Details for Ferroglobus placidus

Ferroglobus is related to Archaeoglobus but is not a sulfate-reducing bacterium. Instead, Ferroglobus is an iron-oxidizing chemolithotrophic autotroph, conserving energy from the oxidation of Fe²⁺ to Fe³⁺ coupled to the reduction of NO₃^- to NO₂^- plus NO. Ferroglobus can also use H₂ or H₂S as electron donors in its energy metabolism. Ferroglobus was isolated from a shallow marine hydrothermal vent and grows optimally 85°C. Ferroglobus is interesting for several reasons, but especially so because of its ability to produce Fe³⁺ from Fe²⁺ under anoxic conditions. The mechanism for the formation of Fe³⁺ in ancient rocks, previously assumed to have been from the oxidation of Fe²⁺ by O₂ produced by cyanobacteria, is now being questioned with the discovery that anoxic routes to the production of Fe³⁺ exist from the activiteis of organisms like Ferroglobus and certain anoxygenic phototrphic bacteria.