12 July 2005
Researchers at the US Department of Agriculture’s Eastern Regional Research Center (ERRC) are working to develop specialized variants of barley that could be used in ethanol production.
In the US, most ethanol is corn-based—and hence most production facilities are located in the Corn Belt, not on either of the coasts. Barley, the reasoning goes, grows well in areas where corn does not, and so might become a financially cost-effective ethanol feedstock, once a number of severely limiting problems are solved.
Barley has an abrasive hull that causes expensive wear and tear on grain handling and milling equipment. Furthermore, it has a much lower starch content than corn&mash;50%–55% to corn’s 72%. As starch is the starting point of the production process, the production yield would be much lower.
On top of that, the beta-glucan polysaccharide in barley makes the mash too viscous to mix, ferment and distill economically.
Accordingly, the ARS researchers are working to develop:
Hull-less barley varieties suitable for ethanol production.
New milling processes that separate barley kernels into a starch-enriched fraction for ethanol production and a protein- and fiber-enriched fraction for food and feed co-products.
A process that uses beta-glucanase enzymes in fermentation to dramatically break down high-viscosity beta-glucans into low-viscosity oligosaccharides, solving the beta-glucan problem.
ERRC researchers examined more than 100 new lines of barley being developed by collaborators at Virginia Polytechnic Institute and State University for suitability in ethanol production and have narrowed their focus to several promising varieties. Lines being developed at the ARS Small Grains and Potato Germplasm Research Unit in Aberdeen, Idaho, are also being evaluated.
Most barley not selected for brewing is used in animal feed and sells for well under $2 a bushel, according to the USDA. Barley farmers would like to see a higher return for their crop.
But although the research is at too early a stage to begin formulating a solid life cycle analysis (LCA) of the energy and emissions costs going into barley ethanol, the energy economics of barley farming would have to be much better than that of corn cultivation for this approach to make sense from that energy life-cycle point of view.
Given that the LCA benefits of cellulosic ethanol far exceed those of ethanol produced by fermenting harvested grain, it seems that the optimal ethanol solution for the coasts would be focusing on developing the cellulosic production processes, rather than working to produce another specialized crop-based feedstock.
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