M. Gorji, M.R. Hosseini, A. Ahmadi, Comparison and optimization of the biocyanidation potentials of B. megaterium and P. aeruginosa for extracting gold from an oxidized copper-gold ore in the presence of residual glycine, Hydrometallurgy (2020) 191: 105

Considering the environmental issues of cyanide ion, cyanogenic bacteria which are capable of cyanide genesis may be regarded as a potential alternative to conventional cyanidation. The capacities of two cyanogenic bacterial strains namely Pseudomonas aeruginosa and Bacillus megaterium for the cyanide production and gold bioleaching from the pure gold particles and an oxidized gold-bearing ore (6.2 g/ton) were compared. Also, in order to maximize the cyanide bio-production and subsequently the gold recovery, the influences of the initial pH, glycine, FeSO_4, NaH₂PO₄, and MgSO₄ concentrations in the growth media were studied and optimized. In the optimal culture condition, P. aeruginosa and B. megaterium produced 66.35 and 67.05 mg/l cyanide, respectively, and 2.5 g/l glycine remained unconsumed. Therefore, bioleaching experiments were performed under the synergistic effect of the cyanide …