The following description comes mainly from Margulis and Schwartz (1998), Barnes (1984), Brock et al. (1994), and Tudge (2000).  
I. SYNONYMS: δ-proteobacteria, sulfate-reducing bacteria, bdellovibrios, and the gliding bacteria.  


A. Structure

Cell Form: Variable; rods, cocci, spirals or irregularly lobed.

Cell Wall: Gram-.

Motility: Non-motile or motile, the myxobacteria move by gliding over surfaces.

B. Physiology

O2 Tolerance: Strice anaerobes or aerobes.  No facultatively anaerobic taxa.

Substrates: They metabolize simple to complex organic compounds as heterotrophs.  

Products: Terminal electron acceptors include Oxygen (for the aerobes) to sulfur, sulfate and small organics.  Thus, the anoxic taxa typically reduce sulfate to a variety of sulfur compounds.  Almost all metabolize organic sources to carbon dioxide.

C. Other: Very diverse group of bacteria.

D. Ecology: Free-living in soils and aquatic sediments.



Black, J. G. 2002. Microbiology, Principles and Explorations. 5th ed. John Wiley and Sons, Inc. New York.

Brock, T. D., M.T. Madigan, J.M. Martinko, and J. Parker. 1994. Biology of Microorganisms. 7th ed. Prentice Hall. Englewood Cliffs, NJ.

Emerson, D., J. A. Rentz, T. G. Lilburn, R. E. Davis, H. Aldrich, C. Chan, and C. L. Moyer. 2007. A novel lineage of Proteobacteria involved in formation of marine Fe-oxidizing microbial mat communities. PLoS ONE. 2007 (8): e667. http://www.plosone.org

Gao, B. and R. S. Gupta. 2007. Phylogenetic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis. BMC Genomics. 8:86. http://www.biomedcentral.com/1471-2164/8/86.

Garrity, G. M., M. Winters, and D. Searles. 2001. Bergey's manual of systematic bacteriology. 2nd ed. Springer-Verlag. New York.

Garrity, G. M., J. A. Bell, and T. G. Lilburn. 2003. Taxonomic Outline of the Prokaryotes. Bergey's Manual of Systematic Bacteriology. 2nd edition. Release 4.0. Springer-Verlag. New York.  pp. 1-397.

Margulis, L. and K. Schwartz. 1988. Five kingdoms, an illustrated guide to the phyla of life on earth. 2nd Edition. W. H. Freeman and Co.  New York.

Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3nd Edition. W. H. Freeman and Co.  New York.

Stackebrandt, E., R. G. E. Murray, and H. G. Trüper. 1988. Proteobacteria classis nov., a name for the phylogenetic taxon that includes the "Purple Bacteria and Their Relatives". International Journal of Systematic Bacteriology. 38(3):  321-325.

Tudge, C. 2000. The Variety of Life, A Survey and a Celebration of all the Creatures That Have Ever Lived. Oxford University Press. New York.

Williams, K. P., B. W. Sobral, and A. W. Dickerman. 2007. A robust species tree for the Alphaproteobacteria. Journal of Bacteriology. 189(13): 4578-4586. 

Woese, C. R. and G. E. Fox. 1977. Phylogenetic structure of the prokaryotic domain: the primary kingdoms. Proceedings of the National Academy of Sciences USA . 74:5088-5090.

Woese, C. R., O. Kandler, and M. L. Wheelis. 1990. Towards a natural system of organisms: Proposal for the domains Archaea, Bacteria, and Eucarya. Proc. Natl. Acad. Sci. USA. 87: 4576-4579.


By Jack R. Holt.  Last revised: 02/18/2013