Conversion of arachidonic acid into 14,15,19-trihydroxyeicosa-5,8,11-trienoic acid by Torula dematia NBRC 6213

Lipids are one of the three major nutrients that play important roles as sources of energy and as components of cell membranes. Fatty acid metabolites exhibit physiological activities. Among fatty acid metabolites, some hydroxy arachidonic acids (ARAs) have bioactive functions. In this study, we found that Torula dematia NBRC 6213 converts ARA into unknown fatty acids. Liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry, and nuclear magnetic resonance (NMR) analyses were conducted to identify this unknown fatty acid. The unknown fatty acid was identified as 14,15,19-trihydroxyeicosa-5,8,11-trienoic acid. Its production was maximized when T. dematia was cultivated in potato dextrose broth (PDB) medium and reacted for 12 h at pH 7.0 and 28 °C. In addition, multiple intermediates were formed during the conversion of ARA to 14,15,19-trihydroxyeicosa-5,8,11-trienoic acid. LC-MS analysis revealed molecular weights of 320, 336, and 338. This suggests that ARA conversion occurs via the hydroxylation, epoxidation, and hydrolysis of the epoxy group. T. dematia also converts other unsaturated fatty acids into similarly oxidized fatty acids.