AUTHOR=Christel Stephan , Herold Malte , Bellenberg Sören , Buetti-Dinh Antoine , El Hajjami Mohamed , Pivkin Igor V. , Sand Wolfgang , Wilmes Paul , Poetsch Ansgar , Vera Mario , Dopson Mark TITLE=Weak Iron Oxidation by Sulfobacillus thermosulfidooxidans Maintains a Favorable Redox Potential for Chalcopyrite Bioleaching JOURNAL=Frontiers in Microbiology VOLUME=9 YEAR=2018 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.03059 DOI=10.3389/fmicb.2018.03059 ISSN=1664-302X ABSTRACT=
Bioleaching is an emerging technology, describing the microbially assisted dissolution of sulfidic ores that provides a more environmentally friendly alternative to many traditional metal extraction methods, such as roasting or smelting. Industrial interest is steadily increasing and today, circa 15–20% of the world’s copper production can be traced back to this method. However, bioleaching of the world’s most abundant copper mineral chalcopyrite suffers from low dissolution rates, often attributed to passivating layers, which need to be overcome to use this technology to its full potential. To prevent these passivating layers from forming, leaching needs to occur at a low oxidation/reduction potential (ORP), but chemical redox control in bioleaching heaps is difficult and costly. As an alternative, selected weak iron-oxidizers could be employed that are incapable of scavenging exceedingly low concentrations of iron and therefore, raise the ORP just above the onset of bioleaching, but not high enough to allow for the occurrence of passivation. In this study, we report that microbial iron oxidation by