Abstract
The ability of three species of Penicillium, isolated from soil, and Fusarium solani to solubilize insoluble fluorides was studied. All three Penicillium species and F. solani were capable of solubilizing calcium fluoride and fluorite. A single species of Penicillium and F. solani also solubilized a range of insoluble fluoride compounds. The ability of F. solani to solubilize calcium fluoride varied with the type of carbon source used and increased with an increasing amount of added fluoride up to 2% (w/v). No growth occurred above this amount. The addition of 1.5% (w/v) calcium fluoride also inhibited the formation of the black spores that are typically produced by Aspergillus niger, although sporulation returned when the fungus was transferred to medium lacking calcium fluoride.