Bioaccumulation of chromium(VI), copper(II) and nickel(II) ions by growing Rhizopus arrhizus

The metal resistance capacity and metal ion accumulation capacity during the growth of Rhizopus arrhizus and the inhibition kinetics of heavy metals, namely chromium, copper and nickel were studied in a batch reactor. A maximum percentage uptake yield of 93.84, 95.52 and 61.44% were found for 25 mg/l of initial metal ion concentrations of chromium, copper and nickel, respectively. A maximum biomass of 20.17 g/l was obtained at 20 g/l of initial dextrose concentration and in absence of heavy metals. The inhibition was found to be a competitive inhibition for the bioaccumulation of chromium. Lineweaver–Burk plot, Aiba model and Bazua and Wilke models were used to study the inhibition kinetics of bioaccumulation of heavy metals chromium, copper and nickel using R. arrhizus and the model parameters were evaluated using experimental data.