Copper bioreduction and nanoparticle synthesis by an enrichment culture from a former copper mine

Microorganisms can facilitate the reduction of copper (Cu), altering its speciation and mobility in environmental systems and producing Cu-based nanoparticles with useful catalytic properties. However, only a few model organisms have been studied in relation to Cu bioreduction and little work has been carried out on microbes from Cu-contaminated environments. This study aimed to enrich for Cu2+-resistant microbes from a Cu-contaminated soil and explore their potential to reduce Cu2+ and synthesise Cu nanoparticles from solution. We show that an enrichment grown in a Cu-amended medium, dominated by species closely related to Geothrix fermentans, Azospira restricta, and Cellulomonas oligotrophica, can reduce Cu2+ with subsequent precipitation of Cu nanoparticles.