| Abstract: | 摘要豬苓（Polyporus umbellatu）是中藥上常用的一種藥用真菌。近年，對豬苓所含之多醣的分離純化以及藥理學與治療應用等研究，證實豬苓的多醣具有抗腫瘤、抗病毒、降血糖、降血脂等活性，具有發展作為新藥之潛力。如何人工液態培養豬苓，以供應逐漸增大的保健食品市場是很值得研究的重點。本研究主要是利用人工液態培養找出較適培養條件，並擴大於發酵槽培養，探討不同培養條件對豬苓菌絲體及豬苓多醣體產量之影響。豬苓在搖瓶實驗分別作較適培養基的探討，發現以3％的葡萄糖作為碳源及以0.5％的酵母萃取物作為氮源培養時，有較佳的多醣的產量，可獲得菌絲乾重3.37 mg/ml、胞外多醣1.43 mg/ml以及胞內多醣0.95 mg/ml的生產。當以5 公升氣泡塔式發酵槽經過七天培養期，以通氣量為1 vvm較有利於豬苓的培養，可得菌絲乾重7.02 mg/ml、胞外多醣1.62 mg/ml，以及胞內多醣1.04 mg/ml的產量，當以5公升攪拌式發酵槽培養則有菌絲乾重10.85 mg/ml、胞外多醣1.50 mg/ml及胞內多醣0.99 mg/ml。而進行饋料式發酵槽培養時，則有助於增加豬苓菌絲及多醣的生產；在氣泡塔式饋料培養菌絲乾重達8.13 mg/ml、胞外多醣達1.77 mg/ml及胞內多醣1.24 mg/ml的產量，而在攪拌式饋料時菌絲乾重11.87 mg/ml、胞外多醣1.65 mg/ml及胞內多醣1.14 mg/ml。此外，將發酵槽培養所得之豬苓多醣以膠體液相層析法分析其分子量，其中以攪拌式通氣量為0.5 vvm培養時，較高分子量，其胞外多醣分子量分佈範圍在1.8×105至2.1×106 Da之間，而胞內多醣分子量分佈範圍為3.5×106至1.5×107 Da之間；其次以攪拌式發酵槽通氣量1 vvm培養時，胞外多醣分子量分佈範圍在1.0×104至7.5×105 Da之間，而胞內多醣分子量分佈範圍在2.7×105至5.6×106 Da之間。胞內多醣的分子量都大於胞外者。
Abstract Polyporus umbellatus is a medicinal fungi, its sclerotium has long been used as traditional Chinese herb. The polysaccharide, a constituent of the P. umbellatus, have been reported to have antitumor, immunological enhancement, antidiabetic and anti-HIV effect. The growing demands of neutraceutical fungi on the food and pharmaceutical markets would encourage the research on the cultivation of P. umbellatus by fermentations. The objective of this experiment was to evaluate the effects of growth condition and environmental factors on the formation of polysaccharides by P. umbellatus in submerged culture fermentation.The results indicated that 3% glucose and 0.5% yeast extract in the culture medium were the most suitable carbon and nitrogen sources, respectively, for both mycelial biomass and polysaccharides production in the shake flask fermentation. It has 3.37 mg/ml mycelium dry weight, 1.43 mg/ml exo-polysaccharide(EPS) and 0.95 mg/ml intra-polysaccharide(IPS) in the broth. In the fermentor studies, aeration with 1 vvm favors the production of the polysaccharides of P. umbellatus by batch fermentation both in the 5 liter bubble column fermentor(BCF) and stirred tank fermentor(STF). Production for the 5 liter BCF was 7.02 mg/ml mycelium dry weight, 1.62 mg/ml EPS and 1.04 mg/ml IPS in 7 days, and for the 5 liter STF was 10.85 mg/ml, 1.50 mg/ml and 0.99 mg/ml, respectively. Fed-batch fermentation in BCF was 8.31 mg/ml mycelium dry weight, 1.77 mg/ml and 1.24 mg/ml, and fed-batch in STF was 11.87 mg/ml, 1.65 mg/ml and 1.14 mg/ml, respectively. The fed-batch culture increased the yield of fermentation. Molecule weight(MW) of the polysaccharide as analysed by gel permeation chromatography(GPC) was the highest in the STF with 0.5 vvm. The MW of the EPS and IPS was in the range of 1.8?105 to 2.1?106 Da and 3.5?106 to 1.5?107 Da, respectively. For STF at 1 vvm, the MW of EPS and IPS was in the range of 1.0?104 to 7.5?105 Da and 2.7?105 to 5.6?106 Da, respectively. The MW of the polysaccharide in STF 1 vvm is smaller than STF 0.5 vvm. The MW of all the IPS is larger than that of EPS. |
