Enhancement Mechanism of Stibnite Dissolution Mediated by under Extremely Acidic Condition.

Oxidative dissolution of stibnite (SbS), one of the most prevalent geochemical processes for antimony (Sb) release, can be promoted by Sb-oxidizing microbes, which were studied under alkaline and neutral conditions but rarely under acidic conditions. This work is dedicated to unraveling the enhancement mechanism of stibnite dissolution by typical acidophile under extremely acidic conditions. The results of solution behavior showed that the dissolution of SbS was significantly enhanced by , with lower pH and higher redox potential values and higher [Sb(III)] and [Sb(V)] than the sterile control. The surface morphology results showed that the cells adsorbed onto the mineral surface and formed biofilms. Much more filamentous secondary minerals were formed for the case with . Further mineral phase compositions and Sb/S speciation transformation analyses showed that more secondary products SbO/SbO, SbO/SbO, SO, as well as intermediates, such as S, SO were formed for the biotic case, indicating that the dissolution of SbS and the Sb/S speciation transformation was promoted by . These results were further clarified by the comparative transcriptome analysis. This work demonstrated that through the interaction with SbS, promotes S/Sb oxidation, so as to enhance S/Sb transformation and thus the dissolution of SbS.