Biosorption of uranium and heavy metals using some local fungi isolated from phosphatic fertilizers

Abstract

A number of 26 fungal cultures were isolated from different phosphatic sources, including phosphate fertilizers and rock phosphate. The highest number and percentage of isolates were obtained from tri-phosphate fertilizer and rock phosphate samples (9 isolates with 34.6% for each sample) and then 8 isolates with 30.8% from monophosphate fertilizer. These isolates were tested for heavy metals biosorption on solid medium supplemented with different metal ions at concentration of 50 ppm. Eighteen out of 26 isolates were able to grow on solid medium containing heavy metals. The selected isolates were also screened for removal of heavy metals with different concentrations (0–150 ppm) in liquid medium. Among 18 fungal cultures, 5 isolates were chosen for their high capability to tolerance of high concentration of heavy metals (150 ppm), and it was found that the fungal growth was promoted in the presence of U, Cr5+ Cu++ for FR1 (0.026, 0.133 and 0.128 g/100 ml), Cr5+ for FR7 (0.246 g/100 ml), Zn++, Co++ and Pb++ for FR13 (0.219, 0.371 and 0.303 g/100 ml), U for FR15 (0.174 g/100 ml) and Zn++, Co++ and Pb++ for FR16 (0. 203, 0.385 and 0.312 g/100 ml). These isolates FR1 & FR7, FR13, FR15 & FR16 belong to genus Aspergillus as identified by their morphological properties, respectively.