sulphatereducing

Sulphatereducing refers to a group of microorganisms, primarily bacteria and archaea, that utilize sulfate as a terminal electron acceptor during anaerobic respiration. These organisms, often called sulfate-reducing organisms (SROs), play a significant role in the global sulfur cycle. Instead of using oxygen for respiration, which is common for many other microbes, SROs extract oxygen atoms from sulfate ions, a process that results in the production of hydrogen sulfide (H2S). This process is crucial for the decomposition of organic matter in environments lacking oxygen.

Sulfate-reducing bacteria are found in a wide variety of anaerobic environments, including marine sediments, freshwater sediments, soils, groundwater, and even in the digestive tracts of animals. They are often associated with environments rich in organic matter and sulfate. The activity of these microbes can have both beneficial and detrimental effects. In natural environments, they contribute to nutrient cycling and the removal of organic pollutants. However, in industrial settings, their metabolic by-product, hydrogen sulfide, can be highly corrosive, leading to pipeline damage and the souring of oil and gas reservoirs. Furthermore, hydrogen sulfide is toxic and has a characteristic rotten egg smell.

The biochemical process involves the reduction of sulfate (SO4^2-) through a series of enzymatic steps to sulfide (S^2-). Different species of sulfate-reducing organisms have varying electron donors they can utilize, commonly including organic compounds like acetate and lactate, or inorganic compounds like hydrogen. The diversity of sulfate-reducing bacteria is extensive, with genera such as Desulfovibrio, Desulfobacter, and Desulfotomaculum representing common examples. Their metabolic activity is a key component of anaerobic biogeochemical cycles.