Degradation of Organic Complexing Agents by Halophilic Microorganisms in Brines

Abstract

The potential use of geologic salt beds as terminal repositories for nuclear waste has necessitated research on the interaction of the waste with indigenous microbiota. Microorganisms may affect actinide solubility by degrading organic complexing agents present in the waste. A halophilic bacterium and Archaea indigenous to a salt formation in New Mexico were examined for their ability to degrade acetate, oxalate, citrate, and ethylenediamine tetraacetate under aerobic conditions in low and high-magnesium brines. All complexing agents, except EDTA, were utilized, suggesting that microorganisms indigenous to such repositories can potentially play a beneficial role in mitigating actinide mobility.

Keywords:

• halophile
• brine
• organic complexing agent
• salt-based repository
• halite

Acknowledgments

This article not subject to US copyright law.

This developmental work was sponsored by the US Department of Energy Carlsbad Field Office (DOE-CBFO) and supports the ongoing recertification of the WIPP TRU repository program. The work was performed at the Carlsbad Environmental Monitoring and Research Center, operated by New Mexico State University. The authors wish to acknowledge Russ Patterson (DOE-CBFO) for program support and to thank Dr. Marian Borkowski for his helpful review of this work.