Toxicity of Pristine and Chemically Functionalized Fullerenes to White Rot Fungus Phanerochaete chrysosporium

Fullerenes are widely produced and applied carbon nanomaterials that require a thorough investigation into their environmental hazards and risks. In this study, we compared the toxicity of pristine fullerene (C60) and carboxylated fullerene (C60-COOH) to white rot fungus Phanerochaete chrysosporium. The influence of fullerene on the weight increase, fibrous structure, ultrastructure, enzyme activity, and decomposition capability of P. chrysosporium was investigated to reflect the potential toxicity of fullerene. C60 did not change the fresh and dry weights of P. chrysosporium but C60-COOH inhibited the weight gain at high concentrations. Both C60 and C60-COOH destroyed the fibrous structure of the mycelia. The ultrastructure of P. chrysosporium was changed by C60-COOH. Pristine C60 did not affect the enzyme activity of the P. chrysosporium culture system while C60-COOH completely blocked the enzyme activity. Consequently, in the liquid culture, P. chrysosporium lost the decomposition activity at high C60-COOH concentrations. The decreased capability in degrading wood was observed for P. chrysosporium exposed to C60-COOH. Our results collectively indicate that chemical functionalization enhanced the toxicity of fullerene to white rot fungi and induced the loss of decomposition activity. The environmental risks of fullerene and its disturbance to the carbon cycle are discussed.