Adsorption characteristics of Cd2+ by Agaricus bisporus (Large) mycelia, extracellular polymer substances and mycelial cell wall

Cadmium (Cd) is a highly toxic heavy metal and a major soil contaminant in China. The development of efficient remediation technologies remains a key research focus. Macrofungi-based remediation represents a promising strategy. This study investigated the Cd ²⁺ adsorption characteristics of Agaricus bisporus (Large) mycelia, extracellular polymeric substances (EPS), and cell wall. Results showed that Cd ²⁺ stress induced a hormetic response in EPS production and aitered EPS composition. All components displayed favorable Cd ²⁺ adsorption properties, with EPS exhibited an outstanding maximum adsorption capacity of 583.07 mg/g dry weight—tenfold higher than those of mycelia and cell wall. Adsorption kinetics of all components fitted the pseudo-second-order kinetic equation. Cd ²⁺ adsorption by EPS conformed to the Langmuir isotherm model, whereas mycelia and cell wall followed the Freundlich isotherm model. In conclusion, the high Cd ²⁺ binding capacities of EPS and cell walls constitute a potential key mechanism enabling A. bisporus to resist extracellular Cd stress and alleviate Cd toxicity.