Geobacter sp. Strain SZ
   
   
 

Geobacter lovleyi sp. nov. strain SZ was isolated from noncontaminated creek sediment based on its ability to derive energy from acetate oxidation coupled to tetrachloroethene (PCE)-to-cis-1,2-dichloroethene (cis-DCE) dechlorination (i.e., chlororespiration).

Geobacter lovleyi is a rod-shaped, motile, gram-negative, anaerobic delta-proteobacterium and belongs to a distinct, dechlorinating clade within the Geobacter group.  Strain SZ is the first Geobacter isolate capable of reductively dechlorinating the priority pollutant PCE, and shares features characteristic for members of the family Geobacteraceae.  For example, strain SZ uses acetate and hydrogen as electron donors and metabolically reduces a variety of electron acceptors, including oxidized metals, radionuclides (e.g., hexavalent uranium) and nitrate.  Remarkably, strain SZ reduces hexavalent uranium and PCE simultaneously, suggesting that SZ-type organisms have desirable characteristics for mixed waste site bioremediation. 


Specific16S rRNA gene-targeted PCR detected strain SZ-like amplicons at several chlorinated solvent sites and the uranium-contaminated Integrated Field-Scale Subsurface Research Challenge (IFC) site in Oak Ridge, TN (FRC site).  Further, a strain SZ-like bacterium was detected in the bioaugmentation consortium KB-1, suggesting that members of the dechlorinating Geobacter clade play relevant roles in bioremediation. 


Geobacter lovleyi was named to recognize the contributions of Derek R. Lovley to our understanding of microbial metal and radionuclide reduction.

 

References:

Sung, Y., K. E. Fletcher, K. M. Ritalahti, R. P. Apkarian, N. Ramos-Hernández, R. A. Sanford, N. M. Mesbah, and F. E. Löffler. 2006. Geobacter lovleyi strain SZ sp. nov., a novel metal-reducing and tetrachloroethene (PCE)-dechlorinating bacterium. Appl. Environ. Microbiol. 72:2775-2782.

Amos, B. K., Y. Sung, K. E. Fletcher, T. J. Gentry, W.-M. Wu, C. S. Criddle, J. Zhou, and F. E. Löffler. 2007. Detection and quantification of Geobacter lovleyi strain SZ: implications for bioremediation at tetrachloroethene- (PCE-) and uranium-impacted sites. Appl. Environ. Microbiol. 73:6898-6904.

Sanford, R. A., Q. Wu, Q., Y. Sung, S. H. Thomas, B. K. Amos, E. K. Prince, and F. E. Löffler. 2007. Hexavalent uranium supports growth of Anaeromyxobacter dehalogenans and Geobacter spp. with lower than predicted biomass yields. Environ. Microbiol. 9:2885-2893.

Duhamel, M., and E. A. Edwards. 2007. Growth and yields of dechlorinators, acetogens, and methanogens during reductive dechlorination of chlorinated ethenes and dihaloelimination of 1,2-dichloroethane. Environ. Sci. Technol. 41:2303–2310.