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United States Department of Agriculture

Agricultural Research Service

Title: Biotransformation of Linoleic Acid by Clavibacter Ala2: Isolation and Characterization of Bicyclic Fatty Acids

item Hou, Ching
item Gardner, Harold
item Weisleder, David
item Brown, Wanda

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: April 28, 2000
Publication Date: N/A

Technical Abstract: In our ongoing efforts to convert vegetable oils into value-added industrial products, we previously isolated a novel fatty acid, 12,13,17-trihydroxy-9(Z)-octadecenoic acid [gas chromatography-retention time (GC-RT) of 23 min], produced from linoleic acid by Clavibacter ALA2. This trihydroxy fatty acid showed anti-pathogenic fungal activity when applied to plants. In addition, there were four minor products with GC-RT of 7, 10, 13, and 17 min. A tetrahydrofuran-hydroxy fatty acid (GC-RT 10) and a tetrahydrofuran-dihydroxy fatty acid (GC-RT 17) were identified by GC/MS and microchemical methods [Hou et al. JAOCS 75: 1483-1487 (1998)], and their structures are now confirmed by NMR analysis. We have also isolated and characterized most of the remaining fatty acids by GC/MS, NMR, and microchemical methods. They were found to be novel bicyclic fatty acids, 12,17;13,17-diepoxy-9(z)- octadecenoic acid (GC-RT 7) and 12,17;13,17-diepoxy-7-hydroxy- 9(Z)-octadecenoic acid (GC-RT 13). An additional unknown was isolated (GC-RT 13) that had spectral features consistent with a 12,17;13,17- diepoxy-9(Z)-octadecenoic acid having one hydroxyl within the bicyclic ring. The pattern that emerges is hydroxylation at C-7 and hydroxylation/epoxide-cyclization at C-12, -13, -16, and -17. It is not known whether epoxidation or hydroxylation occurs first. The optimum conditions for biotransformation were 80 h at 30C and pH 6.0. The physiological activity of these novel fatty acids is under investigation.

Last Modified: 4/21/2015
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