Location: Plant Polymer ResearchTitle: Pennycress protein isolate: Pilot plant production and application in films polymeric composites
Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/27/2017
Publication Date: 4/30/2017
Citation: Hojillaevangelist, M.P., Selling, G.W., Finkenstadt, V.L., Evangelista, R.L.Pennycress protein isolate: Pilot plant production and application in films polymeric composites. [Abstract]. Annual Meeting and Expo of the American Oil Chemists' Society. pg. 16.
Technical Abstract: This work scaled up the process of producing pennycress protein isolates (PPI) using 5 kg starting material (previously 100 g in bench-scale research). Defatted press cake, produced by prepressing and hexane extraction, was mixed with preheated 50 L of aqueous NaOH (pH 10) for 90 min in a jacketed kettle maintained at 50°C. Succeeding key steps involved centrifugation, supernatant collection, acid-precipitation (pH 4.0), dissolution of precipitate in pH 7.0 water, ultrafiltration-diafiltration, and freeze-drying. The process produced 0.5 kg PPI containing 92.1% crude protein, which calculates to ca. 30% protein recovery, an improvement over the bench-scale method’s 23% recovery. The current PPI still had 7 major polypeptides with MW 6-42 kDa and was least soluble (5% soluble proteins) at pH 5.5; but, its maximum solubility of 70% at pH 10 was markedly less than that of the lab-produced isolate. PPI films, produced using glycerol as plasticizer, were homogeneous and had good elongations (up to 170%) but low tensile strength (2-7 MPa). PPI showed negligible changes in structure during heating and ageing of films. Pennycress press cake or spent solids from protein extraction were combined with polylactide (PLA) to produce green polymer composites by melt extrusion. Resulting composites had reduced tensile strength and elongation as the pennycress portion was increased. Removal of pennycress soluble proteins led to less flexibility at both 10% and 25% wt/wt fill. Therefore, the observed significant improvement in ductility (strength and flexibility) was conclusively attributed to the pennycress protein component.