| Summary: | 碩士 === 東海大學 === 食品科學系 === 100 === Three solid substrates (adlay, black bean, and oat) were used to study their effect on the mycelial growth of Phellinus linteus during solid-state fermentation (30°C/20days). The oat was chosen as the most suitable substrate to investigate the optimal solid- state culturing conditions for production of polysaccharide and mycelial biomass, and to compare the bioactivity（antibacterial, antioxidant and antitumor activities）of hot-water and ethanolic extracts from solid-state culture and submerged culture by this strain.
Results showed that the optimal factors of solid-state culture were : incubation temperature of 30℃, water supplementation of 60% (v/w), inoculum volume of 3ml, fructose at 1% (w/w), yeast extract at 1% (w/w), folic acid at 0.3% (w/w), NaCl at 0.1% (w/w) and initial pH of 6.0. Under this optimized culturing condition, yields of polysaccharide (61.37 mg/g) and mycelial biomass（705.30 mg/g）obtained on the 12th day of incubation increased 1.63 and 1.35 times, respectively, as compared with those（45.48 mg/g and 432.30 mg/g, respectively）from basal medium.
Higher molecular weight (4.54×104Da) and relative β-(1→3)-D-glucan content (29.09 μg/ml LE) of polysaccharide were observed from Phellinus-fermented oat, as compared with those from oat substrate and submerged culture using air lift fermentor.
Both hot-water and ethanolic extracts from oats substrate, Phellinus-fermented oat and submerged culture demonstrated no antibacterial activities against the six bacterial strains (Bacillus cereus BCRC 10250, Escherichia coli BCRC 10239, Listeria monocytogene BCRC 14845, Pseudomonas aeruginosa BCRC 10261, Staphylococcus aureus BCRC 10451 and Salmonella typhimurium BCRC 10241) tested.
The hot-water extract from Phellinus-fermented oat had the highest DPPH scavenging effect (IC50＝1.23 mg/ml), chelating ability on ferrous ion (IC50＝5.26 mg/ml) , reducing power (IC50＝1.18m g/ml) and total antioxidant capacity (IC50＝0.89 mg/ml) among all extracts.
All hot-water extracts showed higher anti-tumor activity than ethanolic extracts, with the hot-water extract from Phellinus-fermented oat possessed the highest anti-tumor activity. After treated with hot-water extract from Phellinus-fermented oat (1000μg/ml, 5% CO2/37℃/48hr), viabilities of lung-cancer cells (A-549), breast-cancer cells (MCF-7) and liver-cancer cells (HepG2) were 46.29%, 55.75% and 63.33%, respectively, and were significantly (P＜0.05) lower than those of all other extracts.
In conclusion, Phellinus-fermented oat possessed polysaccharide with higher molecular weight and relative β-(1→3)-D-glucan content than those of submerged culture and unfermented oat substrate. Extracts from Phellinus-fermented oat showed better bioactivity than those from submerged culture. Among the extracts, hot-water extract had higher bioactivity than ethanolic extracts.
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