Effects of a Copper-Resistant Fungus on Copper Adsorption and Chemical Forms in Soils

Abstract

For bioremediation of copper-contaminated soils, it is essential to understand copper adsorption and chemical forms in soils related to microbes. In this study, a Penicillium strain, which can tolerate high copper concentrations up to 150 mmol l−1 Cu2+, was isolated from a copper mining area. The objective was to study effects of this fungus on copper adsorptions in solutions and chemical forms in soils. Results from lab experiments showed the maximum biosorptions occurred at 360 min with 6.15 and 15.08 mg g−1 biomass from the media with Cu2+ of 50 and 500 mg l−1, respectively. The copper was quickly adsorbed by the fungus within the contact time of the first 60 min. To characterize the adsorption process of copper, four types of kinetics models were used to fit the copper adsorption data vs. time. Among the kinetics models, the two-constant equation gave the best results, as indicated by the high coefficients of determination (R2 = 0.89) and high significance (p < 0.01). The addition of the fungal strain to autoclaved soil facilitated increases in concentrations of acid-soluble copper, copper bound to oxides, and of copper bound to organic matter (p < 0.05). However, the inoculation of Penicillium sp. A1 led to a decrease of water-soluble copper in the soil. The results suggested that Penicillium sp. A1 has the potential for bioremediation of copper-contaminated soils.