Insights into the defensive mechanism of bioleaching microorganisms under extreme environmental copper stress

Abstract

As the demand for metal resources increases and the quality and availability of rich ore resources decline, the focus is shifting to low-cost, eco-friendly bioleaching technologies that can effectively utilize low-grade minerals. The stress on bioleaching microorganisms due to high concentrations of metal ions in the bioleaching system is one of the most important factors limiting the effectiveness of bioleaching. Using the common copper-bearing ore bioleaching process as an example, the copper ion concentration reached 6 g/L. An in-depth examination of the copper defensive mechanism of bioleaching microorganisms will help elucidate the physiological mechanism of such extremophiles and pave the way for future genetically engineered highly efficient strains. We elaborate on the copper tolerance mechanism of extremophiles through the lens of biofilms, cell membranes, metal transport mechanisms, intracellular buffer mechanisms, and energy metabolism.