[Development of a laminar bioadsorbent with hypertolerant Phanerochaete chrysosporium to Cd, Ni and Pb for wastewater treatment].

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Citation abstract

BACKGROUND: The use of basidiomycetes for metal removal is an alternative to traditional methods. In this, the biomass acts as a natural ionic exchanger removing metals from solution.

OBJECTIVE: To develop a laminar biosorbent using a basidiomycete fungus resistant to high Cd, Ni and Pb concentrations.

METHODS: The tolerance of Trametes versicolor, Pleurotus ostreatus and Phanerochaete chrysosporium was evaluated using increasing concentrations of the heavy metal salts, cadmium sulphate, lead acetate and nickel chloride. A biosorbent system was developed based on polyethylene sheets with a fungal biomass. It was evaluated in bubble columns using synthetic wastewater with the 3 metal salts at a rate of 300 mg/l. Finally, in a complementary experiment using shake flasks, the effect of a higher amount of biomass related to the metal removal efficiency was evaluated.

RESULTS: P. chrysosporium strain was more tolerant to C₄H₆O₄Pb (10,000mg/l), Cl₂Ni (300mg/l) and CdSO₄·8H₂O (1,500 mg/l). In a reactor, under non-ligninolytic conditions, the fungus removed 69% of the chemical oxygen demand and produced enzymes such as LiP (0.01 U/l) and MnP (0.6 U/l.). An accumulation of metals in the wall was observed. By increasing the biomass to 1.6 (w/v), the metal biosorption was favored in the mixture (57% Pb, 74% Cd, and 98% Ni) and separately (95% Pb, 60% Cd, and 56% Ni). Competition between Ni and Pb by ligands of the wall was observed.

CONCLUSION: A novel laminar system based on P. chrysosporium viable biomass was developed. It has a large surface area and tolerance to high concentrations of Cd, Ni and Pb. It seems to be an alternative for the removal of metals from water.