Since the pioneering work of Martinek et al. [1] more than 30 years ago, numerous studies have been published, where enzymatic reactions were investigated in surfactant containing media. Most of them deal with reverse microemulsions, in which the enzyme is entrapped in water nanodroplets that are dispersed in an external oil pseudophase. Surfactants and cosurfactants stabilize the whole system by forming an interfacial layer between the aqueous and the hydrophobic part.