a method for producing bacteriorhodopsin - containing microcapsules is described , which can be optically activated , having a diameter of less than 50 μm , preferably less than 10 μm , comprising an enveloping layer , which protects the bacteriorhodopsin from harmful environmental factors , while at the same time preserving the functionality thereof . in doing so , bacteriorhodopsin is suspended in a first step , in the form of pm / br patches in an aqueous medium having a ph value ranging from 6 - 9 in the presence of a water - retaining polymer , and said suspension is spray - dried to form a powder , or is dried in an aliphatic solvent using low steam pressure and subsequent dehydration to form a powder . in a second step , the powder obtained in this way is provided with an envelope , which is substantially completely translucent to light in the visible range and made of a polymer and / or a paraffin having a solidification point ranging between 45 ° c . and 65 ° c . and / or a carnauba wax having a melting range of 70 - 90 ° c . furthermore , such microcapsules are described , and uses of such microcapsules .