Enrichment cultures of microorganisms separated from soil contaminated with pentachlorophenol and creosote were able to grow on and degrade phenol (300 mg 2-chlorophenol (100 mg L⁻¹), or 4-chlorophenol (100 mg L⁻¹) when added as the sole carbon source, but were unable to degrade 3-chlorophenol (100 mg L⁻¹) even after more than 127 days of incubation. Phenol biodegradation by enrichment cultures was completely inhibited by temperatures at or above 37 °C or phenol concentrations greater than 1,200 mg L⁻¹. Phenol degradation rates were reduced in the absence of an inorganic nitrogen source. Two species of gram-negative bacterial isolates from this soil degraded 300 mg L⁻¹ phenol in three to twelve days. A yeast isolate degraded 300 mg L⁻¹ phenol more quickly, in one to three days. No isolates were found that degraded any of the chlorinated compounds. Phenol biodegradation by the yeast was completely inhibited by substrate concentrations greater than 1,000 mg L⁻¹; it was partly inhibited by low dissolved-oxygen concentrations, substrate concentrations greater than 500 mg L⁻¹, and the presence of alternative carbon sources such as acetate or glucose. Acetate also inhibited yeast growth in the presence of phenol, while glucose stimulated it. The addition of yeast extract or thiamin stimulated yeast growth and phenol degradation by the yeast. In enrichment cultures, growth factors were provided to yeast by other microorganisms. Maximum rates of phenol degradation by yeast and enrichment cultures were comparable, often greater than 300 mg L⁻¹ phenol per day. Doubling times for yeast growing on phenol were generally from three to five hours. The rapid rates of growth and phenol degradation by isolates and enrichments suggest that biodegradation of phenol in the subsurface should not be substrate limited. Rather the transport of dissolved oxygen by advection/dispersion or vertical diffusion should limit phenol degradation by aerobic metabolic pathways in groundwater.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/191133 |
| Date | January 1988 |
| Creators | Pardieck, Daniel L. |
| Contributors | Bales, Roger C., Sinclair, Norval A., Gerba, Charles P., Arnold, Robert G., Evans, Daniel D. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Dissertation-Reproduction (electronic), text |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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