STUDY AND COMPARISON OF 2 ENZYME MEMBRANE REACTORS FOR FATTY-ACIDS AND GLYCEROL PRODUCTION

Two enzyme membrane reactors (EMR), (i) with one substrate (olive oil) in an oil-in-water emulsion (E-EMR) and (ii) with two separated liquid phases (oil and water) (TSLP-EMR), have been studied for the conversion of the triglycerides to fatty acids and glycerol. The enzyme was Candida cylindracea lipase confined on the pressurized face or entrapped in the sponge side of capillary ultrafiltration membranes. Two methods for immobilizing the enzyme in the TSLP-EMR were used: ultrafiltration on a virgin membrane and ultrafiltration on glutaraldehyde pretreated membranes. A multiple use of the reactor was obtained immobilizing the enzyme on the membrane preactivated with glutaraldehyde. The TSLP-EMR showed a specific activity of 0.529 mmol/(mg.h) versus a specific activity of 0.170 mmol/(mg.h) of the E-EMR. The rate of fatty acid production in the TSLP-EMR was linear with time showing no enzyme deactivation in an operating time of 80 h. The kinetics observed in the two reactors was different: an equilibrium reaction product-inhibited for the E-EMR and an apparent irreversible reaction of zero order for the TSLP-EMR. Taking into account that in the TSLP-EMR, compared to the E-EMR, (i) the specific activity was higher, (ii) the specific rate was constant with the time, and (iii) the two products were already separated after the reaction, the TSLP-EMR configuration seems the more convenient.