text: Many sulfate reducers are organotrophic, using carbon compounds such as lactate and pyruvate (among many others) as electron donors, while others are lithotrophic, using hydrogen gas () as an electron donor.  Some unusual autotrophic sulfate-reducing bacteria (e.g. Desulfotignum phosphitoxidans) can use phosphite () as an electron donor whereas others (e.g. Desulfovibrio sulfodismutans, Desulfocapsa thiozymogenes, Desulfocapsa sulfoexigens) are capable of sulfur disproportionation (splitting one compound into two different compounds, in this case an electron donor and an electron acceptor) using elemental sulfur (S), sulfite (), and thiosulfate () to produce both hydrogen sulfide () and sulfate ().