Removal of metal ions from aqueous solutions by Penicillium biomass: Kinetic and uptake parameters

Abstract

The uptake and binding of Ni, Zn, Cd, and Pb by the mycelium of Penicillium digitatum are highly pH-sensitive, being severely inhibited below pH 3. In the case of Ni, Zn, and Cd, H⁺ inhibits competitively. The Cu-ion, like UO₂ ²⁺ studied previously, is nearly pH-insensitive. All of these cations except Pb are taken up to a greater extent by mycelial preparations preheated at 100° C for 5 min. Other activators include alkali and dimethyl sulfoxide (DMSO) pretreatment, but formaldehyde inhibits, Combining current and previous data, the ion-selective character of uptake is reflected, on a molar basis by the rank order Fe³⁺, Ni²⁺ Zn²⁺ > Cu²⁺ > Pb²⁺ UO₂ ²⁺ ≫ MoO₄ ²⁻. P. digitatum appears to act like a mixture of neutral and acidic glycans with no real evidence for cationic amino-functional sites. In addition to the technological applications in water treatment, we suggest that fungal biosorption may be of natural geochemical importance in the concentration of metals and formation of minerals.