Influence of zeolite PZC and pH on the immobilization of cytochrome c: A preliminary study regarding the preparation of new biomaterials

The adsorption of cytochrome c on to zeolite crystals and membranes with different chemical composition and structure was studied. The structure and texture of zeolite materials were identified by X-ray diffraction (XRD) and scanning electron microscopy (FESEM), while the variation of protein conformation was studied by Fourier transform infrared attenuated total reflectance (FTIR-ATR) analysis. In order to separate the influence of zeolite structures from the effect of composite membranes, a through analysis of the cytochrome c adsorption was performed on different crystals by varying several experimental parameters such as: pH value, protein amount, zeolite structures and chemical compositions. It is shown that the electrostatic type of interaction seems to be of the utmost importance to govern the immobilization, while the zeolite Brönsted acidity of the support is the subordinate parameter which differentiates the adsorption performances of different zeolite structures (that distinct for chemical composition of the framework).