Stearidonic acid (SDA) is a plant-based n-3 polyunsaturated fatty acid with multiple biological activities. The enrichment of SDA and synthesis of triacylglycerol (TAG) were carried out consecutively via two lipase-catalyzed reactions, hydrolysis, and esterification. First, SDA was enriched into a glyceride fraction from ahiflower seed oil by Candida rugosa lipase-catalyzed hydrolysis. Under the optimum conditions of 35°C, 0.1% lipase powder of Lipase OF, and 50% buffer solution (based on the weight of total substrate), SDA was enriched from 21.6 to 40.7 wt% in glyceride fraction. SDA-enriched TAG was then synthesized from the SDA-enriched glyceride and the SDA-enriched fatty acid via esterification using an in-house immobilized lipase as a biocatalyst. The SDA-enriched fatty acid was obtained from part of the SDA-enriched glyceride by saponification and the in-house immobilized lipase was prepared from Eversa® Transform 2.0 using Lewatit VP OC 1600 as a carrier. The optimum reaction conditions for the synthesis of TAG were a temperature of 50°C, an enzyme loading of 10%, and a vacuum of 10 mmHg. A maximum conversion to TAG of ca. 94% was achieved after 12 h under the optimum conditions.
Keywords: Candida rugosa; Eversa® transform 2.0; ahiflower seed oil; stearidonic acid; triacylglycerol.