Cometabolic biodegradation processes are potentially useful for the
bioremediation of hazardous waste sites. In this study the potential application of phenol-oxidizing
and nitrifying bacteria as "priming biocatalysts" was examined in the
degradation of polycyclic aromatic hydrocarbons (PAHs), aryl ethers, and aromatic
ethers. We observed that a phenol-oxidizing Pseudomonas strain cometabolically
degrades a range of 2- and 3-ringed PAHs. A sequencing batch reactor (SBR) was used to
overcome the competitive effects between two substrates and the SBR was evaluated as a
alternative technology to treat mixed contaminants including phenol and PAHs. We also
have demonstrated that the nitrifying bacterium Nitrosomonas europaea can
cometabolically degrade a wide range polycyclic aromatic hydrocarbons (PAHs), aryl
ethers and aromatic ethers including naphthalene, acenaphthene, diphenyl ether,
dibenzofuran, dibenzo-p-dioxin, and anisole. Our results indicated that all the compounds
are transformed by N. europaea and that several unusual reactions are involved in these
reactions. In the case of naphthalene oxidation, N. europaea generated predominantly 2-naphthol whereas other monooxygenases generate 1-naphthol as the major product. In the
case of dibenzofuran oxidation, 3-hydroxydibenzofuran initially accumulated in the
reaction medium and was then further transformed to 3-hydroxy nitrodibenzofuran in a
pH- and nitrite-dependent abiotic reaction. A similar abiotic transformation reaction also
was observed with other hydroxylated aryl ethers and PAHs. We also characterized the
role of AMO in the degradation of aromatic ethers. Our results indicated that aromatic
ethers including anisole were transformed by both 0-dealkylation or hydroxylation
reactions. This research has led to the development of a rapid colorimetric assay to detect
AMO activity. / Graduation date: 1998
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33803 |
| Date | 11 November 1997 |
| Creators | Chang, Soon Woong |
| Contributors | Williamson, Kenneth J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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