| Summary: | 碩士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 92 === 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.
|
|---|
