Assessing the Parameters for Optimum Biotransformation of Carbonaceous Matter by Phanerochaete chrysosporium

Refractory carbonaceous gold ores pose challenges during cyanidation of gold due to the presence of carbonaceous matter (CM) which preg-robs dissolved gold, and this results in a decreased recovery. In an on-going study, the fungus, Phanerochaete chrysosporium has been used to deactivate CM and decrease its ability to preg-rob aurocyanide. P. chrysosporium has been reported to biotransform CM by surface oxidation, which leads to disruption of the continuous graphitic structure necessary for adsorption, and alteration of the pores suitable for aurocyanide adsorption. The present study focused on using anthracite coal as surrogate for CM, and establishing fungal-treatment parameters that bring about maximum decrease in preg-robbing by the anthracite-grade CM. The results indicate that P. chrysosporium can survive in several growth media, and possesses the ability to deactivate anthracite in a wide range of time, pulp density, temperature, pH, and level of agitation. A processing time of 5-7 days at pH 4 and 37°C gave the best conditions. The best pulp densities for stationary and shake culturing respectively were 60% and 25%.