Extraction and properties of protein from camelina engineered to produce acetyl-triacylglycerols (camelina acetyl-TAG)

Authors: Hojilla-Evangelista, Milagros - Mila; Evangelista, Roque; OHLROGGE, JOHN - Michigan State University

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/22/2018
Publication Date: 5/6/2018
Citation: Hojilla-Evangelista, M.P., Evangelista, R.L., Ohlrogge, J. 2018. Extraction and properties of protein from camelina engineered to produce acetyl-triacylglycerols (camelina acetyl-TAG) [abstract]. American Oil Chemists' Society Annual Meeting and Expo, May 6-9, 2018, Minneapolis, MN. p. 15.

Interpretive Summary:

Technical Abstract: Camelina (Camelina sativa, Brassicaceae) has attracted interest for its seed oil as alternative feedstock for biofuels production. Researchers at Michigan State University successfully engineered camelina to produce seeds with oil containing high levels of acetyl-triacylglerol (acetyl-TAG) by incorporating the diacylglycerol acetyltransferase gene isolated from Burning Bush (Euonymus alatus). Acetyl-TAG has an acetyl group in the sn-3 position instead of the typical long-chain fatty acids found in vegetable oils. Acetyl-TAG would be beneficial as fuels, emulsifiers, plasticizers, biolubricants and hydraulic fluids. However, the impacts of such genetic modification on other components in camelina are unknown, especially the proteins, which are the likely major co-product of oil processing. This work, then, evaluated the composition, extractability and properties of protein in camelina acetyl-TAG press cake and compared them with those of wild camelina. Both ground, defatted camelina samples contained 45% crude protein. Major proteins were the NaCl, acetic acid, and water soluble fractions, which accounted for 40% of total protein. Camelina acetyl-TAG had more of the acid- and NaOH-soluble proteins. Electrophoresis showed notably different band patterns of ethanol, acid, and NaOH soluble proteins from wild and acetyl-TAG camelina. Conventional acid precipitation that we used previously for pennycress gave poor protein yields (< 5%), although camelina acetyl-TAG produced twice as much protein extract than did wild camelina. Modifying the extraction method (e.g. removal of precipitate solubilization step) resulted in more than 15% protein yield and improved protein purity (86% versus 72% crude protein) for camelina acetyl-TAG.