碩士 / 國立臺灣海洋大學 / 海洋生物研究所 / 102 / In this study, effect of UV and diesel oil on the production and composition of exopolysaccharides (EPS) and wax esters by the UV resistant oil degrading bacterium (Ochrobactrum tritice B32), yeast (Candida keelungensis SM22), and two microbial communities (UV12 and UV24) enriched from diesel oil were investigated. Effect of inoculum, medium composition (such as diesel oil concentration, carbon sources or nitrogen sources) and environmental factors (such as temperature, salinity, pH or UV radiation) on the yield and composition of the EPS were determined. Results showed that different carbon sources or nitrogen sources could change the composition (carbohydrate, protein, uronic acid, reducing sugar and lipid) and the emulsifying activity of EPS produced by the microorganisms. These EPSs were found to be completely soluble in distilled water but insoluble in chloroform, toluene and hexane. Maximum EPS production by UV12, UV24, SM22 and B32 were 16.1 mg/mL, 14.0 mg/mL, 15.6 mg/mL and 16.8 mg/mL, respectively.UV (A/B) radiation increased EPS production sharply (1.1-5.2 times) by these microorganisms. UV (A/B) radiation also changed composition of EPS produced by these microorganisms. These EPS were not toxic to Artemia salina nauplii.When testing their ability to remove diesel oil from the contaminated sediment, the results showed that UV radiation could increase marine diesel oil removal. Experimental groups removed 80~95% while the control removed only 71.9% TPH after 70 days inoculation.All the test microorganisms also produced wax esters. In most cases, higher concentration of oil (1-5%) produced higher concentration of wax esters (0.9-4.8 mg/mL). However, when oil concentration increased to 10-20%, wax ester production was not correlated to the oil concentration.The chemical nature and stability of the EPS suggest its potential application in bioremediation of marine environments. Their stability under diverse conditions, such as temperature, pH and salinity, also makes this biopolymer a versatile emulsifier for use in many food and pharmaceutical formulations.
| Identifer | oai:union.ndltd.org:TW/102NTOU5270001 |
| Date | January 2014 |
| Creators | Lu, Rou-Ying, 呂柔瑩 |
| Contributors | Liu, Shiu-Mei, 劉秀美 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 77 |
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