INTERESTERIFICATION REACTIONS CATALYZED BY A LIPASE IMMOBILIZED ON A HYDROPHOBIC SUPPORT

Bacterial lipase from Pseudomonas cepacia immobilized on a hydrophobic support was used to bring about the interesterification reactions of the triglycerides of olive oil with octanoic acid. When the lipase was immobilized on microporous polypropylene powder, the overall reaction rate was approximately seven times faster than that observed when the support was diatomaceous earth or when a comparable amount of free enzyme was present in the reaction mixture. At water contents of less than 1% by weight, an increase in the concentration of water resulted in faster rates of interesterification at the expense of a larger accumulation of intermediate hydrolysis products such as mono- and diglycerides. In the solventless interesterification reactions of octanoic acid and the triglycerides of olive oil, a higher ratio of octanoic acid to olive oil resulted in both faster initial rates of interesterification and eventually, as the mixture approached equilibrium, a higher fraction of octanoic acid residues in the glycerides of olive oil.