Characteristics of phosphate solubilization by an isolate of a tropical Penicillium rugulosumand two UV‐induced mutants

After screening several fungal isolates obtained from Venezuelan soils, the isolate IR‐94MF1 of Penicillium rugulosumwas selected for its high mineral phosphate solubilizing activity (Mps+) with hydroxyapatite. Mutants with altered (Mps−) or amplified activity (Mps++) were obtained by UV irradiation of conidia. When glucose was used as the sole C source by the fungus, gluconic acid was associated with the hydroxyapatite activity. In solid media, in comparison to glucose and maltose, sucrose appeared to be the best C source for the solubilization of hydroxy‐apatite and FePO4.