Geochemical and microbial characterization of antimony metabolism by microbial consortium obtained from stibnite mine tailing soil

Abstract

Stibnite was widely used for mineral specimens and alloys. Its main component, antimony (Sb), is a highly toxic element. Although the concentrations of Sb in soils are generally low, elevated levels of Sb have been released via mining and other anthropogenic activities. Microorganisms are likely to play important roles in Sb redox transformations in the environment. In this study, we characterized Sb(V)-reducing anaerobic consortium by using physiological, geochemical, and genomic approaches. An anaerobic consortium was enriched from stibnite mine tailing soil by its ability to reduce Sb(V) In addition to Sb(V), other electron acceptors such as As(V), Fe(III) citrate, and anthraquinone-2,6-disulfonate (AQDS) were reduced in the presence of lactate. Draft genome sequence of this consortium was determined and majority of the sequences (>90%) were assigned to Firmicutes with 79% of sequences belonged to the genus Desulfitobacterium. Functional genes associated with arsenic resistance, nitrate reduction, nitrogen fixation, polysulfide reductase, and putative reductive dehalogenase were found in the genome, indicating metabolic versatility of this consortium.