Reductive Dissolution of Iron Oxides and Manganese Bioleaching by <i>Acidiphilium cryptum</i> JF-5

Abstract

In the development of new processes to use the potential of iron reducing bacteria,Acidiphilium cryptum, the main bacteria involved in the reduction of Fe (III) compounds in acidic environments, could play an important biohydrometallurgical role. Thus, the bioleaching of hematite, goethite and a low-grade manganese ore was assayed, in vials and columns, using three different media; two of which included a ligand, oxalate, or a redox mediator, thionine.Although the presence ofA. cryptumwas essential for promoting the dissolution of both iron oxides and the bioleaching of manganese ore, the addition of oxalate to the media tripled and quadrupled the microbial dissolution of hematite and goethite, respectively. Oxalate also had a positive effect in assays performed in columns, however, the addition of thionine to the medium allowed to reach significant hematite dissolution.