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Grantee Research Project Results

Grantee Research Project Results

Ecology and Evolution of Bacterial Remediation of Water Pollution: Changing Microbes in a Changing World

EPA Grant Number: FP917112
Title: Ecology and Evolution of Bacterial Remediation of Water Pollution: Changing Microbes in a Changing World
Investigators: Turner, Caroline Breen
Institution: Michigan State University
EPA Project Officer: Jones, Brandon
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010)
Research Category: Academic Fellowships , Fellowship - Water Quality: Hydrogeology and Surface Water

Description:

Objective:

The goal of my research is to study how evolutionary and ecological interactions affect the ability of bacteria to degrade novel compounds. What selection pressures shape the rates at which bacteria are able to consume new substances? How do ecological interactions such as competition and predation affect the ability of bacteria to effectively remove novel compounds from the environment?

Synopsis:

Humans produce many pollutants that are rare or absent in nature. Remarkably, bacteria have evolved that can degrade many of these contaminants. However, we lack understanding of the evolutionary and ecological factors that drive this process. This research will study bacteria that have evolved to consume a new compound. By measuring rates of consumption as the bacteria evolve under various conditions, this research will allow improved utilization of microbes for bioremediation of pollutants.

Approach:

This research will use as a model system a strain of Escherichia coli bacteria that evolved the ability to consume citrate, a compound that E. coli normally cannot metabolize aerobically. This trait evolved as part of a long-term evolution experiment in the laboratory and is an ideal system in which to study the evolution of a new metabolism because the availability of frozen populations throughout the experiment will allow measurement of changes in citrate metabolism over more than 10,000 generations of evolution. The second portion of the project will focus on further evolution experiments with citrate consumers in the presence and absence of competitors and phage (bacterial viruses) to determine how these factors can shape the evolution of resource use.

Expected Results:

Later generations of citrate-consuming E. coli are expected to evolve increased rates of citrate consumption and to draw citrate concentrations down to lower levels as compared to earlier generations of citrate consumers. It is also predicted that in the presence of competitors for other carbon sources, the citrate consumers will evolve a greater degree of specialization on citrate than in the absence of such competitors. Evolution in the presence of phage may decrease rates of citrate consumption due to decreased population sizes and/or trade-offs between viral resistance and citrate consumption rates.

Potential to Further Environmental/Human Health Protection:

Bioremediation by microbes is an important mechanism for the removal of harmful and toxic compounds from surface and groundwater. However, we understand little about the basic evolutionary and ecological factors that drive this process. A better understanding of these phenomena will allow scientists to improve prediction of degradation rates of pollutants and to better utilize the evolutionary potential of microbes for bioremediation of novel contaminants.

Supplemental Keywords:

water pollution, bioremediation, experimental evolution, ecology, E. coli,

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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