16S rRNA sequencing of microbial communities mediating photoelectron-assisted antimonate reduction in mining-impacted sediments

Antimony (Sb) contamination from mining activities poses significant ecological and human health risks. In anoxic river sediments, microbial Sb(V) reduction represents a critical natural attenuation pathway, yet the underlying mechanisms remain poorly understood. This project investigates a novel process-photoelectron-assisted Sb(V) reduction (PESbR)-where indigenous sediment microorganisms utilize photoelectrons generated from dissolved organic matter (DOM) under illumination. We employed 16S rRNA gene sequencing to profile microbial community composition and dynamics under PESbR conditions, revealing the enrichment of non-phototrophic taxa such as Sphingomonas, Achromobacter, Cupriavidus, and Bosea. These microorganisms demonstrated the capacity to couple DOM-derived photoelectrons to Sb(V) reduction, suggesting a previously unrecognized microbial photoelectrophy mechanism. The generated 16S rRNA dataset provides insights into the diversity, ecological niches, and functional potential of microbial assemblages mediating Sb redox cycling in mining-impacted sediments, with implications for bioremediation strategies in Sb-polluted aquatic ecosystems.