The toxic effects of degrading the chlorinated hydrocarbons trichloroethylene (TCE), chloroform (CF) and cis-1,2-dichloroethylene (cis-1,2-DCE) were studied in the bacterium Nitrosomonas europaea. N europaea is an ammonia-oxidizing bacterium that obtains all of its energy from the oxidation of ammonia to nitrite. This metabolic process involves two enzymes, ammonia monooxygenase (AMO)...
Polychlorinated dibenzo-p-dioxins (PCDD's) and
dibenzofurans (PCDF's) are environmental pollutants associated with the production and use of a number of industrial
chemicals. In addition, PCDD's and PCDF's are produced
during low temperature combustion of wastes containing
polyvinylchloride (PVC), chlorophenols, and a number of
other chemical precursors.
A significant source of environmental...
Mycobacterium vaccae JOB5 and Graphium sp. were studied to evaluate their ability to cometabolize methyl tert-butyl ether (MTBE) and its metabolites after growth on two different alkanes, propane and iso-pentane. Both cultures were capable of cometabolizing MTBE and the metabolites, tert-butyl formate (TBF) and tert-butyl alcohol (TBA). MTBE, TBF, and...
Chlorinated phenols are toxic compounds and often released into natural
environments from improper disposal or non-point sources. One important factor in
assessing the environmental fate and transport is the rates of microbial degradation in
soils and natural waters. In this study, eight chlorophenols (4-chlorophenol (4-CP),
2,4-dichlorophenol (2,4-DCP), 3,4-dichlorophenol (3,4-DCP), 3,5-dichlorophenol...
Trace metals in the aquatic environment are generally concentrated
on the surface of solid geochemical phases which eventually become incorporated
into estuarine and marine sediments. The mechanism of trace
metal concentration is believed to be adsorption with various geochemical
phases such as hydrous metal oxides, clays, and organic matter.
Metals...
Cometabolic biodegradation processes, important for bioremediation of hazardous waste sites, are not well understood and have not been modeled thoroughly. Toxic effects and bacterial responses to toxicity may change intracellular enzyme levels, rendering traditional enzyme kinetics models inappropriate. This document presents a novel cometabolic enzyme kinetics model that incorporates enzyme...
This qualitative study examined the influence of the 2011 Oregon Writing Project (OWP) Summer Institute (SI) on the professional development of six teachers in the following ways:
1. The development of case descriptions of teachers' personal and professional backgrounds relevant to their teaching of writing.
2. An examination of the...
Batch sorption tests were conducted using 3,4-DCP and cellulose triacetate as the sorbate/sorbent pair. Sorbate concentrations
in the liquid were sampled with time and analyzed by electron
capture detector gas chromatography. Sorption was found to be a two
stage process characterized by a rapid initial uptake followed by a
extended...