Metal leaching from a spent catalyst by Alternaria alternata

The study evaluated the leaching ability of the extracellular medium produced by a fungus, which was identified as Alternaria alternata. The study included the selection of a culture medium that favored the organic acid and siderophore production; sucrose and Czapek media were evaluated. Once the culture media was selected, bioleaching study of the catalyst at 1 and 5% continued, using only the extracellular media incubating at 30° C, 150 rpm during 7 days. Results indicated that the extracellular media produced by A. alternata in sucrose media decreases pH from 6 to 4.8; in this media siderophores were also produced. The study of metal bioleaching, using the extracellular media, showed that metals were leached at different extent, and it was observed that catalyst concentration had an important effect on the metal removal and on the order of the removal. It was found that at 1% catalyst and after 48 h of treatment, the following metals were removed, in descending order, V> Al> Si> Mo > Mg> Fe> Ni> As> Cr. This is the first report on the metal removal from the catalyst by the extracellular media of A. alternata which opens new research alternatives for the treatment of hazardous wastes with high metallic content.