Bioleaching of metals from wastes and low-grade sources by HCN-forming microorganisms

Microbial leaching via biocyanidation process enables efficient extraction of precious metals from low-grade ores and increases attention in mineral industries for applying green and environmentally friendly leaching methods. Microbial cyanidation can be applied in cyanidation process mobilizing precious metals from ores and scraps. Biological solubilization processes also recover metals from secondary raw materials such as e-wastes, car catalysts, coins, etc. In comparison with conventional technologies, biomobilization is associated with advantages including simple operation, reduced cost, and less environmental risks. This review was performed to describe a perspective on metal biocyanidation by applying cyanogenic microorganisms. Factors influencing yield of biocyanidation and electrochemical approaches of metal recovery were discussed. This study also addresses future advances of industrial applications of microbial mobilization of some metals as soluble cyanide complex from secondary resources.