This paper describes the characterization of gelatin-ceramic membranes grafted with laccase from Trametes versicolor for the degradation of pharmaceutical pollutants. Tetracycline was chosen as a model substrate to confirm the optimization of the grafting protocol using two kinds of microfiltration membranes with pore diameters equal to 0.2 and 1.4 mu m. The preparation of the enzymatic membranes was optimized by varying the concentrations of the enzyme and gelatin solutions used as well as by measurement of active support permeability. An immunogold labeling method coupled with scanning electron microscopy was applied for a first time to determine the spatial distribution of enzymes on the membranes. The amount and distribution of the grafted enzymes were then correlated with the tetracycline depletion observed with the enzymatic membranes. (C) 2014 Elsevier B.V. All rights reserved.