SUBSTRATE SPECIFICITIES OF LIPASES IN VIEW OF KINETIC RESOLUTION OF UNSATURATED FATTY-ACIDS

Several commercially available lipases have been evaluated with regard to their substrate specificity in the esterification of fatty acids h aving specific positions of cis double bonds, e.g. petroselinic acid ( n-12 18:1), alpha-linolenic acid (n-3 18:3), gamma-linolenic acid (n-6 18:3), stearidonic acid (n-3 18:4), dihomogamma-linolenic acid (n-6 2 0:3), eicosapentaenoic acid (n-3 20:5) and docosahexaenoic acid (n-3 2 2:6), with n-butanol. A common feature of most lipases, e.g. those fro m Penicillium cyclopium, Candida cylindracea, Mucor miehei, Rhizopus a rrhizus and Penicillium sp. is that fatty acids having the first doubl e bond from the carboxyl end as a cis-4 (n-3 22:6), cis-6 (n-12 18:1, n-6 18:3, n-3 18:4) or a cis-8 (n-6 20:3) double bond are strongly dis criminated against compared to the other fatty acids, such as myristic acid (14:0), the reference standard, and n-3 18:3. In the case of the lipase from porcine pancreas, however, the discrimination against the above fatty acids is not as strong as with the other lipases. In cont rast, the lipase from Chromobacterium viscosum shows a preference for n-12 18:1, n-6 18:3 and n-3 18:4. The observed substrate specificities can be utilized for enrichment of particular fatty acids by lipase-ca talysed kinetic resolution from fatty acid mixtures, derived from natu rally occurring fats and other lipids.