Bioleaching is a process within environmental biotechnology that involves the extraction of metals from their ores through the use of living microorganisms. This method offers an eco-friendly and cost-effective alternative to traditional metallurgical techniques such as smelting and chemical leaching, which often involve high energy consumption and the release of toxic by-products. In bioleaching, certain microorganisms, primarily bacteria and fungi, are employed to solubilize metals from ores, enabling their recovery from low-grade mineral resources that would otherwise be economically unfeasible to exploit. The process has been widely applied for the recovery of metals such as copper, gold, nickel, uranium, and zinc. The bioleaching process can occur through two primary mechanisms: direct and indirect bioleaching. In direct bioleaching, microorganisms attach themselves to the surface of the mineral ore and directly oxidize the metal compounds. For instance, in the bioleaching of sulfide ores, bacteria such as *Acidithiobacillus ferrooxidans* and *Leptospirillum ferrooxidans* oxidize ferrous ions (Fe²⁺) to ferric ions (Fe³⁺), which then react with the sulfide minerals to release soluble metal ions. Direct contact between the bacteria and mineral surface enhances the efficiency of metal solubilization. On the other hand, indirect bioleaching does not require direct contact between the microorganism and the ore. Instead, the microorganisms oxidize an intermediate compound, such as iron or sulfur, to generate an oxidizing agent that chemically interacts with the mineral to release the metal. For example, in copper bioleaching, the bacteria oxidize ferrous ions to ferric ions, which subsequently react with copper sulfide ores to form soluble copper sulfate. A classic example of bioleaching is the recovery of copper from low-grade chalcopyrite (*CuFeS₂*). In this process, *Acidithiobacillus ferrooxidans* and *Leptospirillum* species oxidize ferrous iron and sulfur compounds present in the ore. The overall chemical reaction involves the oxidation of sulfide minerals to sulfate, releasing copper ions into solution. Another example is the bioleaching of gold, which often occurs in ores containing arsenopyrite (*FeAsS*) or other sulfide minerals. Here, microorganisms oxidize the sulfide matrix, freeing encapsulated gold particles that can be recovered using conventional methods such as cyanidation. Uranium bioleaching is another significant application, where *Thiobacillus* species facilitate the solubilization of uranium from low-grade ores by oxidizing uranium compounds in acidic conditions.