Phospholipase C-catalyzed sphingomyelin hydrolysis in a membrane reactor for ceramide production

A membrane reactor for the production of ceramide through sphingomyelin hydrolysis with phospholipase C from Clostridium perfringens was studied for the first time. Ceramide has raised a large interest as an active component in both pharmaceutical and cosmetic industry. The enzymatic hydrolysis of sphingomyelin has been proven to be a feasible method to produce ceramide. In the membrane reactor constructed, the aqueous phase and the organic phase were separated by a membrane containing the immobilized enzyme, while the organic phase was continuously circulated. Among the 10 selected membranes, the enzyme immobilized in membrane RC 70PP had low immobilization efficiency, but retained the highest catalytic activity. Three immobilization methods, i.e. filtration (adsorption/entrapment), covalent binding, and cross-linking, were compared. The enzyme immobilized by filtration had the highest activity even under the low fixation level (9.4%). The optimal flow rate of the organic phase was 5 ml/min. High initial enzyme amount in the immobilization led to the decrease in the fixation level. Both the initial reaction rate and the specific activity of the enzyme increased with increasing enzyme loading, and slightly decreased after the immobilized enzyme amount over 50 μg in 9.6 cm2 membrane area. The immobilized enzyme retained 16% of the original activity after five cycles. Finally, the liquid enzyme, the enzyme immobilized on particle carriers, and the enzyme immobilized in the membrane were compared. The study demonstrated the improved enzyme reusability, the fast immobilization process, the straightforward up-scaling and the combination of the hydrolysis with the product separation in the membrane reactor developed.