Feasibility of cheese whey as an energy source for the growth of Aspergillus sp. and for the removal of heavy metals in batch reactor

Abstract

A B S T R A C TIn the present work, batch biosorption of Cu, Zn, and Ni ions by Aspergillus sp. was investigated. The effect of initial metal ion concentration (0-500 mg/l), pH (2.0-6.0), inoculum concentration (v/v), and different concentrations of total sugar in cheese whey (2, 4, 6, 8, and 10 g/l) on the biosorption of Cu, Zn, and Ni was studied separately. In the absence of metals and at pH 5, a maximum concentration of 5.62 g/l of biomass was observed. However, a decrease in the concentration of biomass was observed in the presence of Cu, Zn, and Ni. The concentration of Cu, Zn, and Ni was increased from 50 to 500 mg/l, and the maximum specific uptake was found to be 9.4 ± 0.15-62.2 ± 0.20 mg/g, 9.5 ± 0.1-64.0 ± 0.25 mg/g, and 7.2 ± 0.2-29.43 ± 0.08 mg/g, respectively. The biomass concentration increases with the increase in total sugar concentration in cheese whey. Scanning electron microscopy and X-ray Energy Dispersion Analysis depicted the possible cell-metal ions interaction.