctions prepared from PNIFB were 4.1 U/ mg of protein, 121.3 KU/ mg of protein, and 2.1 mU/ mg of protein, respectively, which were similar to those of control. In the case of acetaldehyde dehydrogenase activity, it was 9.0 mU/ mg of protein, which about 80% was increased when compared to control In order to compare the hot water and methanol extract of P. nebrodensis Inzenga on the antitumor activities, various cancer cells were examined. The hot water extract concentration was increased from 125 ug/mL to 500 ug/mL the viability of Law 264.7 cell was decreased by about 60%. On the other hand, in the case of methanol extract, when it was increased from 63 ug/mL to 500 ug/mL the viability of Law 264.7 cell was decreased by about 45%. When the methanol extract concentration was increased from 250 ug/mL to 500 ug/mL, the viability of HEL299 cell was decreased by about 87%. On the other hand, in the case of the hot water extract, when it was increased from 63 ug/mL to 500 ug/mL, the viability of HEL299 cell was decreased by about 38%. For selecting the best extract solvents on the nitrite scavenging ratio, various solvents were used. When the diethyl ether extract of PNIFB was used, the maximum nitrite scavenging ratio was obtained, 28.1%. The maximum nitrite scavenging ratio was 40.1% when pH of PNIFB extract was 1.5. However, when pH of extract of PNIFB was increased from 3.0 to 6.0, it was decreased from 34.2% to 2.3%. In the case of PNIM, it was also affected by high pH.