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Biodegradation of PAHs in Diesel Fuel by Candida viswanathii in Salty Environment

Taiwan is an island country. Therefore, it must depend on sea and air transport to communicate with other countried. Especially, the import and export of cargo rely on the sea transport. Nowadays, some ships still use diesel oil as fuel. During the transport, the ship is inevitable for leak, or accidents happening in marine environment. Therefore, in this research, through the man-made sifting way, we will sieve and purify the pure species bacteria, which can degrade the PAHs in diesel fuel floating on the sea surface to decrease its pollution to the marine environment.
In this research, eight species of pure bacteria will be sifted to purify. After primarily degrading experiment, we found that the second species of the bacteria performed the best degrading effect. After further identification, it was known that the second species of bacteria was yeast with name of Candida viswanathii. The bacteria were then used to in this study on biodegradation of PAHs in the diesel fuel. According to the experimental results, we found that bacteria could degrade diesel fuel. The OD value and total amount of the bacteria were found to be increased, but showed less degrading effect on PAHs in diesel fuel. However, in the experiment regarding the bacteria against single kind of PAHs, it showed excellent degrading effect on Naphthalene. When the initial concentration of Napthalene was controlled at 10 mg/L, the degrading rates were 0.3 and 0.24 mg/L-day respectively, in two separate experiments. Concerned with the degrading experiment against Anthracene, learned from the chromatography diagram it was observed that the concentration controlled at 10 and 5 mg/L, the production rate of Naphthalene were measured equal to 0.049 and 0.028 mg/L-day respectively. Thus, it was concluded that Anthracene can be degraded by the bacteria, but the degrading rate was slow, and the metabolite might be Naphthalene. As for the Flouranthene, the bacteria presented no degrading effect on it. It was concluded that the bacteria might not degrading ability toward four-ring or above PAHs.
In conclusion, it is quite difficult to use single species of bacteria to deal with highly-complicated organic. It is suggested that we should study more about the degrading character of every species of bacteria. After that, we can get better effect by using similar compound bacteria to deal with the PAHs in the diesel oil.
Date29 June 2003
CreatorsYu, Tsung-Lin
ContributorsMing-Shean Chou, Pear-Hsiu-Ping Lin, Lei Yang
Source SetsNSYSU Electronic Thesis and Dissertation Archive
Detected LanguageEnglish
Rightsunrestricted, Copyright information available at source archive

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