Dehalococcoides

Definition

Dehalococcoides is a genus of anaerobic, gram-negative bacteria that are known for their ability to degrade chlorinated organic compounds, making them an important player in the biogeochemical cycles of these pollutants. These bacteria are found in a variety of environments, including contaminated soils and groundwater, and play a crucial role in the bioremediation of sites impacted by chlorinated solvents and other halogenated compounds.

5 Must Know Facts For Your Next Test

1. Dehalococcoides are obligate anaerobes, meaning they can only grow and thrive in the absence of oxygen.
2. These bacteria are known for their ability to use chlorinated organic compounds as electron acceptors in their anaerobic respiration, a process called reductive dechlorination.
3. Dehalococcoides are capable of completely dechlorinating tetrachloroethene (PCE) and trichloroethene (TCE) to the non-toxic end product, ethene.
4. The presence of Dehalococcoides in contaminated environments is often used as a biomarker for the potential of natural attenuation or engineered bioremediation of chlorinated solvents.
5. Dehalococcoides play a crucial role in the biogeochemical cycling of chlorinated compounds, transforming them into less toxic or non-toxic forms that can be more readily broken down or assimilated into the environment.

Review Questions

• Describe the metabolic capabilities of Dehalococcoides and explain how they contribute to the bioremediation of chlorinated organic compounds.
  • Dehalococcoides are anaerobic bacteria that can use chlorinated organic compounds, such as tetrachloroethene (PCE) and trichloroethene (TCE), as terminal electron acceptors in their anaerobic respiration. This process, known as reductive dechlorination, allows Dehalococcoides to completely transform these persistent pollutants into the non-toxic end product, ethene. The ability of Dehalococcoides to degrade chlorinated solvents makes them a valuable tool in the bioremediation of contaminated sites, as their presence and activity can be used to assess the potential for natural attenuation or guide engineered remediation strategies.
• Explain the role of Dehalococcoides in the biogeochemical cycling of chlorinated compounds and discuss the significance of their presence in the environment.
  • Dehalococcoides play a crucial role in the biogeochemical cycling of chlorinated organic compounds by transforming them into less toxic or non-toxic forms that can be more readily broken down or assimilated into the environment. Through their reductive dechlorination process, Dehalococcoides convert persistent pollutants, such as PCE and TCE, into ethene, which is a much less harmful compound. The presence of Dehalococcoides in contaminated environments is often used as a biomarker to assess the potential for natural attenuation or to guide the implementation of engineered bioremediation strategies, as their activity can effectively remove or transform these hazardous chemicals from the ecosystem.
• Analyze the environmental significance of Dehalococcoides and discuss how their metabolic capabilities and ecological interactions contribute to the overall biogeochemical cycles.
  • Dehalococcoides are of significant environmental importance due to their unique metabolic capabilities and the critical role they play in the biogeochemical cycling of chlorinated organic compounds. As obligate anaerobes, Dehalococcoides are able to use these persistent pollutants as terminal electron acceptors in their anaerobic respiration, transforming them into less toxic or non-toxic end products. This process of reductive dechlorination is essential for the removal and degradation of these hazardous chemicals from contaminated environments, preventing their accumulation and potential harm to ecosystems and human health. Furthermore, the presence of Dehalococcoides serves as a valuable biomarker for assessing the potential for natural attenuation or guiding engineered bioremediation efforts, highlighting their ecological significance in the overall cycling of chlorinated compounds within the environment.

Related terms

Anaerobic Respiration:

A metabolic process in which organisms obtain energy by the oxidation of organic or inorganic compounds, using an electron acceptor other than oxygen, such as nitrate, sulfate, or carbon dioxide.

Bioremediation:

The use of living organisms, typically microbes, to remove or neutralize contaminants from a contaminated site.

Halogenated Compounds: Organic compounds that contain one or more halogen atoms, such as chlorine, bromine, or fluorine, which can be persistent environmental pollutants.