Different chemical structure of polyhydroxyalkaoates produced from Haloferax mediterranei by using different hydrocarbon precursors

• Main Authors: Chih-Yung Chiang, 姜智雲
• Other Authors: Chen, C. Will
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/10972418072530914384

碩士 === 大同大學 === 生物工程學系(所) === 97 === In order to decrease the demand of petroleum-based plastic, therefore developing the substitive materials that could decompose naturally and are harmless to environments is becoming one of the most important green technologies. Extreme halophiles, Haloferax mediterranei, could live in the environment of high concentrations of NaCl, and not only could be cultured for long period of time without the risk of microbial contamination, but also produce biodegraded polyhydroxyalkanoates (PHA). The structures of most of PHA are hard and brittle materials composed mostly by 3-hydroxybutyrate (3HB) monomer. The increasing of 3-hydroxyvalerate (3HV) monmer within PHA structure could improve its elongation and toughness. In this research, we find when we use the glucose as the carbon source for cultivating H. mediterranei, we can only get PHA of 4.8 % 3HV. If using the agricultural wastes like ground bagasses as the carbon source to culture H. mediterranei , we still get PHA of low percentage (5.3 %) 3HV. By using glucose or soybean oil hydrolyte as the carbon sources and adding precursors of valerate (0.5 g/L) at cucultivation time of 34 hours can promote producing PHA of 26.0 % 3HV (in case of glucose) and 26.7 % 3HV (in case of soybean oil hydrolyte). By adding 1 g/L sodium valerate at cucultivation time of 34 hours can get PHA of 35.2 % 3HV (in case of glucose) and 36.5 % 3HV (in case of soybean oil hydrolyte). When adding mixture of valerate (0.5 g/L) and sodium valerate (1 g/L) as the precursors at cucultivation time of 34 hours, we can get 3HV of 37.4± 7.2 % (in case of glucose) ; we can get 3HV of 48.2±29.6 % (in case of soybean oil hydrolyte). In the study, we also find that sodium valerate can promote H. mediterranei growing. When increasing sodium valerate form 0.5 g/L to 8 g/L in the culture medium, we can get the maximum cell concentration of OD520nm form 11.3 to 33.1