Submitted to: Proceedings JOCS/AOCS World Congress
Publication Type: Proceedings
Publication Acceptance Date: 8/29/2002
Publication Date: 9/2/2002
Citation: Hosokawa, M., Brown, W.K., Hou, C.T. 2002. Formation of cyclic products from polyunsaturated fatty acids by clavibacter sp. ala2. Proceedings JOCS/AOCS World Congress. p. 36-41.
Technical Abstract: Purpose of experiment: Microbial transformation of unsaturated fatty acids to functional substances. In a previous study, Clavibacter sp. ALA2 was reported to convert linoleic acid into unique cyclic fatty acids such as diepoxy bicyclic fatty acids (DEOA) and tetrahydrofuranyl fatty acids (THFA) as well as trihydroxy fatty acids (THOA). In this presentation, we investigated bioconversion of n-3 and n-6 polyunsaturated fatty acids (PUFAs) by the ALA2 system. Methods: Bioconversions were carried out by adding a free fatty acid to a one-day-old culture (50 ml) and shaking at 200 rpm at 30 degrees C for 2-7days. Reaction products were detected and analyzed by GC, GC-MS and NMR. Results: Strain ALA2 produced the novel tetrahydrofuranyl fatty acids, 13,16- dihydroxy- 12,15-epoxy-9(Z)-octadecenoic acid and 7,13,16-trihydroxy-12,15-epoxy-9(Z)- octadecenoic acid from alpha-linolenic acid (18:3, n-3). The optimum incubation temperature was 30 degrees C for production of both THFAs. The total yield reached 67% after incubation of alpha-18:3 at 30 degrees C for 7 days. Strain ALA2 also converted icosapentaenoic acid (20:5, n-3) and docosahexaenoic acid (22:6, n-3) to 15,18- dihydroxy-14,17-epoxy-icosatrienoic acid and 17,20-dihydroxy-16,19-epoxy-4(Z), 7(Z),10(Z),13(Z)-docosatetraenoic acid. On the other hand, gamma-18:3 (n-6) and arachidonic acid (20:4, n-6) were converted to DEOA, THFA and THOA similar to linoleic acid as reported previously. Conclusions: Strain ALA2 biotransformed n-3 and n-6 PUFAs into different cyclic fatty acids with a hydroxyl group. Strain ALA2 converted n-3 PUFAs to THFAs, and n-6 PUFAs to DEOA, THFA and THOA.