7.10- dihydroxy-8 -octadecenoic acid production

It was reported earlier that strain ALA2 converted a-linolenic acid to 13,16-dihydroxy-12,15-epoxy-9(Z)-octadecenoic acid, and 7,13,16-trihydroxy-12,15-epoxy-9(Z)-octadecenoic acid (Hosokawa et aL, 2003b). From product structures obtained from the co-3 PUFAs EPA and DHA, it seems that strain ALA2 places hydroxyl groups at similar positions from the omega (co)-terminal end of the substrates and cyclizes them to related THF ring structures, despite their increased total carbon chain lengths (by 2 and 4 carbons, respectively) and numbers of double bonds (by 1 and 2 respectively). 

Figure 31.1. Schematic diagram of the production of 7,10-dihydroxy-8( T)-octadece-noic acid (DOD) from oleic acid by P. aeruginosa PR3. HOD represents 10(S)-hydroxy-8(E)-octadecenoic acid.

Hou et al. (1991) reported the discovery of a new compound, 7,10-dihydroxy-8( )-octadecenoic acid (DOD), which was produced from oleic acid at a greater than 60% yield by PR3. Maximum DOD production was achieved after 48 hour incubation under pH 7.0,30°C, and 150rpm shaking speed. The yield of DOD production by strain PR3 was improved to over 80% through modifying the culture medium and reaction parameters (Kuo et al., 1998).The production of a similar compound by Pseudomonas sp. 42A2 was reported and studied (De Andres et al., 1994 Mercade et al., 1988). 

According to the reports describing metabolic pathways involved in the conversion of linoleic acid to trihydroxy fatty acids, several intermediate reaction products, such as trihydroxy-, hydroperoxy-, dihydroxy-, and hydroxyepoxy-octadecenoate, were involved (Kato et al., 1984,1986). Those metabolites of linoleic acid showed distinct biological functions according to their intermediate structures, including mono-, di-, trihydroxy-octadecenoic acid, and hydroperoxy-, epoxy-forms (Kato et al., 1984 Blair, 2001 Gobel et al., 2002 Hou and Forman, 2000). In an effort to understand the overall mechanism involved in the varied biological functions of the complicated reaction metabolites of bio-converted polyunsaturated fatty acids, Kim et al. (2006) studied the oxidative activities on fish oil, of crude extracts produced by PR3 from... 

Bioconversion of 12,13,17-THOA and DEOA. For the biosynthesis of diepoxy bicyclic unsaturated fatty acid by strain ALA2, we predicted that linoleic acid is converted to 12,13-dihydroxy-9(Z)-octadecenoic acid (12,13-DHOA) and then is oxidized at C-17 to form 12,13,17-trihydroxy-9( -oc-tadecenoic acid. This compound is possibly cyclized to form diepoxy bicyclic products. To prove this cyclization step, we used purified 12,13,17-THOA as substrate. Figure 1 demon-... 

Strain PR3 converted oleic acid to a new compound, 7,10-dihydroxy-8( )-octadecenoic acid. The absolute configiuation of DOD was determined with the aid of circular dichroism to be R,R (33). The production of DOD from oleic acid reached a maximum after 48 h of incubation with a yield of 63%. Further incubation reduced DOD content in the medium, thus strain PR3 metabolizes DOD. 

Khare SK, Kumar A, Kuo TM. 2009. Lipase-catalyzed production of a bioactive fatty amide derivative of 7,10-dihydroxy-8( -octadecenoic acid. Bioresour Technol 100 1482-1485. 

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