碩士 / 國立成功大學 / 環境工程學系碩博士班 / 97 / In this research, algae suspensions, containing cyanobacteria (Microcystis aeruginosa) and green algae (Chodatella sp.), harvested from axenic cultures in the lab, are used to simulate the source water from eutrophic reservoirs. These suspensions were subjected to oxidation by either chlorine (NaOCl) or ozone. The effect of type of oxidants and dosages on the characteristics of extracellular polymeric substances (EPS) of algae was studied.
First, the soluble EPS from the original algal suspensions were extracted by centrifugation, and then characterized by NPDOC, UV254, protein and carbohydrate concentration, and also by fluorescence excitation-emission matrixs (EEMs) spectroscopy. The molecular size distribution of soluble EPS was analyzed by high performance size exclusion chromatography (HPSEC). The results show that, before oxidation, the molecular size distribution of soluble EPS of both algae species are dominated by smaller size group (＜ 1 KDa). Generally speaking, M. aeruginosa has higher EPS contents than that of Chodatella sp. However, the former has higher proportion of larger M.W. ( 10 KDa) and lower M.W. (1 KDa) compounds than that of the latter. According to EEM, the EPS of both algae species are dominated by aromatic protein-like. However, Chodatella sp. has higher proportion of soluble microbial by-product like, humic acid like, and fulvic acid like compounds than that of M. aeruginosa.
Both chlorine and ozone was found to change the fluorescence characteristic of soluble EPS of both algae. The major fluorophore type was changed from aromatic protein- like to fulvic acid-like after oxidation. For M. aeruginosa, that change occurred when chlorine and ozone dosages reached 0.39 and 0.12 mg/L, respectively; while the corresponding dosages for Chodatella sp were 7.7 and 0.17 mg/l, respectively. These results indicate that the soluble EPS of Chodatella sp were more insert to oxidation than that of M. aeruginosa. Concerning the change in molecular size distribution of soluble EPS, the results show that the shift of the distribution to larger M.W. group (＞10 kDa) after ozonation was occurred at low dosage for M. aeruginosa. However, similar phenomenon was not noticed for Chodatella sp.
| Identifer | oai:union.ndltd.org:TW/097NCKU5515038 |
| Date | January 2009 |
| Creators | YU-JHANG LIN, 林育彰 |
| Contributors | Hsuan-Hsien Yeh, 葉宣顯 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 101 |
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