Uptake of chromium by Aspergillus foetidus

Aspergillus foetidus has the ability to take up chromium during the stationary phase of growth and under growth-nonsupportive conditions. We observed a 97% decrease in hexavalent chromium (initial concentration 5 µg/g) at the end of 92 h of growth, which may be due to its reduction to Cr (III) and/or complexation with organic compounds released due to the metabolic activity of the fungus. Replacement culture studies under growth-nonsupportive conditions revealed that the maximum uptake of Cr (VI) at pH 7.0 is 2 mg/g of dry biomass. At low or high pH values, Cr (VI) uptake is significantly reduced. In addition, the initial rate of total chromium uptake is also enhanced by higher biomass concentrations and the presence of glucose. The results obtained through this investigation indicate the possibility of treating waste effluents containing hexavalent chromium using Aspergillus foetidus.