Recovery of gold from thiourea solutions using microorganisms.
The recovery of gold from gold-thiourea solutions using various types of waste biomass was investigated. All organisms tested, namely, Saccharomyces cerevisiae, Spirulina platensis and Streptomyces erythraeus removed gold rapidly from gold-thiourea solutions. The process of gold accumulation was pH-dependent for Saccharomyces ceresvisiae and Streptomyces erythraeus and independent of pH in the case of Spirulina platensis. Of all strains of microorganisms examined, Spirulina platensis had the highest affinity and capacity for gold even at low pH values. Thus, all three microorganisms tested for their ability to recover gold from gold-thiourea solutions can therefore be used in biotechnological applications, especially Spirulina platensis which has the highest binding capacity for gold at low pH values.