Fulvic and humic acids also involved. B. Redox can be altered by microbial activity. Specific elements that become solubilized include silica, calcium, magnesium, aluminum, cobalt, nickel, lead, potassium, and others. Solubilization is enhanced by organic inputs. Examples of interactions between microorganisms and minerals.
Many minerals exist as sulfides in ores, e.g. copper sulfide, iron sulfide.
Microorganisms can catalyze oxidation of sulfide minerals leading to solubilization of metal ions, e.g. copper, and hence their recovery. Microbial process is economic at low concentrations. This is more important than 2a. Copper metal is recovered. Ferrous iron is then reoxidized to ferric by Thiobacillus ferroxidans in pond, amended with sulfuric acid, and returned to leach pile.