Immobilized lipase-mediated acidolysis of butteroil with conjugated linoleic acid: batch reactor and packed bed reactor studies

Six commercial lipases, in either free or immobilized forms, were screened for their ability to catalyze acyl exchange between the triacylglycerols of butteroil (milkfat) and conjugated linoleic acid (CLA) in an organic solve nt-free medium. Immobilized lipase preparations from Candida antarctica and Mucor miehei demonstrated the ability to increase the CLA content of the m ilk fat acylglycerols from the native value of 0.6 g/100 g fat to values wh ich were at least an order of magnitude higher. Comparable increases were a lso obtained with a free enzyme from Candida rugosa. In addition to the screening studies, the effects of the weight ratio of mi lkfat to CLA on the product distribution and of the water content on the ki netics and maximum extent of this acidolysis reaction were systematically i nvestigated in a batch reactor: The fatty acids liberated from the butteroi l triacylglycerols were primarily short chain fatty acids, especially butyr ic and caproic acids. Modified butteroils were also produced via acidolysis of butteroil with CLA in a packed bed reactor containing an immobilized lipase preparation from C. antarctica. Significant enrichment of the buberoil in CLA residues was a ccomplished at reactor space times (fluid residence times) of 2-4 h at 40-6 0 degreesC. Under these conditions, approximately 80-90% of the free CLA fe d to the reactor is (inter)esterified. (C) 2001 Elsevier Science B.V. All r ights reserved.