Purification of polyunsaturated fatty acid esters from tuna oil with supercritical fluid chromatography

Abstract

Abstract The technical and economic feasibility of producing docosahexaenoic acid (DHA)‐ and eicosapentaenoic acid (EPA)‐ethyl ester concentrates from transesterified tuna oil using supercritical fluid chromatography (SFC) was studied. A systematic experimental procedure was used to find the optimal values for process parameters and the maximal production rate. DHA ester concentrates up to 95 wt% purity were obtained in one chromatographic step with SFC, using CO 2 as the mobile phase at 65°C and 145 bar and octadecyl silane‐type reversed‐phase silica as the stationary phase. DHA ester, 0.85 g/(kg stationary phase · h) and 0.23 g EPA ester/(kg stationary phase · h) can be simutaneously produced at the respective purities of 90 and 50 wt%. The process for producing 1,000 kg DHA concentrate and 410 kg EPA concentrate per year requires 160 kg stationary phase and 2.6 tons/h carbon dioxide eluant recycle. The SFC operating cost is U.S. $550/kg DHA and EPA ethyl ester concentrate.