Potential of extremophilic and native microbial consortia in the bioleaching of heavy metals on mining process

Mining is a significant economic activity in many countries, resulting in the release of wastewater with high concentrations of heavy metals and other harmful compounds. Leaching is a treatment technique for these effluents, allowing the recovery of precious metals through solubilization, but it generates large amounts of tailings and waste effluents. Microbial leaching (bioleaching) is a biological strategy where microbes are used to solubilize precious metals in insoluble substrates through microbial metabolism or metabolic products. Extremophilic microorganisms, particularly those formed by indigenous consortia (bacteria and fungi), have versatile metabolic traits that are highly valued. Some heterotrophic bacteria adapt to acid environments and high concentrations of heavy metals as a defense mechanism against heavy metals. The pH is a fundamental parameter of bioleaching, and for efficient bioleaching, microbial consortia composed of mixed cultures, mainly extremophilic microbes, are proposed due to their poly-resistance to a reduced pH, likely to favor the recovery of metal. This chapter addresses the main characteristics of extremophilic microorganisms forming native microbial consortia and their biotechnological potential in the bioleaching of heavy metal-rich mining effluents. The aim is to highlight advanced strategies or methods for studying this group of microorganisms, considering their enormous potential as a priceless source of compounds of interest for various fields such as medicine, agriculture, and mining.