Bioconversion of unsaturated fatty acids by Pseudomonas aeruginosa PR3

Our aim is to convert surplus vegetable oil and component fatty acids to value-added products using intact microbial cells. Among several useful bioconversion systems discovered, strain PR3 was further characterized. Strain PR3 was identified as Pseudomonas aeruginosa showing small-rod shape, Gram-negative, and motile with multiple polar flagellae. The microorganism converts oleic acid and ricinoleic acid to new, novel compounds with good yields. It converts oleic acid to 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). The reaction requires manganese indicating that certain enzyme, such as cytochrome P-450 class, may be involved. During the bioconversion, small amounts of 10-hydroxy-8-octadecenoic acid are present, and high production of phenazine 1-carboxylic acid is associated with low DOD accumulation. Strain PR3 converts ricinoleic acid to 7,10,12-trihydroxy-8(E)-octadecenoic acid (TOD) through a similar reaction mechanism of DOD formation. DOD and TOD are related to both pH and the culture medium for maximum yield and they can be further metabolized by strain PR3. The formation of DOD and TOD is unique in that it invloves a hydration and a hydroxylation at two positions and a rearrangement of the double bond of the substrate molecule. The potential uses of DOD and TOD are discussed. The potential biological activities of TOD are currently under investigation.