Novel insights into microbial strategies for antimony (Sb) transformation coupled with carbon utilization in...

Microbial-mediated antimony (Sb) metabolism and its coupling with bio-essential elements cycles are not only crucial to the biogeochemistry of Sb-contaminated groundwater but also have potential implications for human health. However, the ways in which Sb contamination affects microbial carbon, nitrogen, and sulfur metabolism, particularly carbon-utilization strategies, remain poorly understood and lack direct experimental confirmation. Herein, well and spring water samples were collected from the Xikuangshan (XKS) mine to investigate microbial responses and functional adaptations. The results showed that microbial communities in well and spring became similar during the wet season, with total Sb identified as a major shaping force in this complex environment. Communities in low-Sb samples harbored a higher potential functional diversity, whereas those in high-Sb samples exhibited convergent metabolic potential, with enrichment in genes for pyruvate metabolism. Metagenome-assembled genomes (MAGs) in low-Sb samples harbored more pathways for inorganic carbon utilization, including cynT, pycA, PRK, rbcL, and rbcS genes, primarily derived from the phyla Bdellovibrionota and Eremiobacterota. Microcosm cultivation confirmed a preference for inorganic carbon (NaHCO₃) in low-Sb samples and organic carbon sources (pyruvate) in high-Sb samples. These findings provide new genomic insights and experimental evidence for the coupling between Sb transformation and carbon utilization in contaminated aquifers.