Quantifying and identifying metabolically active iron- and sulfate-reducing bacteria in contaminated sediments

Kuk-Jeong (Kuki) Chin
Department of Biology, Georgia State University, Atlanta, GA 30303

The difficulty of measuring microbial activity in anaerobic environments and the
possibility that there may be a correspondence in transcript levels of genes for metabolic
processes and the rates of those processes have suggested that monitoring transcript
levels for key genes may provide an alternative method for assaying rates of metabolism.
We have demonstrated the utility of transcripts for dissimilatory (bi)sulfite reductase
(dsrA) genes and for Geobacteraceae citrate synthase (gltA) genes as molecular proxies
for sulfate- and Fe(III)-reducing prokaryotes in subsurface sediments and led to an
understanding of the metabolically-active prokaryotes participating in the corresponding
electron transport pathways. The objective of our ongoing research is to provide a
mechanistic understanding of the function and structure of microbial communities with a
high bioremediation potential in radionuclide- and/or petroleum-contaminated
environments.