Utilisation of hemicelluloses to form useful new biopolymers.
The overall objective is to obtain new polymers based on hemicelluloses derived from the Risø bioethanol process. Hemicelluloses are part of the lignocellulosic stream that is fermented in a multi-step process to generate bioethanol. However, the hemicelluloses are not necessarily all utilized in this process and may be available for other high-value uses. One possibility is to chemically modify these carbohydrates to make them more amenable to further processing (e.g., extrusion). There are reports in the literature of a few studies of this type; however, comprehensive investigations on the chemistry of hemicellulose modification, the properties of the modified hemicelluloses and their subsequent processing appear to be lacking. The use of hemicelluloses or hemicellulose fractions to form copolymers with other biopolymers is also planned as part of the programme.
New biopolymers from hemicelluloses are of interest because they fit with the increasing need in society for sustainable products from renewable sources. New materials could also potentially complement and improve the economics of the Risø bioethanol process. Target uses for the new biopolymers might range from high value (e.g. medical applications) to somewhat lower value applications (e.g. films for packaging).
Potential new uses for starch from barley
The overall objective is to diversify the products from barley. The basic idea is to establish a four-stage programme that would span activities ranging from barley plant genetics and plant breeding through starch extraction to the preparation and testing of a variety of new starch-based thermoplastic materials. In stage one, plant resources available at Risø will be used as starting material to obtain starches with varying chemical composition. These will include: 1) barley mutation lines with different ratios of amylose/amylopectin as well as wild types containing the “normal” 25% amylose and 75% amylopectin, 2) a large mutant population of barley, 3) a set of barley lines blocked in each of the genes in the biosynthesis of amylose/amylopectin, and 4) a large collection of barley lines including wild barley collected from Europe, Asia and Africa. In stage two, starch will be extracted from the starting plant materials and extruded or cast into films. Test procedures used to characterise the starch bioplastics will include mechanical property testing, permeability tests, thermal analysis and molecular weight determinations for amylose and amylopectin. In stage three, the focus will be on barley lines for which interesting starch properties have been found during stage two. Genes from these lines will be transferred into a genetic background that can deliver a reasonable starch yield with high disease resistance. Stage four will involve a more intensive study of starch bioplastics derived from the preferred barley lines.
As Denmark's largest agricultural crop, there is considerable interest in diversifying the range of products that can be obtained from barley and the Plant Research department at Risø has extensive experience in a wide range of issues associated with the genetics, growing and harvesting of barley.
Involved Risø Divisions
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