In the present report, physically adsorbed rat liver microsomes were used in order to optimize the immobilization of membrane proteins on solid surfaces for use in biosensing and microreactor applications. Physical adsorption was used to form thin films on solid supports (gold, mica, macroporous aluminum oxide membrane). The characterization of the films was performed by surface plasmon resonance (SPR), atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM). Commercially available macroporous aluminium oxide membranes with a high surface area, allow the retention of a high amount of microsomal membranes in the form of a thin film. Microsomal film functionality was tested by monitoring the activities of several enzymes of phases I and II. Microsomal modified supports can be re-utilized for the same or different substrate after washing with appropriate buffer.