Microbial Degradation Of Pentachlorophenol Research Articles

5512478 Genes and enzymes involved in the microbial degradation of pentachlorophenol

5512478 Genes and enzymes involved in the microbial degradation of pentachlorophenol

5364787 Genes and enzymes involved in the microbial degradation of penta chlorophenol : Orser Cindy S; Xun Luyin, Moscow, ID, United States - Idaho Research Foundation

5364787 Genes and enzymes involved in the microbial degradation of penta chlorophenol : Orser Cindy S; Xun Luyin, Moscow, ID, United States - Idaho Research Foundation

5364787 Genes and enzymes involved in the microbial degradation of pentachlorophenol : Orser Cindy S; Xun Luyin, Moscow, ID, United States - Idaho Research Foundation

5364787 Genes and enzymes involved in the microbial degradation of pentachlorophenol : Orser Cindy S; Xun Luyin, Moscow, ID, United States - Idaho Research Foundation

5364787 Genes and enzymes involved in the microbial degradation of pentachlorophenol : Orser Cindy S; Xun Luyin, Moscow, ID, United States - Idaho Research Foundation

5364787 Genes and enzymes involved in the microbial degradation of pentachlorophenol : Orser Cindy S; Xun Luyin, Moscow, ID, United States - Idaho Research Foundation

Microbial Degradation of Pentachlorophenol and Lindane in Laboratory-Scale Activated Sludge Reactors

The microbial degradation of pentachlorophenol (PCP) and lindane in the activated sludge process was studied. 14 steady-state experimental runs were performed in single-stage activated sludge reactors under various operating conditions. PCP and lindane mixed with three other model compounds were added to the feed as secondary substrate, with synthetic sewage as primary substrate. Reactor concentrations (dissolved) of the model compounds were in the range of 1-200 µg/l. For PCP, the biodegradation increased with increasing solids retention time SRT. This indicates that degradation takes place by catabolic growth of a specific fraction of the biomass. At SRT > 8 days the 1st order biodegradation rate constant was about 2.5 × 10−3 1/(mg MLSS day) at a temperature of 15°C. For lindane, the reverse relation was observed. Increased degradation was observed with increasing degradation of primary substrate. This indicates the presence of other mechanisms such as co-metabolism or probably reductive dechlorination. In relation to upgrading of wastewater treatment plants to biological nutrient removal, xenobiotic compounds behaving like PCP are expected to be increasingly degraded. For compounds behaving like lindane, co-metabolic activity can be stimulated in plug-flow reactors rather than CSTR, and anaerobic zones in the activated sludge process may play an important role for the degradation.

Biodegradation and photolysis of pentachlorophenol in artificial freshwater streams.

The biodegradation, photolysis, and adsorption of pentachlorophenol (PCP) in outdoor, aquatic environments were examined with man-made channels built by the U.S. Environmental Protection Agency at a field station on the Mississippi River near Monticello, Minn. Four channels were used, each channel being approximately 520 m long and receiving river water that flowed through the channels for about 10 h before reentering the river. The channels were dosed continuously during the summer of 1982 with various concentrations of PCP (approximately 0, 48, 144, and 432 micrograms/liter). We monitored the biotic and abiotic degradation of PCP in these channels for approximately 16 weeks. Photolysis of PCP was rapid at the water surface, but greatly attenuated with depth. Depending on sunlight conditions, photolysis accounted for a 5 to 28% decline in initial PCP concentration. Adsorption of PCP by sediment and uptake by biota accounted for less than 15% and probably less than 5% in unacclimated water. Microbial degradation of PCP became significant about 3 weeks after the initiation of dosing and eventually became the primary mechanism of PCP removal, accounting for a 26 to 46% (dose-dependent) decline in initial PCP. Most of the PCP-mineralizing microorganisms that developed in the channels were either attached to surfaces (e.g., rocks and macrophytes) or associated with surface sediments. Total bacterial numbers (direct microscopic counts) in the various channels were not affected significantly by PCP concentrations of micrograms per liter. Numerous strains of bacteria able to grow at the expense of PCP were isolated from the adapted channels. The experiments reported here will help predict the responses of flowing aquatic ecosystems to contamination by biocides such as pentachlorophenol.