ABSTRACT
This chapter discusses the microbes-to-metal interactions and all the aspects of microbial activities. Harmful environmental footprints due to a large amount of cyanide used in gold leaching from ores have created the need to search for an alternative without compromising recovery efficiency. Cyanide has a proven record of higher leaching rate and recovery efficiency with a low-cost carbon adsorption technique and has yet to be replaced by another reagent on a large, commercial scale. Therefore, bio-cyanidation is gaining much attention in recent times by the use of a variety of cyanogenic microorganisms. The microbial activity in gold metallurgy is an environmentally friendly operation. The bio-oxidation performed with microbes eliminates or lowers the uses of hazardous chemicals and rejects the use of energy intensive roasting/pressure oxidation process. In leaching of gold by the means of bio-cyanidation, regulation of cyanide concentration as low as 1 mM is significantly less when compared to the amount of cyanide in chemical cyanidation.
