Lipase-catalyzed acidolysis of olive oil and caprylic acid in a bench-scale packed bed bioreactor

Abstract

Lipase-catalyzed acidolysis of olive oil and caprylic acid was performed in a bench-scale packed bed bioreactor to produce structured lipids (SL). A 1,3-specific lipase, IM 60 from Rhizomucor miehei was used as the biocatalyst. Reaction products were analyzed by reversed phase high-performance liquid chromatography, with an evaporative light scattering detector. Olive oil is characterized by four major clusters of triacylglycerol species with equivalent carbon number (ECN), C44, C46, C48, and C50. Three monosubstituted products and two disubstituted products were detected after the reaction. Monosubstituted products had ECN of C36, C38, and C40, and disubstituted products had ECN of C30 and C32. The effect of solvent, temperature, substrate mol ratio, and flow rate/residence time were studied. Optimal solvent-free production of SL was obtained at a substrate flow rate of 1 ml/min, residence time 2.7 h, temperature 60°C, and mol ratio 1:5 (olive oil/caprylic acid). Fatty acid distribution at the sn-2 position of olive oil was determined by pancreatic lipase hydrolysis as 74.8% oleic acid and 25.2% linoleic acid. SL produced at optimal conditions had 7.2% caprylic acid, 69.6% oleic acid, 21.7% linoleic acid and 1.5% palmitic acid at the sn-2 position.