Enzymatic production of ceramide from sphingomyelin

Ceramide and ceramide derivatives have raised a large interest as active components in both pharmaceutical and cosmetic industry. This interest is based on the fact that ceramide is a highly potent intracellular signalling lipid, involved in the regulation of apoptosis, cell differentiation, transformation and proliferation as well as metabolic regulation. Ceramide is also the main component of the stratum corneum intercellular lipids in the skin and is essential for its water-barrier function. Furthermore, liposomes containing high concentrations of natural ceramides have antitumor activity in vivo and recent results indicate that these liposomes can be used as an effective strategy for diminishing breast and lung cancer tumors. Studies also show that topical mixtures of stratum corneum lipids, dominated by ceramide, are highly efficient in repairing water-barrier function in children suffering from childhood atopic dermatitis. In the cosmetic industry, formulations using ceramide, as a moisture-retaining ingredient is a rapidly growing segment. It is claimed that these products dramatically increase skin's hydration level, repair the cutaneous barrier and prevent vital moisture loss, and contribute to reducing dry flaky skin and aged appearance.

Hence, there is a growing market for ceramide and this market is founded on high-value products. Chemical synthesis of ceramide is complex and expensive. Therefore, there is a large interest in obtaining ceramide from other sources, for example through hydrolysis of sphingomyelin (SM).

SM is one of the dominating phospholipids in bovine milk and in dairy by-products. The phospholipid fraction in whey contains about 30% SM. Since SM contains a ceramide moiety, whey phospholipids could be a safe and convenient source of ceramide. Hence, enzymatic production of ceramide from dairy phospholipids represents a promising system for a safe production of ceramide. However, this requires the development of efficient and scalable enzyme-based processes for hydrolysis of the phosphodiester bond between ceramide and phosphorylcholine, as well as cost-effective purification of ceramide from the other components of the starting fraction.

The modification site for production of ceramide from SM is the bond between the primary hydroxyl group of ceramide and phosphorylcholine. Since this bond cannot be specifically broken using chemical hydrolysis, an enzyme-based method must be used. Potential enzymes for cleaving the phosphodiester bond are Sphingomyelinase (SMase) and phospholipase C (PLC).

Establishing a profitable enzymatic production of ceramide from sphingomyelin probably requires an enzyme with a high catalytic activity on SM, but relatively low activity on other phospholipids. No previous work has been made concerning this development.