An integrated biotechnological approach to gold processing-an Indian experience

Abstract

The role of biotechnology in different facets of gold extraction metallurgy is illustrated with respect to biogenesis of gold ore deposits, biobenefication, bioliberation and bioenvironmental control. The use and commerical potential of this technology are discussed with reference to the mining and processing of Hutti gold ores. A microbial survey of the Hutti gold mines revealed the ubiquitous presence of various autotrophic and heterotrophic bacteria, fungi and yeast of relevance in gold processing. The possible roles played by different indigenous microorganisms in the formation, conversion and transport of gold along with various associated minerals have been brought out. Similarly, the role of Thiobacillus ferrooxidans in the flotation beneficiation of gold-bearing sulphides and in enhancing gold recovery from refractory sulphide ores and concentrates has been demonstrated. Direct gold solubilization could be achieved by Bacillus spp. Various fungi and yeast were found to be useful in the biosorption of gold and other base metals from cyanide effluents. It could thus show that biotechnology could be beneficially utilized in different stages of precious metal processing spanning from mining to waste disposal.