Copper adsorption and removal from water by living mycelium of white-rot fungus Phanerochaete chrysosporium

Adsorption of copper cation (II) in aqueous solutions by living mycelium pellets of Phanerochaete chrysosporium was investigated to study the effects of metal concentration, pH, organic solvents and common cation. The maximum copper adsorption capacity of the fungal mycelium estimated with the Langmuir model was 3.9 mmol Cu per gram of dry mycelium compared with 1.04 mmol Cu per gram of a strong acidic ion-exchange resin. The living mycelium also showed a high affinity to copper in diluted solutions. The adsorption distribution coefficient (K) maintained a constant value around 1.6 l per gram of adsorbent in the solutions of up to 100 mg Cu/l. Ion-exchange of copper cations with fungal biomass accounted for a small part (<1%) of copper uptake by the fungal mycelium. The high capacity of copper uptake by living mycelium was mainly attributed to adsorption of very tiny colloids of copper hydroxide formed around pH 6, which was observed with scanning electron microscope and indicated by the pH effect on metal adsorption. Compared with an ion-exchange resin which showed a quite consistent adsorption capacity in a pH range of 2.5–5, the living fungal mycelium had an optimal adsorption capacity in a quite narrow pH range around 6. Copper adsorption and desorption on the fungal mycelium was easily repeated by controlling pH, a unique property of the fungal mycelium for continuous removal and recovery of copper cation from water. Organic solvents had little or positive effect on the copper adsorption capacity of living fungal hyphae.