Hydrolysis of olive oil by immobilized lipase from candida rugosa in reverse phase system

Abstract

Biotechnological approach to the lipid-hydrolyzing systems has advantages over chemical process. Recently the conversion of lipid by lipase has been studied intensively. Most of the work on this conversion has been performed in the conventional emulsion system, which has so many drawbacks to be improved. Moreover, little attention has been paid to bioprocess engineering for this reaction system. Thus an attempt has been made to develop the appropriate bioreactor system to overcome the drawbacks. A reverse phase system was developed for the hydrolysis of lipid at high substrate concentration, where lipases were immobilized on the gel particles containing water and dispersed in the continuous solvent phase containing olive oil. Lipase from Candida rugosa was used because it lacks the stereospecificity of triglycerides and catalyzes the complete hydrolysis of several oils to free fatty acids and glycerol. Three supports such as Sephadex LH-20, Sephadex LH-60, and Amberlite XAD-7 are selected, which are capable of containing much water and being dispersed in organic solvent. Lipase was immobilized simply by adsorption on these supports. The binding of lipase to the supports reached equilibrium after 2 hr. Adsorption was consistentwith a Langmuir isotherm. It was found that the increase of temperature and ionic strength of buffer during the immobilization of lipase was disadvategeous because they resulted in reduction of available water for the hydrolysis of lipids. Lipase immobilized on swollen Sephadex LH-20 and Sephadex LH-60 could almost completely hydrolyze 60 % (v/v) olive oil in isooctane. Sephadex LH-20 was selected as the most appropriate support, since immobilized lipase on this gel showed the highest activity and long term storage stability even though it has a low immobilization efficiency. Kinetic analysis of the lipase catalyzed hydrolysis reaction was found to be possible in this system. Amount of fatty acids produced was linearly proportional up to t...