Nakyung Choi

Synthesis of α-linolenic acid-rich triacylglycerol using a newly prepared immobilized lipase

An α-linolenic acid (ALA)-rich triacylglycerol (TAG) was synthesized from an ALA-rich fatty acid (FA) from perilla oil and glycerol, using a newly prepared immobilized lipase under vacuum. The ALA-rich FA (purity >90wt%) used as the substrate was prepared by urea complexation from perilla oil FAs. Liquid Lipozyme TL 100L lipase from Thermomyces lanuginosus was used for immobilization. Nine different hydrophilic and hydrophobic carriers for immobilization were tested, and Duolite A568, which is a hydrophilic resin, was selected as the best carrier. This immobilized lipase was used to synthesize TAG by direct esterification under vacuum. The parameters investigated were temperature, enzyme loading, and vacuum level. The optimum reaction conditions were a temperature of 60°C, an enzyme loading of 15% (based on the total weight of the substrate), and a vacuum of 0.7kPa, respectively. The maximum conversion to TAG of ca. 88wt% was obtained in 12h under the optimum conditions.

Production of phytosteryl ester from echium oil in a recirculating packed bed reactor using an immobilized lipase

The synthesis of phytosteryl ester via the lipase-catalyzed esterification of phytosterol with fatty acid from echium oil was performed in a recirculating packed bed reactor. A commercial lipase from Candida rugosa was immobilized and then used to optimize the reaction conditions for the synthesis of the phytosteryl ester. The parameters investigated were temperature, molar ratio of phytosterol to fatty acid, retention time, and amount of solvent. The optimum conditions were determined as the temperature of 40℃, the molar ratio of 1:3 (phytosterol to fatty acid), the retention time of 3 min, and the solvent amount of 40 mL. The maximum conversion of phytosteryl ester was ca. 90 mol% under the optimum conditions. The major fatty acid in phytosteryl ester synthesized was α-linolenic acid (ca. 38 mol%).

Production of stearidonic acid-rich triacylglycerol via a two-step enzymatic esterification

The aim of this study was to synthesize stearidonic acid (SDA)-rich triacylglycerol (TAG) via a two-step lipase-catalyzed esterification under vacuum. SDA-rich fatty acid, which was prepared from echium oil via Candida rugosa lipase-catalyzed selective esterification, was used as the substrate. Two different immobilized lipases, Novozym 435 from Candida antarctica and Lipozyme TL IM from Thermomyces lanuginosus, were employed for the synthesis of SDA-rich TAG. In the first step, Novozym 435-catalyzed esterification of the SDA-rich fatty acid with glycerol was carried out for 2 h. In the second step, Lipozyme TL IM-catalyzed esterification of the reaction mixture from the first step was performed for an additional 10 h. The optimal reaction conditions for the second step were a temperature of 65 °C, an enzyme loading of 20%, and a vacuum of 0.7 kPa. Consequently, the maximum TAG conversion of ca. 86.4 wt% was obtained after 12 h via a two-step lipase-catalyzed esterification.

Synthesis of fatty acid methyl esters using mixed enzyme in a packed bed reactor

Fatty acid methyl esters were synthesized from palm fatty acid distillate (PFAD) and methanol in a packed bed reactor via lipase-catalyzed esterification. The PFAD consisted of 91 wt% of free fatty acids, 2 wt% monoacylglycerides, 3 wt% diacylglycerides, and 4 wt% triacylglycerides. t-Butanol was employed as a reaction medium and a mixed enzyme consisting of Lipozyme TL IM from Thermomyces lanuginosus and Novozym 435 from Candida antarctica was employed as the biocatalyst. The effect of mixed enzyme was investigated and the optimum blending ratio (w/w) of Novozym 435 to Lipozyme TL IM was 5:95. Using the mixed enzyme, the optimum molar ratio (PFAD to methanol) and temperature were determined to be 1:6 and 30°C, respectively. Under the optimized conditions, the maximum yield of ca. 96% was achieved.