Bioleaching is a biological process that involves the extraction of metals from their ores using microorganisms, offering an environmentally friendly and economically viable alternative to traditional pyrometallurgical and hydrometallurgical techniques. This process uses naturally occurring or genetically engineered microbes to catalyze the solubilization of metals, making them recoverable from low-grade ores that would otherwise be considered uneconomical. Bioleaching has gained increasing attention in environmental biotechnology due to its low energy requirements, reduced air pollution, and ability to treat ores that are too poor in metal content for conventional processing. The fundamental principle of bioleaching relies on the ability of certain microorganisms, particularly bacteria such as Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferrooxidans, to oxidize metal sulfides and generate sulfuric acid and ferric ions, which help dissolve the metal from the ore matrix. There are several bioleaching processes depending on the type of metal and the microbial mechanism involved. The most widely applied bioleaching process is the direct or indirect leaching of sulfide ores. In direct bioleaching, microorganisms oxidize the sulfide minerals enzymatically, leading to the solubilization of metals. For example, in the bioleaching of copper from chalcopyrite (CuFeS₂), bacteria oxidize sulfide to sulfate while simultaneously releasing copper ions into solution. Indirect bioleaching, also known as non-contact leaching, involves bacteria oxidizing ferrous iron (Fe²⁺) to ferric iron (Fe³⁺), which then acts as a chemical oxidant on the metal sulfides. This cyclic regeneration of ferric iron makes the process continuous. An example is the bioleaching of