Student Abstracts: Biology at INEEL

Characterization of an Unknown Strain of Paenibacillus glycanilyticus Isolated from an Acidic Radionuclide-Contaminated Aquifer. CEDRICK WHITAKER (Jackson State University, Jackson, MS 39203) DAVID E. CUMMINGS, PH.D (Idaho National Engineering & Environmental Laboratory, Idaho Falls, ID 83415).

Microbially mediated reduction and immobilization of contaminants plays a major role in bioremediation of large contamination sites such as the DOE Oak Ridge Reservation in Tennessee. Understanding the microbial diversity of such sites is the first important step in bioremediation. The focus of this research was strain A1 from a contaminated soil sample obtained at Oak Ridge Reservation and isolated by Alicia Olson at the Idaho National Engineering and Environmental Laboratory (INEEL). Following DNA extraction, the 16S rRNA gene was amplified, purified and sent to Washington State University where it was sequenced. The partial gene sequence was 99% (544/545) similar to Paenibacillus glycanilyticus strain DS-1 (AB042938). Our isolate, Paenibacillus glycanilyticus strain A1, was cultured in TSB medium in which it has an optimal growth temperature of 30oC with a range of 28-37oC, subdividing it as a mesophile. Its morphology is a bacillus, i.e., rod-shaped, with a Gram-positive cell wall. Although the contaminated well from which this strain came was at pH 4, A1 did not grow at pH 4, but had a pH optimum of 6-8. To discover the optimal carbon source for cell growth, strain A1 was incubated in a defined minimal medium with the following electron donors: lactate, glucose, glycerol, starch, or acetate. Acetate proved to be the best carbon source, supporting the most rapid growth and highest final cell densities. This culture of Paenibacillus glycanilyticus strain A1 may be one of the possible novel species that can immobilize contaminants such as uranium or technetium; in which case, adding Paenibacillus glycanilyticus strain A1 and acetate to a contaminated site could begin the regimen of bioremediation. Before this conclusion can be validated, further research such as determining the optimal pH for growth, and which electron acceptors (i.e., contaminants) this organism may reduce.