Search results
Results From The WOW.Com Content Network
The oxidation of reduced sulfur compounds is performed exclusively by Bacteria and Archaea.All the Archaea involved in this process are aerobic and belong to the Order Sulfolobales, [19] [20] characterized by acidophiles (extremophiles that require low pHs to grow) and thermophiles (extremophiles that require high temperatures to grow).
Sulfide Oxidation. Under aerobic conditions, sulfide is oxidized to sulfur and then sulfate by sulfur oxidizing bacteria, such as Thiobacillus, Beggiatoa and many others. Under anaerobic conditions, sulfide can be oxidized to sulfur and then sulfate by Purple and Green sulfur bacteria. H 2 S → S 0 → SO 2− 4. Sulfur Oxidation
Some bacteria use light energy to couple sulfur oxidation to carbon dioxide (CO 2) fixation for growth. These fall into two general groups: green sulfur bacteria (GSB) and purple sulfur bacteria (PSB). [6] However, some Cyanobacteria are also able to use hydrogen sulfide as an electron donor during anoxygenic photosynthesis. [7]
These bacteria thrive when there is a gradient between oxygenated and anoxic zones, that can occur around hydrothermal vents. This is where Thiotrichales usually form microbial mats and biofilms is sulfur is abundant. This species of microbe can also be present in cold seep ecosystems where methane and sulfide seep through the seafloor.
In autotrophic Beggiatoa, sulfide is a source of energy and electrons for carbon fixation and growth. The oxidation of sulfide can be aerobic or anaerobic, in fact it can be coupled with the reduction of oxygen or with the reduction of nitrate.
The energy obtained from inorganic oxidation varies depending on the substrate and the reaction. For example, the oxidation of hydrogen sulfide to elemental sulfur by ½O 2 produces far less energy (50 kcal/mol or 210 kJ/mol) than the oxidation of elemental sulfur to sulfate (150 kcal/mol or 627 kJ/mol) by 3/2 O 2,. [10]
Acidithiobacillus is a genus of the Acidithiobacillia in the phylum "Pseudomonadota".This genus includes ten species of acidophilic microorganisms capable of sulfur and/or iron oxidation: Acidithiobacillus albertensis, Acidithiobacillus caldus, Acidithiobacillus cuprithermicus, Acidithiobacillus ferrianus, Acidithiobacillus ferridurans, Acidithiobacillus ferriphilus, Acidithiobacillus ...
Sulfur oxidation involves the oxidation of reduced sulfur compounds (such as sulfide H 2 S), inorganic sulfur (S), and thiosulfate (S 2 O 2− 3) to form sulfuric acid (H 2 SO 4). A classic example of a sulfur-oxidizing bacterium is Beggiatoa, a microbe originally described by Sergei Winogradsky, one of the founders of environmental microbiology.