Tommy Joe Phelps

Activities in our laboratory focus on investigating metabolism, metal reduction, and the survival of thermophilic microorganisms isolated from deep subsurface environments. The objective is to provide a knowledge base from which to evaluate the potentialof deep subsurface bacteria to alter or mitigate wastes. We and our collaborators have examined subsurface environments that are >2500 meters beneath the land surface and have in situ temperatures of 20 to >70 degrees Celsius. Fermentative and metal-reducing microorganisms that appear distinct from known taxa have been isolated from these deep subsurface formations. Thermophilic metal-reducing anaerobes isolated from >2-kilometer depths in the Taylorsville Triassic Basin were compatible with the geologicsetting from which they were derived. They metabolize, grow, and survive at 70 degrees Celsius with an alkaline pH of 7.5-8.5 under brackish conditions. Furthermore, these unusual microorganisms tolerate brines containing 0.5-5% salt, and they reduce iron, manganese, and uranium when using carbohydrates or volatile fatty acids as an energy source. Investigations also focus on the ability of these microorganisms, which were hydrologically and geologically isolated for millions of years, to survive under in situ temperatures and pressures and low nutrient levels. The metabolic and physiologic characteristics of subsurface microorganisms and the geochemical features that constrain microbial abundance and activities in subsurface environments have been documented. Procedures developed through these studies have been implemented by DOE bioremediation demonstration projects and by environmental consulting firms.

Working Group Coordinator for Analyses of the Taylorsville Triassic Basin, Exploratory Origins Research, DOE/OHER Subsurface Science Program (SSP);Participant in Aseptic Drilling and Sample Handling Workshops as technology transfer efforts of the DOE/OHER SSP;Convener of DOE/OHER SSP workshops concerning analyses of the Taylorsville Triassic Basin samples ;Member of the DOE/OTD In-Situ Treatment Technical Support Group;Editorial Board for the J. Microbiol. Methods and a reviewer of manuscripts for several additional journals;Participant in Task Summary Group for Westinghouse Savannah River Site Integrated TCE Demonstration; Drilling Technology Steering Committee member and evaluation workshop attendee for the Microbiology of Subsurface Environments Program, DOE/OHER ;Invited participant to microbially facilitated corrosion, biomass fermentation and methanotrophic remediation workshops of the Gas Research Institute;supported and trained several technicians and served on graduate committees of students;Certificate of Appreciation, U.S. Dept. of Energy, 1991;Certificate of Recognition, Idaho National Eng. Lab., 1990