Oxydation of oleic acid to (E)-10-hydroperoxy-8-octadecenoic and (E)-10-hydroxy-8-octadecenoic acids by Pseudomonas sp. 42A2.

Biotransformation of oleic acid with Pseudomonas sp. 42A2 has been found to produce(E)-10-hydroxy-8-octadecenoic acid (2a), (E)-10-hydroperoxy-8-octadecenoic acid (3a), and (E)-7,10-dihydroxy-8-octadecenoic acid (4a). Structures of the metabolites were fully characterized by infrared and 1H and 13C NMR spectra of the acids, by fast atom bombardment (FAB) and electron impact (EI) and chemical ionization (CI) mass spectrometry of the corresponding methyl esters. This is the first time that the two former compounds of trans stereochemistry have been described to have originated from a Pseudomonas sp. cell culture. Time course of products accumulation showed that biotransformation started with bacterial growth, the amount of products 2a (5.58 g/l) and 4a (2.63 g/l) being optimum after 24 h of incubation while hydroperoxide 3a (1.15 g/l) reached its maximum after 16 h of the biotransformation process. Experiments conducted to ascertain whether the conversion enzyme(s) was cell-bound or extracellular, showed that the enzyme(s) is cell bound, located in the periplasmic space and has lipoxygenase activity.