Applying β-cyclodextrin to amaranth inoculated with white-rot fungus for more efficient remediation of soil co-contaminated with Cd and BDE-209

Abstract

A pot experiment was conducted to investigate the effect of a series of β-cyclodextrin (β-CD) concentrations on bioremediation of soil co-contaminated with Cd and BDE-209 using amaranth and the white-rot fungus Phanerochaete chrysosporium, with BDE-209 degrading ability. Results showed that the white-rot fungus was beneficial to the growth of amaranth, Cd uptake and BDE-209 degradation. Addition of β-CD further increased biomass of both shoots and roots, shoot Cd concentrations and contents, chlorophyll concentrations and soil manganese peroxidase (MnP) activities. Furthermore, well-organized mesophyll cells were observed in β-CD treatments, implying that the combination of white-rot fungus and β-CD can alleviate the stresses of Cd and BDE-209 to mesophyll cells. The BDE-209 degradation rate was positively correlated to β-CD concentration and MnP activity in soil. Our results also revealed that RF+β0.8 treatment possessed the greatest Cd removal efficiency due to its well-configured mesophyll cells and the highest shoot biomass, chlorophyll concentration, and shoot Cd concentration. Considering simultaneous removal of Cd and BDE-209 from soil, using 0.8% β-CD to amaranth inoculated with white-rot fungus is a promising way forward for the phytoremediation of soil co-contaminated with Cd and BDE-209. A high percentage of mono-BDE was detected in inoculated amaranth, suggesting that BDE-209 was debrominated into low brominated PBDEs by the fungus in soil, which were then absorbed and further debrominated into mono-BDE in the plant.