Location: Plant Polymer Research
2017 Annual Report
Objectives
The long-term objective of this project is to develop novel products utilizing current and new co-products from the industrial processing of agricultural materials. As a result our research will reduce dependence on non-renewable materials and produce higher value products that will benefit a large segment of our economy.
Objective 1: Enable, from a technological standpoint, the commercial production of marketable products from the proteins in crops such as pennycress, camelina, soybean, cottonseed or corn. Sub-objective 1A. Establish pilot-scale extraction and biorefining techniques that generate protein-rich industrial feedstocks from plant crops, such as pennycress, camelina, soybeans, or cottonseed.
Sub-objective 1B. Determine ability to form solvent cast and melt processed films or articles, as well as surface and interfacial tension agents; determine if suitable chemical modifications of these proteins will provide products that can replace petroleum-based products.
Approach
Establish pilot-scale extraction and biorefining techniques that generate protein-rich industrial feedstocks from plant crops, such as pennycress, camelina, soybeans, or cottonseed. Determine ability to form solvent cast and melt processed films or articles, as well as surface and interfacial tension agents. Determine if suitable chemical modifications of these proteins will provide products that can replace petroleum-based products.
Progress Report
Significant progress was made on both objectives which fall under National Program 306: Quality and Utilization of Agricultural Products, specifically Component 2, addressing Objective 1.3 of the ARS Strategic Plan. Under Sub-Objective 1A of this research project, numerous pilot-scale pennycress extractions were completed to produce pennycress protein isolate (PPI) using the industry standard acid precipitation approach. By incorporating a combination of technical (such as defatting) and mechanical (use of a high volume centrifuge) improvements, the yield and purity of PPI from pennycress protein presscake (PPC) were significantly improved. Five kilograms of defatted PPC produced more than 0.5kg of high purity protein isolate (PPI, 92%) at good yield (49%). These were both large increases over those of previous runs (80% and 30% respectively). Similar improvements were made in the industry standard saline extraction route to remove protein from the PPC, providing PPI of very high purity (99.9%) and good yield (48%). The PPI obtained from the saline approach was more soluble (~75%) than that obtained using the acid precipitation approach (40%). The PPI obtained from either extraction method was composed of eight major proteins with molecular weights between 6.4 and 41kDa. The solid material remaining after protein extraction (PSS) in addition to the PPC were valorized by incorporating into polylactic acid (PLA) using standard extrusion techniques. The PLA composites using the PPC had increased value (increased ductility) relative to control. As the amount of PSS was increased, the PLA composites had reduced in value (physical properties). The proteinaceous fraction in the PPC is believed to be the source for the improved properties observed when PPC was used relative to PSS in PLA blends.
Utilizing the high purity PPI obtained from the acid precipitation pilot process, films were prepared from formic acid solution. The films were homogeneous across their area with few defects. Glycerol is the preferred plasticizer and films having 15-20% glycerol had strengths of 14 and 9 megapascals – less than polypropylene but superior to other proteins. The elongation of these compositions was 12% and 87% respectively, the latter approaches that of polypropylene. At elevated humidity levels, strength decreases and elongation increases significantly. These large physical property changes are driven by water absorption as the pennycress films can absorb up to 35% moisture when stored at high humidity. The pennycress films are good oxygen barriers, superior to corn protein. The films are also reasonable water vapor barriers, being competitive with known food packaging films such as polyvinyl alcohol. As expected, with increased plasticizer, oxygen and water vapor permeability increase.
The use of protein and starch derivatives have been studied to protect plants from various pathogenic insects and microbes. Higher value blends have been produced using hexadecylammonium chloride amylose inclusion complexes (HexAM) and sodium palmitate amylose inclusion complexes with polyvinyl alcohol (PVOH). Quality PVOH blended films could be produced having from 10-50% of either complex. The blended films have increased bio-content, biodegradability, water resistance, and elongation with other properties being similar to control. Depending on which complex is chosen and the amount of complex being used, the properties of the blended film can be controlled. These marketable properties using an inexpensive readily commercializable material would be of value to PVOH producers. In a meeting with an US PVOH producer these results were shared. It has been found that when HexAM is applied to paper or cotton fabrics, the articles become more hydrophobic. An US patent application has been submitted regarding the use of HexAM in coating paper and cotton. When the HexAM coated articles have water applied to them, rather than being absorbed by the paper/cotton, the water will bead. In certain formulations, the water will evaporate before being absorbed by the paper. Two outgoing Material Transfer Research Agreement's (MTRA) were executed regarding the use of HexAM in providing higher value paper.
The production of zein based fibers using the electrospinning technique was pioneered in this lab. In cooperation with a collaborator, electrospun zein fibers were incorporated into gluten free bread dough formulations. The flow properties of the dough having zein fibers were improved. The resulting doughs were converted into bread and again the bread properties demonstrated the value of incorporating zein fibers. The bread loaves had higher volume and good cell size. Based on these results, a National Institute of Food and Agriculture grant was applied for and received to carry out additional research at the collaborator facility and at the ARS in Peoria, Illinois, to determine the ability electrospun zein fiber has to replace gluten in bread dough to create quality gluten free bread. An outgoing MTRA was prepared regarding this technology.
Camelina has been shown to have promise as a biodiesel source. In order to obtain the most value from this crop, a genetically modified camelina was produced which provided an improved oil which would result in a higher quality biodiesel and biobased lubricants and emulsifiers. The impact of this genetic modification on the proteinaceous components of this modified camelina must be determined in order to define the overall value of the modified plant. Lab extractions were carried out on the ground seed and it was found that the protein which was extracted using saline was the most abundant protein in both the wild and modified camelina plants. The modified camelina variety had double the amount of acid or base soluble protein relative to the wild camelina. Overall, the modified camelina seeds produced twice as much protein relative to the wild type and the modified camelinaprotein isolated was 15% more pure than that obtained from the wild type. The difference in size and type of proteins between the wild camelina and genetically modified camelina, as determined by examination of their electrophoretic patterns, was minimal.
Accomplishments
1. Improved water resistant paper and cotton articles. There are numerous routes to produce water resistant paper or cotton fabrics, however, these approaches typically use petroleum-based hazardous chemicals. Agricultural Research Service scientists in Peoria, Illinois, have found that cellulosic articles, such as paper or cotton fabrics, can have dramatically increased water resistance by applying certain starch complexes to them. The degree of improvement is such that an applied water droplet may evaporate before soaking into the article. A US patent application has been filed covering this technology. This technology will be able to replace techniques which utilize hazardous chemicals and processes allowing for water resistant paper and cotton articles which will be less expensive and have a smaller carbon footprint. These new products will result in new applications for corn starch and allow new markets for paper and cotton articles, benefiting producers and processors.
2. High starch content polymer blends. Polyvinyl alcohol (PVOH) is a petroleum-based high value/volume film with unique barrier properties. Agricultural Research Service scientists in Peoria, Illinois, have found that blends of PVOH with certain starch based complexes produced films with properties (elongation, water resistance, and oxygen barrier properties) equal or better than commercially available products and at lower cost. These product properties will allow these new starch-PVOH blends to participate in new markets. The starch complexes utilize commercially available inexpensive raw materials and are processed using industry standard techniques. In addition, by replacing a significant portion of a petroleum based product with up to 50% biobased material, the product and process are much greener and highly biodegradable.
Review Publications
Boddu, V.M., Paul, T., Page, M.A., Byl, C., Ward, L., Ruan, J. 2016. Gray water recycle: Effect of pretreatment technologies on low pressure reverse osmosis treatment. Journal of Environmental Chemical Engineering. 4:4435-4443.
Hay, W.T., Behle, R.W., Fanta, G.F., Felker, F.C., Peterson, S.C., Selling, G.W. 2016. Effect of spray drying on the properties of amylose-hexadecylammonium chloride inclusion complexes. Carbohydrate Polymers. 157:1050-1056. doi: 10.1016/j.carbpol.2016.10.068.
Hojilla-Evangelista, M.P., Evangelista, R.L. 2017. Effects of steam distillation and screw-pressing on extraction, composition and functional properties of protein in dehulled coriander (Coriandrum sativum L.). Journal of the American Oil Chemists' Society. 94(2):315-324.
Hay, W.T., Fanta, G.F., Byars, J.A., Selling, G.W. 2017. Rheological characterization of solutions and thin films made from amylose-hexadecylammonium chloride inclusion complexes and polyvinyl alcohol. Carbohydrate Polymers. 161:140-148.
Fanta, G.F., Felker, F.C., Hay, W.T., Selling, G.W. 2017. Increased water resistance of paper treated with amylose-fatty ammonium salt inclusion complexes. Industrial Crops and Products. 105:231-237.
Hay, W.T., Bihmidine, S., Mutlu, N., Weeks, D.P., Clemente, T.E., Long, S.P., Hoang, K.L., Awada, T. 2017. Enhancing soybean photosynthetic CO2 assimilation using a cyanobacterial membrane protein, ictB. Journal of Plant Physiology. 212: 58-68.
