Field production, purification and analysis of high-oleic acetyl-triacylglycerols from transgenic Camelina sativa

A diacylglycerol acetyltransferase, EaDAcT, from Euonymus alatus, synthesizes sn-3 acetyl triacylglycerols (acetyl-TAG) when expressed in Arabidopsis, Camelina and soybean. Compared to most vegetable oils, acetyl-TAGs have reduced viscosity and improved cold temperature properties that confer advantages in applications as biodegradable lubricants, food emulsifiers, plasticizers, and 'drop-in' fuels for some diesel engines. A high-oleic Camelina line was engineered to express the EaDAcT gene in order to produce acetyl-TAG oils with fatty acid compositions and physiochemical properties complementary to wild-type acetyl-TAG. The accumulation of acetyl-TAGs at 70 mol% of seed TAG in field-grown high-oleic Camelina had minor or no effect on seed weight, oil content, harvest index and seed yield. The total moles of TAG increased up to 27% reflecting the ability to synthesize more acetyl-TAG from the same supply of long-chain fatty acid. Acetyl-TAG could be separated from long-chain TAG by silica column or by reverse phase chromatography. The predominant acetyl-TAG molecular species produced in high-oleic Camelina was acetyl-dioleoyl-glycerol. The crystallization temperature of high-oleic acetyl-TAG (by differential scanning calorimetry at 1.0 degrees C/min) was reduced by 30 C compared to control TAG. The viscosity of high-oleic acetyl-TAG was 27% lower than TAG from the high-oleic control and:the caloric content was reduced by 5%. Field production of T4 and T5 transgenic plants yielded over 250 kg seeds for oil extraction and analysis. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.