Simultaneous reaction and separation in enzymatic hydrolysis of high oleate sunflower oil - evaluation of ultrafiltration performance and process synergy

An experimental study has been carried out on an integrated reaction system consisting of a stirred tank reactor, a de-emulsifier and an ultrafiltrati on (UF) unit for simultaneous reaction and product separation during the en zymatic hydrolysis of sun flower oil. The study focuses primarily on how UF performance and enzymatic activity are affected by different components in the reaction products and by the operating parameters of the integrated sy stem. An evaluation of the system productivity and synergistic relationship s between the kinetics of the hydrolytic reaction, de-emulsification, and p roduct separation is presented. The reaction system comprised a heterogeneo us oil/water system with the free enzyme functioning at the Liquid-liquid i nterface. In contrast to theoretical expectations, no significant gain in p roductivity and yield was observed in the operation of reaction and separat ion simultaneously. The continuous removal of the glycerol produced, surpri singly, resulted in only marginal improvements in overall reaction yield. T his may be explained by the complex mass transfer processes occurring at th e membrane/liquid interface and due to unsuccessful separation of the produ ced free fatty acids from both the de-emulsified aqueous and oil phases. Th e reactor operating parameters were also recorded including oil/water molar ratio and impeller stirring rate and their effect upon the UF flux perform ance and the stability of the lipase activity determined. (C) 1998 Elsevier Science S.A. All rights reserved.