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

The technical and economic feasibility of producing docosahexaenoic acid (D HA)- and eicosapentaenoic acid (EPA)-ethyl ester concentrates from transest erified tuna oil using supercritical fluid chromatography (SFC) was studied . A systematic experimental procedure was used to find the optimal values f or process parameters and the maximal production rate. DHA ester concentrat es up to 95 wt% purity were obtained in one chromatographic step with SFC, using CO2 as the mobile phase at 65 degrees C and 145 bar and octadecyl sil ane-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 b e simultaneously produced at the respective purities of 90 and 50 wt%. The process for producing 1,000 kg DHA concentrate and 410 kg EPA concentrate p er year requires 160 kg stationary phase and 2.6 tons/h carbon dioxide elua nt recycle. The SFC operating cost is U.S. $550/kg DHA and EPA ethyl ester concentrate.