Abstract
Ammonium and nitrite that are substrates for anammox bacteria are present at low concentrations in marine sediments. It is hypothesized that marine anammox bacteria survive by obtaining energy from not only ammonium and nitrite but also other substrates such as heavy metals. In the present study, the possibility of metabolic pathways of marine anammox bacteria regarding to heavy metals (manganese and iron), sulfate, and formate were investigated using batch experiments. The manganese reduction rate, manganese oxidation rate, iron reduction rate, and sulfate reduction rate of “Candidatus Scalindua sp.” were 0.16, 0.005, 0.01, 2.05 nmol mg-protein-1min-1, respectively, which indicated that marine anammox might utilize these compounds as electron donor or acceptor. The fraction of sulfite production was approximately 60% of the sulfate reduction, which indicated the production of hydrogen sulfide and iron sulfide.
