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item Hou, Ching

Submitted to: International Congress on Essential Fatty Acids and Eicosanoids
Publication Type: Proceedings
Publication Acceptance Date: 8/29/2002
Publication Date: 9/2/2002
Citation: Hou, C.T., Hosokawa, M., Iwasaki, Y. 2002. Bioconversion of unsaturated fatty acids to value-added functional products. International Congress on Essential Fatty Acids and Eicosanoids. p. 12-17.

Interpretive Summary: Previously, we discovered a new microbial strain ALA2 that produced seven new hydroxy fatty acid products from linoleic acid (a component of soybean oil). Hydroxy fatty acids are useful as starting materials for the synthesis of specialty chemicals, special military nylon, plastisizers, coatings and physiologically active agents. The new products have great potential to be used as bioactive agents and raw materials for synthesis of specialty chemicals. Application of these products either as agents for anti-plant pathogenic fungi or raw material for synthesis of specialty chemicals will benefit U.S. farmers.

Technical Abstract: Oxygenated metabolites of unsaturated fatty acids play a variety of important roles in biological systems. Previously, we reported the production of many novel oxygenated products from linoleic acid by Clavibacter sp. ALA2 enzyme system. They include: 12,13-dihydroxy-9Z-octadecenoic acid (12,13-DHOA), 12,13,17-trihydroxy-9Z-octadecenoic acid (12,13,17-THOA), 12:17; 13:17-diepoxy-9Z-octadecenoic acid (DEOA), 7-hydroxy-DEOA, and two tetrahydrofuranyl unsaturated fatty acids (THFAs). We found that strain ALA2 converted 12,13,17-THOA to DEOA and then to 7-hydroxy-DEOA. Therefore, 12,13,17-THOA is the intermediate for the production of diepoxy bicyclic fatty acids from linoleic acid. Recently, we found a compound and identified its structure by GC/MS as 12,13,16-trihydroxy-9Z-octadecenoic acid (12,13,16-THOA). This chemical structure is now confirmed by proton and carbon 13 NMR. This newly identified 12,13,16-THOA is a possible precursor in the formation of THFAs. Therefore, we used 12,13,16-THOA to investigate the biosynthetic pathway of THFAs. By using strain ALA2 cells and purified 12,13,16-THOA, we found that 12,13,16-THOA was converted to 12-hydroxy-THFA within 12 hours. We also found that 12,-hydroxy-THFA was converted to 7, 12-dihydroxy-THFA. Therefore, linoleic acid is metabolized by strain ALA2 enzymes through two distinct pathways, the major one is to produce DEOAs and the minor one is to produce THFAs. The branch point is 12,13-DHOA. Both DEOAs and THFAs are novel compounds and have potential biomedical applications.