Genetic Engineering of a Radiation-Resistant Bacterium for Biodegradation of Mixed WasteEPA Grant Number: U915322
Title: Genetic Engineering of a Radiation-Resistant Bacterium for Biodegradation of Mixed Waste
Investigators: Rothfuss, Heather M.
Institution: University of Washington
EPA Project Officer: Carleton, James N
Project Period: December 1, 1998 through December 1, 2001
Project Amount: $85,112
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Chemical Engineering
The objectives of this research project are to: (1) clone biodegradative pathways into the highly radiation-resistant bacterium Deinococcus radiodurans that will allow for degradation of organopollutants in the presence of radionuclides; and (2) explore the degradative capability of recombinant strains in mixed wastes.
Organisms that have the ability to degrade a broad spectrum of organics or convert them to nontoxic intermediates are ubiquitous in nature. Several organisms that can remediate heavy metals or protect themselves from being harmed by heavy metals also have been isolated. Many of the enzymes implicated in these abilities have been isolated and genetically characterized. However, in the presence of moderate- to high-level ionizing radiation, most organisms die or mutate because of the inability to quickly and correctly repair strand breaks caused by the radiation. The nonpathogenic bacterium D. radiodurans is an exception. The Deinococci have a very quick and accurate DNA repair system, can withstand ionizing radiation doses in the 5 Mrad range, and show no loss of viability at 500 krad. However, Deinococci do not appear to have a natural ability to degrade toxic organics. In this research project, our approach is to select enzymes that have the potential to allow D. radiodurans to attack organics of concern, to clone the genes encoding these enzymes into the chromosome of the bacterium, and to evaluate the level of expression, the stability, and the effect of the genes on D. radiodurans. This information will be used to formulate possible treatment strategies using the recombinant bacterium.