Prospects of bioleaching of coppernickel ores by acidophilic chemolithotrophic microorganisms from thermal springs of Kamchatka

Higher temperatures can yield better metal extraction results in bacterial-chemical processing of sulfide ores or concentrates. Thermophilic archaea or moderately thermophilic bacteria participate in the oxidation of sulfide minerals at temperatures above 60 °C. Bioleaching with thermophiles can be conducted at higher temperatures, as these organisms can withstand the heat generated during the exothermic biooxidation of copper ores. These microorganisms naturally inhabit metal-rich and sulfur-rich hot springs and solfataras. The Kamchatka Peninsula and the Kuril Islands are regions of active volcanic activity and hydrothermal manifestations, with thermal outlet temperatures ranging between 15 and 96 °C and pH levels of 3.45–4.62. Hydrothermal spring waters contain carbon dioxide, hydrogen sulfide, and other reduced sulfur compounds, as well as silicon, ammonia, phosphorus, iron, manganese, zinc, and other elements. These regions could represent prospective habitats for isolating thermophilic chemolithotrophic microorganisms. Current scientific research in the hydrothermal regions of Kamchatka and the Kuril Islands focuses primarily on diatom algae and saprophytes. However, exploring iron-oxidizing and sulfur-oxidizing acidophiles from these acidic hydrothermal sources offers an opportunity to discover valuable microorganisms for the bioleaching of copper-nickel ores. This review provides general information about the thermophilic chemolithotrophic bacteria and archaea isolated from geothermal springs on the Kamchatka Peninsula and the Kuril Islands. The article describes the role of thermoacidophilic microorganisms in bioleaching.