A hybrid membrane-emulsion reactor for the enzymatic hydrolysis of lipids

A hybrid reactor, consisting of a stirred vessel, a hydrophilic membrane loop and a hydrophobic membrane loop, is presented for the continuous enzymatic hydrolysis of soybean oil in an emulsion. The permeates of the hydrophilic and the hydrophobic membrane consist of a single water phase and a single lipid phase, respectively. No lipase activity could be detected in the permeates of both membranes, which implies that all enzyme is retained in the system. An important advantage of this system is that it combines the high surface area in an emulsion with the containment of lipase in a membrane reactor. It is further shown that the stability of the system can be improved considerably by the addition of CaCl₂ to the water phase. Under comparable conditions the enzyme stability in the hybrid reactor is lower than the stability in a stirred vessel. The composition of the emulsion appears to influence the flux of the membranes. The flux of the hydrophobic membrane increases with an increasing oil fraction of the emulsion while the flux of the hydrophilic membrane has an optimum for two different oil fractions—0 and 0.55 (v/v).