Realgar (As4S4) bioprecipitation in microcosm fed by a natural groundwater and organic matter

The Microbiology of Metal Mine Waste: Bioremediation Applications and Implications for Planetary Health

“…In this study, abundant orpiment precipitates were formed extracellularly, as well as some intracellular nanoparticles observed near the cytoplasmic membrane. These processes are environmentally relevant: microbial formation of As sulfide minerals such as realgar has been shown to occur under strictly anaerobic conditions in wetland soils (Drahota et al, 2017;Falteisek et al, 2019) and As sulfide minerals found in salt flats were confirmed to have a microbial origin (Demergasso et al, 2007). A sulfate-reducing consortium supplied with glycerol was able to completely remove As from acid mine drainage at pH 4 by precipitation as orpiment and realgar (Le Pape et al, 2017).…”