|Iwasaki, Yugo - USDA,ARS,NCAUR,PEORIA,IL|
Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 10, 2002
Publication Date: April 1, 2002
Citation: IWASAKI, Y., BROWN, W.K., HOU, C.T. BIOSYNTHETIC PATHWAY OF DIEPOXY BICYCLIC FATTY ACIDS FROM LINOLEIC ACID BY CLAVIBACTER SP. ALA2. JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY. 2002. V. 79. P. 369-372. Interpretive Summary: Previously, we discovered a new microbial strain ALA2 that produced seven polyhydroxy unsaturated fatty acids from linoleic acid. Hydroxy fatty acids are useful as starting materials for the synthesis of specialty chemicals, special military nylon, plastisizers, coatings and physiologically active agents. We have discovered different types of hydroxy fatty acids produced from converting vegetable oils by microbial enzymes. Now, we have established one of its biosynthetic pathways. 12,13,17-Trihydroxy unsaturated fatty acid was converted to diepoxy bicyclic unsaturated fatty acid and was then further converted to 7-hydroxy of the diepoxy bicyclic unsaturated fatty acid by strain ALA2. Trihydroxy fatty acids are known fungicides against many plant pathogenic fungi. The new products, diepoxy bicyclic unsaturated fatty acids 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 the US farmers.
Technical Abstract: Biosynthetic pathway of bicyclic fatty acids, 12:17,-13:17 -diepoxy-9-octadecenoic acid (DEOA) and 7-hydroxy-12:17,-13:17 -diepoxy-9-octadecenoic acid (hDEOA) by Clavibacter sp. ALA2 was investigated. When cultivated with linoleic acid as a substrate, the strain produced 12,13,17-trihydroxy-9-octadecenoic acid (THOA), DEOA and hDEOA as well as other fatty acids. To clarify the synthetic route to these bicyclic fatty acids, the strain was cultivated with purified THOA as a starting substrate. THOA was consumed almost completely by the strain with sequential generation of DEOA and hDEOA. Moreover, the strain produced hDEOA when cultivated with purified DEOA. Therefore, it was confirmed that THOA was a precursor of these bicyclic fatty acids, and that hDEOA was generated from DEOA. Based on our previously reported result that linoleic acid is first converted to 12,13-dihydroxy-9-octadecenoic acid (DHOA) and the present results, the overall biosynthetic pathway for the diepoxy bicyclic fatty acids from linoleic acid was postulated as: linoleic acid -> DHOA -> THOA -> DEOA -> hDEOA.