Process for Preparing Sterol Fatty Acid Esters with Enzyme

Abstract

The cholestrol esterase and lipase having the activity for, β-position of glyceride have synthetic activities of sterol-fatty acid esters and also have the ester interchange activities.
These reaction equilibrium of ester synthesis or ester interchange incline toward synthesis. Therefore the reaction proceed toward the synthesis even if the reaction system have many water. Because of this character, we are able to have some systems for sterol-fatty acid ester synthesis, the aqueous medium reaction system, the water containing organic solvent system and the organic solvent-water two-phase system.
Sterols having a hydroxyl group at the three position are available as alcoholic components.
The fatty acid components to be used include saturated fatty acids, unsaturated fatty acids, branched fatty acids, α-hydroxy fatty acids and dicarboxyl fatty acis having carbon atoms from three to twenty four and these esters of lower alcohol or glycerine.
Each outline of the reaction systems for industrial utilization (i.e. the continuous phase separation system with counter current liquid?liquid extractor, the continuous synthesis system by immobilized enzyme filled in a column and the air-lift reactor and the membrane reactor) are described.
The Air-lift reactor gave the many amounts of sterol ester per enzyme (ester/enzyme=1200 by weight) and high synthesis ratio of 99 % (wt %) at high substrates concentration of 69 % by continuous elimination of generated water with blowing nitrogen gas into the reaction mixture.
These reaction systems have developped and have reached a level to be able to use for industrial scale.