以豆科為基質之靈芝液態培養物之水溶性多醣特徵

Abstract

液態培養是生產靈芝多醣的有效方式，其培養基組成與發酵條件對於菌絲的生長與多醣產量有顯著性的影響，利用豆科基質(黑豆與黃耆)對於靈芝多醣之含量與性質加以探討。在靈芝液態培養樣品來源，分別為三角瓶靜置培養、五公升試驗型發酵槽與兩百公升發酵槽三種。將這些不同來源的多醣中，以水溶性多醣濃度與具有(1,6)分支之(1,3)-β-D glucan為指標探討其多醣性質。在靜置培養樣品結果顯示，培養基中加入豆科發酵基質，明顯增加多醣與(1,3)-β-D glucan產量，未加豆科基質發酵之樣品，則未有明顯的改變。 由五公升試驗型發酵槽與兩百公升發酵槽的結果顯示，許多因子皆會影響多醣與其(1,3)-β-D glucan產量，而培養基中的豆科基質與溫度的影響 (由18到30℃的範圍)比通氣量的影響(由0.25到0.75vvm範圍)更明顯。其多醣含量與多醣中apparent (1,3)-β-D glucan最高可達到322 mg/dL與152 mg/dL，多醣中(1,3)-β-D glucan分子量分布大於85 k Da。在五公升試驗型發酵槽與兩百公升發酵槽中因生產裝置的不同導致其多醣與(1,3)-β-D glucan產量之最適條件也不同，明顯的影響多醣中(1,3)-β-D glucan的含量、分支度與分子量分布。這些實驗結果也指出靈芝中活性多醣性質對於在發酵過程中樣品的監控提供一品管之重要指標參考。

Liquid culture is an efficient method to produce Ganoderma lucidum polysaccharides. Culture media and cultivating conditions have significant effects on mycelium growth and polysaccharide production. The focus of this study was on the effects of using legumes (black soybean and Astragalus membranaceous Bunge) as media and cultivating conditions on producing yield and properties of G. lucidum polysaccharides. Liquid culture samples of G. lucidum mycelium were obtained from three sources: static cultures in flasks and five-liter experimental and two-hundred-liter fermentors. The concentration of water-soluble polysaccharide and (1, 3)-b-D-glucans having (1, 6)-b-glucosyl branches in culture were used as indices to study the differences of polysaccharides from different sources. The results of static culture experiments indicated that the using of combined legume medium significantly increased the production of polysaccharide and the (1, 3)-b-D-glucans but the using of individual legume as medium did not find significant changes. The analytical data from samples produced in five-liter experimental and two-hundred- liter fermentor indicated that multiple factors was affecting the production of polysaccharides and (1, 3)-b-D-glucans and the effects of using legume medium and temperature (in the range of 18°, 24° and 30°) were more significant than aeration (in the range of 0.25~0.75 vvm). The polysaccharide production could reach 322 mg/dL and (1, 3)-b-D-glucans could reach 152 mg/dL. The optimum condition for production polysaccharides and (1, 3)-b-D-glucans differed on five- and two-hundred-liter fermentors as producing apparatus. It was significantly affected by cultivating condition that of content the (1, 3)-b-D-glucan and its degree of branching in polysaccharides as well as molecular weight distribution of polysaccharides. The occurrence of the (1, 3)-b-D-glucans was exclusive in molecular weight larger than 85 kDa. The results indicated that affecting factors on polysaccharide production from G. lucidum mycelia were complicated quality monitoring was necessary for the processing.