Enhanced copper adsorption and morphological alterations of cells of copper-stressed Mucor rouxii

Fungi are ubiquitous and can become dominant in metal-polluted habitats. Some fungal strains are tolerant to metal toxicity. The presence of a high copper concentration in the culture medium induced morphological changes in the copper-tolerant strain of Mucor rouxii. Copper binding by strains of M. rouxii cultured at a trace (1.6 × 10−3 mM) copper concentration was less effective than those cultured at a high (3.2 mM) copper concentration. These experiments were performed at an optimum time of 30 min and a pH of 5 for Cu2+ binding. Our results suggest that a passive metal-binding mechanism makes the majority of total copper binding. These preliminary findings suggest that the presence of high levels of copper in the culture medium allow the development of chemical functional groups on the fungal surface, which led to an enhanced copper-binding ability and induced important morphological changes in M. rouxii.