Loss of enzyme activity due to adsorption onto emulsion droplets

In order to study the possibility of immobilization of enzymes on a liquid carrier while retaining activity, we used hen's egg lysozyme (E.C. 3.2.1.17) and bovine chymosin (E.C. 3.4.23.4) as the emulsifying agents to make emulsions of soya oil in water. The enzymes were applied in three different ways: (i) mixed with the soya oil-water, then emulsified; (ii) immediately added to emulsions of soya oil made with bovine serum albumin in a range of concentrations; and (iii) simultaneous emulsification with an enzyme and bovine serum albumin in various concentration ratios. The extent of adsorption was determined in depletion studies. Enzyme activity in situ was determined using flexible small-molecular-weight substrates. It was found that every mode of emulsification led to complete in situ inactivation of the enzymes. Even after desorption of the enzymes by the surfactant Tween(C) 20 the enzymes proved to be inactivated; the surfactant itself caused no inactivation of the enzymes in solution.