Search results
Results from the WOW.Com Content Network
Aerobic sulfide-oxidizing bacteria usually oxidize sulfide to sulfate and are obligate or facultative chemolithoautotrophs. The latter can grow as heterotrophs , obtaining carbon from organic sources, or as autotrophs, using sulfide as the electron donor (energy source) for CO 2 fixation. [ 3 ]
The Sox pathway is a multi enzyme pathway capable of oxidizing sulfide, sulfite, elemental sulfur, and thiosulfate to sulfate. [10] Dissimilatory oxidation converts sulfite to elemental sulfur. [9] Sulfur oxidizing species include and the genera of Thiomicrospira, Halothiobacillus, Beggiatoa, Persephonella, and Sulfurimonas.
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]
Beggiatoa group is mainly composed by chemolithotrophic, sulfide-oxidizing bacteria. However, the range of possible metabolic pathways is very diversified, varying from the heterotrophy to the chemolithoautotrophy. Because of this huge variability the diverse bacteria of this genus can differ greatly from each other. [15]
Most species oxidize sulfur compounds for energy metabolism. They often use nitrate as an electron acceptor, which contributes to the detoxification of sulfide-rich environments. These bacteria thrive when there is a gradient between oxygenated and anoxic zones, that can occur around hydrothermal vents.
The majority of bacteria present in these reservoirs are uncultured bacteria, which have not been studied deeply. [31] [32] Bacteria of the aforementioned genera derive their energy from the oxidation of reduced sulfur compounds (i.e. sulfide and thiosulfate), which suggests direct competition among them for sulfur-containing compounds [3] [4] [6]
T. namibiensis is more prevalent in areas with free gas, suggesting that the presence of suspended sulfide is beneficial to the bacteria. T. namibiensis will oxidize the hydrogen sulfide (H2S) from the sediment into sulfur and sulfide, thus allowing less sulfide into the water column and detoxifying the water.