Enrichment of ?-linolenic acid from fungal oil by lipase-catalysed reactions

Abstract

Various lipases have been evaluated as biocatalysts for the enrichment of γ-linolenic acid from a commercial fungal oil derived from Mucor sp. by selective esterification of the fungal oil fatty acids with n-butanol or by selective hydrolysis of the oil. Lipase from M. miehei (Lipozyme), as compared to lipases from Candida cylindracea, Penicillium cyclopium, and Rhizopus arrhizus, was found to be most effective in the enrichment of γ-linolenic acid in unesterified fatty acids upon esterification of the fungal oil fatty acids with n-butanol. Thus, the γ-linolenic acid content could be raised from 10.4% in the starting material to 68.8% in the unesterified fatty acids. Selective hydrolysis of the fungal oil triacyglycerols using Lipozyme resulted in about 1.5-fold enrichment of γ-linolenic acid in the unhydrolysed acylglycerols. Other lipases tested, such as those from P. cyclopium, C. cylindracea, R. arrhizus, Penicillium sp. (Lipase G), porcine pancreas and Chromobacterium viscosum, were also rather ineffective in the enrichment of γ-linolenic acid by selective hydrolysis of the fungal oil triacylglycerols.