Thiobacillus

A Microbial Biorealm page on the genus Thiobacillus

Thiobacillus ferrooxidans. Jim Horan, "Acid Mine Drainage Experiments."

Classification

Higher order taxa:

Bacteria; Proteobacteria; Betaproteobacteria; Hydrogenophilales; Hydrogenophilaceae

Species:

Thiobacillus aquaesulis, T. ferrooxidans, T. denitrificans

Description and Significance

The genus Thiobacillus is also known under the name of Acidithiobacillus. Thiobacillus ferrooxidans are airborne bacteria. This genus is thermophilic, preferring temperatures of 45-50 degrees Celsius. In addition, this is an acidophilic genus, preferring a pH of 1.5 to 2.5. A few species, however, only grow in a neutral pH.

Genome Structure

At present there is not an extensive body of research on the Thiobacillus genome structure.

Cell Structure and Metabolism

A colony of Thiobacillus ferrooxidans. The reddish color is the result of iron production. Jim Horan, "Acid Mine Drainage Experiments.".

Thiobacillus are colorless, rod-shaped, Gram-negative bacteria with polar flagella. They possess an iron oxidase, which allows them to metabolize metal ions such as ferrous iron:

Fe²⁺ + 1/2 O₂ + 2H⁺ --> Fe³⁺ + H₂O

Thiobacillus are strictly aerobic bacteria. All species are respiratory organisms.

Thiobacillus are obligate autotrophic organisms, meaning they require inorganic molecules as an electron donor and inorganic carbon (such as carbon dioxide) as a source. They obtain nutrients by oxidizing iron and sulfur with O2.

Thiobacillus do not form spores; they are Gram-negative Proteobacteria. Their life cycle is typical of bacteria, with reproduction by cell fission.

Ecology

Thiobacillus ferrooxidans is the most common type of bacteria in mine waste piles. This organism is acidophilic (acid loving), and increases the rate of pyrite oxidation in mine tailings piles and coal deposits. It oxidies iron and inorganic sulfur compounds. The oxidation process can be harmful, as it produces sulfuric acid, which is a major pollutant. However, it can also be beneficial in recovering materials such as copper and uranium. It has been suggested that T. ferrooxidans forms a symbiotic relationship with members of the genus Acidiphilium, a bacterial capable of iron reduction. Other species of Thiobacillus grow in water and sediment; there are both freshwater and marine strains.

Some of the reactions undertaken by Thiobacillus. Robertson and Kuenen, "The Genus Thiobacillus."

References

Gardner, Murray N., Shelly M. Deane, and Douglas E. Rawlings. "Isolation of a New Broad-Host-Range IncQ-Like Plasmid, pTC-F14, from the Acidophilic Bacterium Acidithiobacillus caldus and Analysis of the Plasmid Replicon." J Bacteriol. 2001 June; 183(11): 3303–3309.

Levicán, Gloria, Patrice Bruscella, Maritza Guacunano, Carolina Inostroza, Violaine Bonnefoy, David S. Holmes, and Eugenia Jedlicki. "Characterization of the petI and res Operons of Acidithiobacillus ferrooxidans." J Bacteriol. 2002 March; 184(5): 1498–1501.

Peccia, Jordan, Eric A. Marchand, Joann Silverstein, and Mark Hernandez. "Development and Application of Small-Subunit rRNA Probes for Assessment of Selected Thiobacillus Species and Members of the Genus Acidiphilium." Appl Environ Microbiol. 2000 July; 66(7): 3065–3072.

Penner, E., W.J. Eden, and P.E. Grattan-Bellew. "CBD-152. Expansion of Pyritic Shales." Canadian Building Digest. 1 January 1972. Accessed 22 July 2005.

Robertson, Lesley A. and J. Gijs Kuenen. "The Genus Thiobacillus." The Prokaryotes. Release 3.9. Accessed 25 July 2005.

Takai, Masaki, Kazuo Kamimura, and Tsuyoshi Sugio. "A new iron oxidase from a moderately thermophilic iron oxidizing bacterium strain TI-1." Eur. J. Biochem. 268, 1653-1658 (2001).

Wentzel, Erik. "Thiobacillus." Accessed 25 July 2005.