以搖瓶振盪及小型發酵槽培養,探討培養基組成及物理化學因子,對於靈芝多醣生成及生長形態變化的影響

Abstract

靈芝多醣能提高機體免疫功能,顯助增強腹腔巨噬細胞吞噬能力,促進 肝臟和骨髓核酸與蛋白質的生物合成,用於抗衰老治療慢性肝炎. 本 研究以搖瓶振盪及小型發酵槽浸漬培養靈芝來生產其胞外多醣,所採用之 菌株為Ganoderma lucidumRZ.在搖瓶振盪培養中,我們探討了起始碳源濃 度之高低,蛋白棟之存在,對靈芝浸漬發酵的影響.另外則以乳糖半取代之 高起始碳源濃度,看是否有效促進菌絲體的增長,經分析結果發現如下: 靈芝浸漬發酵培養過程中,隨著菌體量的增加,多醣會分泌出胞外,然而當 菌體進入生長停滯期,多醣仍有持續產生之趨勢.高起始葡萄糖濃度的 HCHN 及 HCLac 培養基,都有較高的產物比生成速率,含蛋白棟的氮源,有 助於菌體生長所需.高起始葡萄醣濃度,有助於多醣的合成.菌體在以熱水 萃取過後,也可以回收部份多醣. 在發酵槽培養的主要研究目的,為探 討一些物理化學因子(包括酸鹼環境及二氧化碳通氣)對於靈芝菌體發酵生 產多醣及菌體生長形態的影響.結果發現如下: 起始培養基 pH 值較高 的情形下,類酵母菌有較明顯的生長趨勢.在 pH 值維持在 4.5 的操作環 境下,有最高的比生長速率且產物比生成速率及產物生成速率,都大於其它 兩次批次發酵.含團塊菌絲的 pH 調控實驗中,菌體對於溶養量的需求,遠 大於沒有含團塊菌絲的無pH 調控.通入二養化碳所造成的酸性環境,會抑 制菌體的生長. The Production of extracellular by Ganoderma lucidumRZ carried out in shake flasks as well as in batch submerged fermentation was investigated in this study. In shake-flask experiments,the target polysaccharide was accumulated extracellularlyduring both the growth and stationary phases of the microorganism. Medium HCHN and HCLac with high initial glucose concentration resulted in high product concentration and highspecific productivity.Using peptone as nitrogen source was also shown advantageous for cell growth.After extracted by hot water,some intracellular glucan could also be recovered. During batch-wise fermentation cultivation,the yeast-like growth dominated the culture at high pH values.Under the culture condition of pH 4.5,the yeast-like growth was obviously inhibited whereas pellet and mycellium dominated the culture.Our results reveal that when pH was kept constant at 4.5,the largest specific growth rat was obtained.In addition,its product formation rate and the specific productivity were higher than those of the other controlled cultures.In the experiment ith pH control and pellet inoculation,the demand of dissolved oxygen for cells was extremely larger than that in the uncontrolled experiment.In our study,we also found that the acidic environment caused by purging carbon dioxide would inhibit the growth of the microorganism.