Biosorption Potential of the Aspergillus sp. and Insights into Secondary Metabolism in the Presence of Copper and Lead

Abstract

The fungus Aspergillus sp. was isolated from copper mining rejects and cultured in a liquid culture medium (potato dextrose, PD) enriched with CuSO 4 .5H 2 O and Pb(NO 3) 2 in different concentrations. By flame atomic absorption spectrometry (FAAS) it was observed that fungus absorbed 86% of both copper and lead, with initial concentrations of 100, 500 and 1000 mg L-1. The additional results provided by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction showed ability of the microorganism to act as a biosorbent as well as its capacity to transform the tested salts into other inorganic compounds. Chromatographic profile comparison of extracts obtained from the biotic, abiotic control and the cultivation enriched with the metals showed changes in the profile of the secondary metabolism. When the copper and lead salts were tested separately, there was an increase in the production of the compounds as function of the increase of the concentration and when associated promoted the decrease and disappearance of some substances produced by Aspergillus sp.