Sulfátredukció

Sulfátredukció, also known as sulfate reduction, is a biogeochemical process by which sulfate ions (SO4^2-) are reduced to sulfide ions (S^2-). This process is primarily carried out by a group of anaerobic microorganisms known as sulfate-reducing bacteria (SRBs). SRBs utilize sulfate as an electron acceptor in their metabolic respiration, often in environments where oxygen is scarce, such as sediments, marshlands, and deep subsurface geological formations.

The overall reaction for microbial sulfate reduction can be simplified as: SO4^2- + 8e- + 8H+ -> HS- + 2H2O. The hydrogen sulfide (H2S) produced can then dissociate into HS- and S^2- depending on the pH of the environment. This process plays a significant role in the global sulfur cycle, contributing to the recycling of sulfur.

Sulfate reduction is important in various natural and anthropogenic contexts. In marine environments, it is a major pathway for sulfur cycling. In industrial settings, SRBs can cause significant problems, including microbiologically influenced corrosion (MIC) of metal structures due to the production of corrosive hydrogen sulfide. Conversely, sulfate reduction can also be harnessed for beneficial applications, such as bioremediation of heavy metals and the production of biofuels. The activity of SRBs can be influenced by factors such as the availability of electron donors (e.g., organic matter, hydrogen) and sulfate, as well as temperature and pH.