- 學位論文
由微生物生產功能性PHA及其結構分析
Structure Analysis of Functionality PHA Produced by Fermentation
摘要
本研究為利用Haloferax mediterranei菌株進行錐形瓶發酵實驗，探討培養基基質的改變對菌體生長和PHA累積量的影響，及含官能基之碳源饋料發酵對PHA結構之影響。實驗結果發現，以初始pH= 7.0之培養基進行培養，菌體生長狀況較佳，而以初始pH=6.5之培養基進行培養，其PHA的累積量較高。在高鹽濃度下，PHA累積量較低；在缺乏鉀離子的情況下，PHA累積量較高。初始glucose/YE之影響，其菌體量和PHA含量皆隨著glucose/YE的上升而遞增。KH2PO4添加濃度之探討，以培養基中添加0.1 % KH2PO4發酵所得菌體量最佳；但添加0.0125 % KH2PO4發酵生產之PHA含量最高。不同時間添加KH2PO4之結果，以培養基初始即添加KH2PO4發酵所得菌體量和PHA累積量皆最高。碳源饋料發酵和產物結構分析方面，以葡萄糖為碳源發酵生產之PHA為PHBV，其PHV約佔7-8 %；以olive oil、soybean oil、oleic acid、citronellyl acetate等碳源饋料發酵生產之PHA為PHBV，其PHV佔PHBV的比例分別為8-11 %，7-8 %，5-7 %和8 %。為知悉以有機溶劑溶解具官能基之碳源以為發酵基質之影響，另外於培養基中添加乙醇進行發酵，發現並不影響菌體的生長，而添加乙二醇則會導致菌體生長狀況較佳。
並列摘要
Effect of various substrates including some organics possessing functional groups on cell growth and accumulation of polyhydroxyalkanoate (PHA) were investigated using 250 mL shake flasks. The strain used was Haloferax mediterranei. It was found that the microorganism grew well at pH 7.0 and accumulation of PHA was higher at pH 6.5. Accumulation of PHA in the medium containing high concentration of NaCl tended to low and tended to high under the deficiency of K+. Cell mass concentration and PHA content increased with increase of glucose/yeast extract ratio. The effect of KH2PO4 concentration was remarkable. The highest cell mass concentration was attained at 0.1 % KH2PO4 and the highest PHA content was obtained at 0.0125 % KH2PO4. As for addition time of KH2PO4, the dosage at beginning of a fermentation resulted in the highest cell mass concentration and PHA accumulation. Introducing the functional group(s) into the structure of PHA is a target of this investigation. 7-8 % of PHV (polyhydroxyvalerate) was incorporated into the structure of PHA when the glucose was a sole carbon source. Some unsaturated fatty acids were employed to dosage to the culture medium expecting the incorporation of the functional group(s) included in them could be achieved. The percentages of PHV in PHBV produced by dosages of olive oil, soybean oil, oleic acid and citronellyl acetate were 8-11 %, 7-8 %, 5-7 % and 8 %, respectively. The effect of addition of the organic solvents which were used to solubilize the organics possessing the functional group(s) on cell growth was studied. The results showed that the addition of ethylene glycol kept cell growing well. On the other hand, ethanol did not exhibit an inhibitory effect on the cell growth.