Leptospirillum ferriphilum explained

Leptospirillum ferriphilum is an iron-oxidising bacterium able to exist in environments of high acidity, high iron concentrations, and moderate to moderately high temperatures.[1] It is one of the species responsible for the generation of acid mine drainage[2] and the principal microbe used in industrial biohydrometallurgy processes to extract metals.[3]

Cell Morphology

L. ferriphilum is a gram-negative, spiral-shaped bacterium.[4] L. ferriphilum is an acidophile and a thermotolerant bacteria allowing it to survive in extremely acidic environments and relatively high temperatures.[5] This bacterium is an aerobic organism; it can only survive and grow in an oxygenated environment.[6]

Phylogeny

Leptospirillum ferriphilum is from the domain bacteria, genus Leptosprillium, and species L. ferriphilum.[7] With analysis of the 16S rRNA gene, it was shown the G + C content is 58.5%, which closely resembles group II Leptospirilla; Group II Leptosprilla contains two rrn gene copies.[8]

Metabolic Processes

Leptospirillum ferriphilum is one of the most prevalent iron oxidizers. This bacterium also fixes carbon dioxide through the reductive tricarboxylic acid (TCA) cycle.[9] L. ferriphilum fixes nitrogen through ammonium assimilation, has pH homeostasis mechanisms, has metal resistance systems, and has oxidative stress management systems.[10]

Taxonomy

L. ferriphilum is one of four known species in the Leptospirillum genus. It has been identified as the primary organism active in the generation of acid mine drainage, although the species Acidithiobacillus ferrooxidans was originally described as the dominant biological catalyst for iron oxidation; L. ferriphilum and A. ferrooxidans are typically found in a 2:1 ratio.[1] The high temperature, low pH, and high ferrous iron concentration conditions associated with acidic leaching microenvironments favor L. ferriphilum.

Ecology

L. ferriphilum is a chemolithoautotrophic and obligately anaerobic bacterium that exclusively oxidizes ferrous iron for energy.[11] Certain subtypes are classified as moderately thermophilic. In addition, this species has the ability to fix carbon dioxide, and some strains are capable of fixing nitrogen. Transcriptomics and proteomics show that L. ferriphilum utilizes the tricarboxylic acid cycle to fix carbon dioxide. The microbe is also acidophilic and employs proton pumps within its membranes to maintain its internal pH. Found in highly acidic, metal-rich environments such as the Rio Tinto river in southwest Spain, it contributes to the water's extremely low pH and reddish-orange color.[3] Due to its role in producing acid mine drainage, a major pollutant, it is linked to the acidification and degradation of some riverine and marine environments.

Biomining

L. ferriphilum is central to commercial biomining processes, where the bacteria form biofilms on ore surfaces and catalyze their dissolution via the oxidation of ferrous iron.[12] In bio-oxidation, it is typically used to separate out gold from ores. In bioleaching, it aids the separation of copper from chalcopyrite. Adhesion rates are higher with pyrite than chalcopyrite.[13] Biofilm formation in these oxidation processes is optimal between 30°C to 37°C according to one study[14] and at 41°C in another study. An optimal pH of 1.4 to 1.8 has been correlated with its highest adhesion rate to sulfide metals.

Further reading

External links

Notes and References

  1. Coram . N. J. . Rawlings . D. E. . 2002 . Molecular Relationship between Two Groups of the Genus Leptospirillum and the Finding that Leptospirillum ferriphilum sp. nov. Dominates South African Commercial Biooxidation Tanks That Operate at 40 C . Applied and Environmental Microbiology . 68 . 2 . 838–845 . 10.1128/AEM.68.2.838-845.2002 . 0099-2240 . 126727 . 11823226.
  2. Ojumu . Tunde V. . Petersen . Jochen . 2011 . The kinetics of ferrous ion oxidation by Leptospirillum ferriphilum in continuous culture: The effect of pH . Hydrometallurgy . 106 . 1–2 . 5–11 . 10.1016/j.hydromet.2010.11.007 . 0304-386X.
  3. García-Moyano . Antonio . González-Toril . Elena . Moreno-Paz . Mercedes . Parro . Víctor . Amils . Ricardo . 2008-11-01 . Evaluation of Leptospirillum spp. in the Río Tinto, a model of interest to biohydrometallurgy . Hydrometallurgy . 17th International Biohydrometallurgy Symposium, IBS 2007, Frankfurt a.M., Germany, 2-5 September 2007 . 94 . 1 . 155–161 . 10.1016/j.hydromet.2008.05.046 . 0304-386X.
  4. Issotta, F., Galleguillos, P.A., Moya-Beltrán, A. et al. Draft genome sequence of chloride-tolerant Leptospirillum ferriphilum Sp-Cl from industrial bioleaching operations in northern Chile. Stand in Genomic Sci 11, 19 (2016). https://doi.org/10.1186/s40793-016-0142-1
  5. Cardenas, J. P., Lazcano, M., Ossandon, F. J., Corbett, M., Holmes, D. S., & Watkin, E. (2014). Draft Genome Sequence of the Iron-Oxidizing Acidophile Leptospirillum ferriphilum Type Strain DSM 14647. Genome Announcements, 2(6). https://doi.org/10.1128/genomea.01153-14
  6. Mi, S., Song, J., Lin, J. et al. Complete genome of Leptospirillum ferriphilum ML-04 provides insight into its physiology and environmental adaptation. J Microbiol. 49, 890–901 (2011). https://doi.org/10.1007/s12275-011-1099-9
  7. Coram, N. J., & Rawlings, D. E. (2002). Molecular Relationship between Two Groups of the Genus Leptospirillum and the Finding that Leptospirillum ferriphilum sp. nov. Dominates South African Commercial Biooxidation Tanks That Operate at 40°C. Applied and Environmental Microbiology, 68(2), 838–845. https://doi.org/10.1128/aem.68.2.838-845.2002
  8. Vardanyan, A., Khachatryan, A., Castro, L., Willscher, S., Gaydardzhiev, S., Zhang, R., & Vardanyan, N. (2023). Bioleaching of Sulfide Minerals by Leptospirillum ferriphilum CC from Polymetallic Mine (Armenia). Minerals, 13(2), 243. MDPI AG.http://dx.doi.org/10.3390/min13020243
  9. Christel, S., Herold, M., Sören Bellenberg, Mohamed El Hajjami, Buetti-Dinh, A., Pivkin, I. V., Sand, W., Wilmes, P., Poetsch, A., & Dopson, M. (2017). Multi-omics Reveals the Lifestyle of the Acidophilic, Mineral-Oxidizing Model Species Leptospirillum ferriphilum T. Applied and Environmental Microbiology, 84(3). https://doi.org/10.1128/aem.02091-17
  10. Mi, S., Song, J., Lin, J. et al. Complete genome of Leptospirillum ferriphilum ML-04 provides insight into its physiology and environmental adaptation. J Microbiol. 49, 890–901 (2011). https://doi.org/10.1007/s12275-011-1099-9
  11. name=":1"/>Christel . Stephan . Herold . Malte . Bellenberg . Sören . El Hajjami . Mohamed . Buetti-Dinh . Antoine . Pivkin . Igor V. . Sand . Wolfgang . Wilmes . Paul . Poetsch . Ansgar . Dopson . Mark . 2018-01-17 . Multi-omics Reveals the Lifestyle of the Acidophilic, Mineral-Oxidizing Model Species Leptospirillum ferriphilumT . Applied and Environmental Microbiology . 84 . 3 . e02091–17 . 10.1128/AEM.02091-17 . 5772234 . 29150517.
  12. name=":1"/>Christel . Stephan . Herold . Malte . Bellenberg . Sören . El Hajjami . Mohamed . Buetti-Dinh . Antoine . Pivkin . Igor V. . Sand . Wolfgang . Wilmes . Paul . Poetsch . Ansgar . Dopson . Mark . 2018-01-17 . Multi-omics Reveals the Lifestyle of the Acidophilic, Mineral-Oxidizing Model Species Leptospirillum ferriphilumT . Applied and Environmental Microbiology . 84 . 3 . e02091–17 . 10.1128/AEM.02091-17 . 5772234 . 29150517.
  13. Africa . Cindy-Jade . van Hille . Robert P. . Harrison . Susan T. L. . 2013-02-01 . Attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum cultured under varying conditions to pyrite, chalcopyrite, low-grade ore and quartz in a packed column reactor . Applied Microbiology and Biotechnology . en . 97 . 3 . 1317–1324 . 10.1007/s00253-012-3939-x . 1432-0614.
  14. Liu . Jie . Wu . Weijin . Zhang . Xu . Zhu . Minglong . Tan . Wensong . 2017-03-10 . Adhesion properties of and factors influencing Leptospirillum ferriphilum in the biooxidation of refractory gold-bearing pyrite . International Journal of Mineral Processing . 160 . 39–46 . 10.1016/j.minpro.2017.01.001 . 0301-7516.

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