Pentachlorophenol (PCP) is a chloride-containing aromatic compound which is mostly used for preserving wood and leather, but still one can easily detect this compound present in the waste water generated by various industries such as petrifaction, oil-refining, and etc. PCP, due to its chemical property of being stable and highly toxic, would cause severe and irreparable environmental pollution once exposed to open air. This study is intended to explore the feasibility of dealing the problem of PCP with biodegradation. The examination results showed that, except for absorption, the suspension of contaminated soil (aerobic incubation), nonetheless, could effectively degrade PCP during a period of 90 days without the aid of any extra carbon source. (0.62 mg/L/day). The degradation rate was further greatly improved by adding sodium acetate, molasses, and sludge cake (sodium acetate added: 4.15 mg/L/day; molasses added: 1.05 mg/L/day; sludge cake added:0.83 mg /L/day). None of four experimental groups of aerobic sludge, anaerobic sludge, contaminated soil (anaerobic incubation), and Fe3+reaction could degrade PCP after 135 days, 174 days, 250 days, and 124 days, respectively, regardless of whether any sources of carbon were added or not. A bacterium which used PCP as the sole carbon source was isolated from the contaminated soil. After 16s rDNA sequence analysis, it had 98% degree of similarity to Pseudomonas mendocina and was designated as Pseudomonas mendocina NSYSU. The PCP (40 mg/L) degradation rate of Pseudomonas mendocina NSYSU was 9.33 mg/L/day, and the degradation rate would slow down as PCP concentration increased. At a PCP concentration of 320 mg/L, PCP degradation was completely inhibited, although an active population of Pseudomonas mendocina NSYSU was still present in these cultures. The study also indicated that the addition of various carbon sources such as sodium acetate and glucose did not facilitate the degradation of PCP with the degradation rate of 8.11 mg/L/day for sodium acetate, and that of 7.55 mg/L/day for glucose. Analysis from examining several environmental factors showed that the optimal condition for PCP degradation is that of 30¢J, pH6, and in the presence of oxygen. The end products of PCP degradation were detected by GC-MS. After 6 days of incubation, PCP was gradually disappeared and the metabolic intermediate product, acetic acid was detected. The chloride ion concentration also increased by 21.8 mg/L, which is approximately equal to the original total chloride content in PCP (66% of chloride content). In conclusion, PCP could be effectively and completely degraded by Pseudomonas mendocina NSYSU.

The purpose of this study is to isolate and identify the crude oil-degrading bacteria from oil polluted soil. Their physiological characteristics and oil-degrading capability were also studied. Eight polluted soil samples were taken from the Kaohsiung Refingery Factory of the Chinese Petroleum Corporation (CPC). The microbiota of the Kaohsiung refinery soil sample P37-2 (#6) could degrade crude oil from 2000 ppm to 572 ppm in 10 days. Bacteria in polluted soil samples were selected and isolated by minimal medium with 2000 ppm crude oil as the sole carbon source. Biochemical test, PCR-DGGE, and 16S DNA sequencing were used to identify and characterize the bacteria isolates. Three strains were identified as Pseudomonas aeruginosa (NSYSU-1-1), Acinetobacter sp. (NSYSU-4-1), and Pseudomonas sp. (NSYSU-7-1). These three strains and microbiota #6 were tested for their capability of degrading the total petroleum hydrocarbons (TPH). We found that microbiota #6 performed better than the other three bacterial strains in degrading the crude oil. In this study, we also found temperature was not the major factor of influcing the biodegradation; however, high oxygen concentration and providing nitrogen soure couled improve the biodegradation rate. Although both NSYSU-1-1 and NSYSU-7-1 are Pseudomonas strains, they performed different on degrading the oil. All strains tested could degrade the crude oil to a concentration below 1000 ppm to meet the government emission standard. The bacterial strains and techniques developed in this study provide a choice for future bioremediation of crude oil pollution.

Polycyclic aromatic hydrocarbons (PAHs) are compounds containing carbon and hydrogen atoms of fused benzene rings in linear, angular or cluster arrangements. These compounds have a large (negative) resonance energy, resulting in a thermodynamically stable structures. PAHs may also contain alkyl- and nitro-substituent groups. The complexity in these molecules can be generated by substituting the aromatic carbon atom with nitrogen, oxygen or sulfur, giving rise to heterocyclic PAHs.

Reproduction de : Thèse d'exercice : Médecine. Pneumologie : Nantes : 2008. / Bibliogr.

Zugl.: Berlin, Techn. Univ., Diss., 2009

Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : [25]-27).

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : 63-66).

Thesis (PhD)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Michael Franklin. Includes bibliographical references.

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : 85-91).

Thesis (M. Sc.)--University of Hong Kong, 1970. / Mimeographed.