Anaeromyxobacter dehalogenans 2CP-C
Basic Facts, including why it is important and motivation behind sequencing

(i)Anaeromyxobacter dehalogenans efficiently reduces metals such as ferric iron, Fe(III), and oxidized uranium, U(VI) (He and Sanford, 2003).   Recent 16S rRNA gene-based studies with subsurface materials collected from the uranium-contaminated U.S. DOE-NABIR Field Research Center (FRC) at Oak Ridge, Tennessee suggested that Anaeromyxobacter species are key players in metal reduction at these sites (Kostka et al. 2002; Kostka et al., 2003).   Isolation efforts in Dr. Sanford's laboratory demonstrated that Anaeromyxobacter populations are widely distributed in the environment (Sanford et al., 2002), an observation supported by findings of other groups (Coates et al., 2002; Treude et al., 2003).   Drs. Löffler and Sanford were recently awarded a 3-year DOE grant through the NABIR program to study U(VI) reduction by Anaeromyxobacter populations, and to expand our understanding of the microbially-catalyzed metal reduction process.  

(ii) Anaeromyxobacter dehalogenans utilizes halogenated compounds, such as 2-chlorophenol, 2,6-dichlorophenol, 2,5-dichlorophenol, and 2-bromophenol, as growth-supporting electron acceptors (halorespiration) (Löffler et al. 1999; Sanford et al., 2002; He and Sanford, 2002; He 2003).   Chlorinated compounds are abundant pollutants at DOE and DOD sites, and tools for enhanced bioremediation are needed and are under current development.   The genome sequences of two relevant reductively dechlorinating populations, Dehalococcoides ethenogenes ( Chloroflexi group) and Desulfitobacterium hafniense ( Clostridia group), have been obtained by The Institute for Genomic Research (TIGR, and the DOE Joint Genome Institute, JGI (, respectively.   Anaeromyxobacter dehalogenans is a delta-Proteobacterium, and sequencing its genome would provide relevant information regarding reductive dehalogenase genes and the organization of reductive dehalogenase operons.   Such information is critical for the design of nucleic acid-based tools to detect, monitor and quantify functional genes involved in reductive dechlorination processes at contaminated sites.   Further, this information will allow comprehensive design strategies for robust quantitative and qualitative approaches aimed at evaluating and monitoring the reductively dechlorinating community at sites impacted with halogenated compounds, including chlorinated solvents.   Furthermore, reductive dehalogenases comprise a novel class of enzymes with a unique, but so far poorly understood, mode of catalysis.   The genomic information from A. dehalogenans would add to our understanding of these novel catalytic proteins, and could lead to innovative biotechnological applications.  

(iii) Anaeromyxobacter dehalogenans exhibits metabolic versatility, and grows under a variety of redox conditions.   Oxidized metal species such as U(VI) and Fe(III) (including ferric oxyhydroxide), anthraquinone disulfonate (AQDS), halogenated phenols, oxygen, nitrate, nitrite, and fumarate are used in terminal electron accepting processes (TEAPs) (Cole et al., 1994; Sanford et al., 2002; He and Sanford, 2003; Treude et al., 2003).   Further, Anaeromyxobacter dehalogenans demonstrates great electron donor versatility, and couples electron acceptor reduction to the oxidation of a variety of compounds including formate, hydrogen, acetate, succinate, pyruvate, and glucose.  

(iv) Anaeromyxobacter dehalogenans is a robust and competitive organism under environmental conditions.   A. dehalogenans is a promising candidate for bioremediation because it is a productive dechlorinator and a metal reducer under environmentally relevant conditions (e.g., fluctuating redox conditions, presence of competing electron acceptors).   A. dehalogenans strain 2CP-C is a facultative organism and is not affected by changing redox conditions (e.g., influx of oxygenated groundwater), and is active over a pH range of 6-8.5.   Furthermore, A. dehalogenans tolerates high concentrations of reduced products such as phenol or ammonium, respectively (He and Sanford, 2003; He and Sanford 2004).   In fact, Anaeromyxobacter species were found to be the predominant metal reducing populations at uranium-contaminated DOE NABIR sites that are characterized by changing redox conditions and low pH (Kostka et al. 2002; Kostka et al., 2003).

A feature that distinguishes A. dehalogenans from other reductively dechlorinating and metal-reducing populations is this organism's ability to both use acetate and hydrogen as a source of reducing equivalents.   Biostimulation of anaerobic processes typically aims at supplying the populations of interest with reducing equivalents needed to reduce the contaminants.   Since all approaches to increase the hydrogen flux will also increase the flux of acetate and vice versa (He et al. 2002), the process will be most efficiently stimulated if the key population(s) utilizes either electron donor.