Feasting on Minerals

Abstract

Far up in the Chilean Andes, in remote arid regions seemingly inhospitable to life, intrepid microorganisms thrive on a diet of rocks and air. Unfazed by long periods of desiccation or high ultraviolet energy flux, they grow in baths of sulfuric acid replete with toxic metals. The microbes fix carbon dioxide into biomass by exploiting the energy to be gained by "eating" (oxidizing) minerals that contain reduced forms of iron and sulfur, such as chalcopyrite (CuFeS_2). Through their metabolism, these microbes mobilize precious metals from ore deposits into solution, making them powerful catalysts for biomining (see the first figure) (1). Recent research has begun to elucidate how they achieve this remarkable feat.