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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Bio-oils Research » Research » Publications at this Location » Publication #285953

Title: Biochemical conversion of oleic acid into estolides and their physical property evaluation

Author
item MARTIN-ARJOL, IGNACIO - University Of Barcelona
item MANRESA, ANGELS - University Of Barcelona
item Isbell, Terry

Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/2012
Publication Date: 11/12/2012
Citation: Martin-Arjol, I., Manresa, A., Isbell, T. 2012. Biochemical conversion of oleic acid into estolides and their physical property evaluation [abstract]. Association for the Advancement of Industrial Crops Conference, November 12-15, 2012, Sonoma, CA.

Interpretive Summary:

Technical Abstract: Sources of hydroxylated fatty acids (HFA) have significant importance in the development of many industrial chemicals and lubricants. The main commercial source of HFAs is derived from castor oil which has limited supplies due to a number of agronomic issues with this crop. Alternative sources of HFAs either through alternative crops that produce hydroxy oils or through synthesis from other commodity vegetable oils would be of interest to this industry. Direct hydroxylation of olefins has proved difficult and epoxy fatty acid ring opening results in hydoxylated moieties that are susceptible to dehydration or contain other undesirable adjacent functionality. Conversion of unsaturated fatty acids into HFAs using fermentation processes show some promise in making mono- and di-hydroxy compounds that could be used in further chemical derivitizations. When Pseudomonas aeruginosa 42A2 is cultivated in a mineral medium using oleic acid (20 g . l-1) as a carbon source in a bioreactor at 30 deg C, two different HFAs are produced with a conversion yield of 89% based on the oleic acid substrate. At the end of the cultivation process, 10(S)-hydroxy-8(E)-octadecenoic acid ((10S)-HOME) and 7,10(S,S)-dihydroxy-8(E)-octadecenoic acid ((7S,10S)-DiHOME) are extracted from the supernatant with ethyl acetate. Purification of (10S)-HOME and (7S,10S)-DiHOME was carried out by flash-chromatography in a normal phase column, obtaining (10S)-HOME and (7S,10S)-DiHOME with a purity of 91 and 96%, respectively. For the first time, an apolar organic media, n-hexane, was used to produce estolides from (10S)-HOME with an immobilized lipase from Candida antarctica, Novozyme 435, with a 30% reaction yield. The amounts of lipase and substrate were optimized as well as the reusability of the enzyme. Structural determination of the products produced in-vitro was carried out by LC-MS, MALDI-TOF MS and NMR. These structural techniques determined that enzymatically synthesized estolides were formed by two units of (10S)-HOME. Lastly, the estolides resulting from these syntheses were evaluated as potential lubricants by measuring their basic physical properties of pour point, cloud point, viscosity and oxidative stability.