碩士 / 國立臺灣大學 / 農業化學研究所 / 91 / Since the increasing bacterial resistance abilities to antibiotics observed, more efforts were reported about finding novel antibacterial compounds from plants. At present, the antibacterial researches related to algae are usually about cyanobacteria and marine algae, and it is little about microalgae. In this study, we try to find new biologically active substances from microalgae.
The experiment is composed of three parts, the first is screening the antibacterial activities from forty strains of microalgae, and then choose the microalga which has the remarkable inhibition activity to go on the next part experiment. Eventually, we choose Chlorella pyrenoidosa C-10 for further experiments. Among the bacteria we test, the Gram-positive bacteria are more sensitive to microalgal extracts than Gram-negative bacteria.
The second part is to assay the antibacterial activity and some characters of C. pyrenoidosa extracts. The MICs of the extract to B. subtilis and B.cereus are 78.2 and 39.1 μg / mL, respectively. To kill Bacillus subtilis and Bacillus cereus needs 312.5 and 156.3μg dried weight of the microalga per milliliter, respectively. The extract is heat stable, because its activity does not decrease after being heated in 100℃ for 90 minutes. Using the scanning electronic microscope to observe the morphology of bacteria which are treated with microalgal extract, we find that the surface of the cell is rough.
The latest part of the experiment is to purify and identify the antibacterial compounds of C. pyrenoidosa. After passing the gelfiltration chromatographic column, collecting the fractions with antibacterial activity to analyze by high-performance liquid chromatography. The molecular weight of the antibacterial compound is about 1.2 kDa.
| Identifer | oai:union.ndltd.org:TW/091NTU00406069 |
| Date | January 2003 |
| Creators | Yu-Shan Lai, 賴玉珊 |
| Contributors | Liang-Ping Lin, 林良平 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 93 |
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