Reduction of Inorganic Compounds by Soil Microorganisms

Isolates of Pichia guillermondii and Micrococcus sp. obtained from soil converted selenate, selenite, tellurate, and tellurite to the elemental forms, vanadate to a vanadyl compound, molybdate and molybdenum trioxide to a molybdenum blue compound, arsenate to arsenite, MnO 2 to the manganous ion, nitrate to nitrite, and chlorate to a less oxidized form. Resting cell suspensions and cell‐free extracts of the two organisms also effected the reduction of most of the inorganic compounds and anions. The capacity to reduce selenate, selenite, tellurate, tellurite, vanadate, molybdate, molybdenum trioxide, arsenate, chlorate, and MnO 2 was found to be common to soil microrganisms. It is suggested that these microbial reactions may be important in changing the solubility, availability, or toxicity of certain elements in soil.