1a. Objectives (from AD-416):
The overall objectives of this project are to develop economically viable technology to allow production of fuel ethanol from "Generation 1.5" regional non-corn feedstocks such as winter barley, that are grown outside the Corn Belt on fallow land or land that does not compete with food production. Evolve these ethanol plants into multiple product biorefineries, producing high value food and feeds and then into multi-feedstock biorefineries that can accept fermentable sugars from local lignocellulosic feedstock to produce additional ethanol and valuable coproducts. 1. In conjunction with CRADA partners and other collaborators, develop technologies that enable (1) commercially-preferred processes for converting winter barley into fuel ethanol in ways that significantly reduce biorefinery water usage and (2) commercially-viable, value-added co-products from barley-based biorefineries. 1a: Develop commercially-preferred processes for converting winter barley into fuel ethanol and improved DDGS in ways that increase ethanol yield and significantly reduce biorefinery water usage. 1b: Develop commercially-viable, value-added carbohydrate based co-products from barley kernels, hulls, and/or straw in barley-based biorefineries. 1c: Develop commercially-viable, value-added lipid based co-products from barley kernels, hulls, and/or straw in barley-based biorefineries. 2. In collaboration with NCAUR, develop technologies that enable the commercially-preferred conversion of barley hulls and/or straw into sugar-containing make-up water, allowing the production of ethanol from both starch and cellulose in a barley grain-based biorefinery.
1b. Approach (from AD-416):
In conjunction with CRADA partners and other collaborators, develop technologies that enable commercially-preferred processes for converting winter barley into fuel ethanol and improved DDGS in ways that increase ethanol yield and significantly reduce biorefinery water usage. Develop commercially-viable, value-added carbohydrate based co-products from barley kernels, hulls, and/or straw in barley-based biorefineries. Develop commercially-viable, value-added lipid based co-products from barley kernels, hulls, and/or straw in barley-based biorefineries. In collaboration with NCAUR and other partners, develop technologies that enable the commercially-preferred conversion of barley hulls and/or straw into sugar-containing make-up water, allowing the production of ethanol from both starch and cellulose in a barley grain-based biorefinery.
3. Progress Report:
Developed a high-solid fermentation process for barley ethanol production. This process uses the native enzymes that are present in the barley grains during a short incubation period (2 hours) at low temperature (60oC) to reduce the viscosity of the mash and allow use of high solid concentrations. We were able to use 35% solids (dry basis) and achieve almost 19% ethanol by volume (150 g/liter). All of these results were transferred to our CRADA partner. Cellulose-rich residues obtained by AHP extraction of barley straw and barley hulls were subjected to fed-batch simultaneous saccharification and fermentation (SSF) using the yeast Saccharomyces cerevisiae. Final ethanol concentrations of ~50 g/l were obtained. We also developed a process for obtaining fermentable sugars from barley hull and integration of these sugars in a barley biorefinery for production of ethanol by yeast (from glucose) and value-added co-products such as astaxanthin (from other sugars such as xylose). In collaboration with Iowa State University (ISU) optimum conditions of Soaking in Aqueous Ammonia (SAA) pretreatment of barley straw were determined. Pretreated barley straw was fractionated by commercial xylanase hydrolysis. The xylose-rich solutions were used for astaxanthin fermentation. The cellulose-rich residue was subjected to fed-batch SSF fermentation using the yeast Saccharomyces cerevisiae to obtain final ethanol concentrations above 70 g/l. Worked to develop a procedure to isolate water soluble arabinoxylan (A)X and water insoluble CRF fractions from barley hulls and straws by simple and economical steam treatment without using any acid or base. The yield of AX was lower than obtained by standard hydrogen peroxide technology used previously in our laboratory. Water binding properties of cellulosic residue fraction (CRF) and the emulsion stability studies of AX have been completed. CRF from both barley hulls and straws have high water holding capacity. The emulsion stabilities of AX from barley straws are superior to AX from barley hulls. Overall, all these AXs have good emulsion stabilizing capacity for oil-in-water emulsion system. Considerable research was conducted to identify functional lipid co-products in barley hulls and milling fractions, and initial research was conducted on identifying these compounds in barley straw.
1. Integrated process for production of fuel ethanol and value-added co-products from barley straw. Making fuel ethanol from non-food feedstocks like barley straw is a good idea since use of this feedstock doesn’t deplete food and feed supplies. Unfortunately, the present processes for making fuel ethanol from barley straw are too expensive to be commercialized. Therefore, ARS researchers at Wyndmoor, Pennsylvania developed a set of integrated processes to solve this problem by doing several simultaneous things: First, use of simple ammonia treatment was shown to make the barley straw more easily converted to fuel ethanol. Second, a new fermentation process was developed that made ethanol in much higher concentrations than previous processes, making the ethanol cheaper to distill. Third, the leftovers from the fermentation were “fed” to another microorganism, which ate them and produced a very valuable coproduct, an ingredient called “astaxanthin” used in aquaculture feeds. Use of all these new technologies together will make cellulosic ethanol from barley straw more profitable for the producer and more economical for the user. These results are being transferred to commercial partners who will share them with many companies trying to make cellulosic ethanol.
2. New barley varieties are low in troublesome “phytate” but not in other key nutrients. Phytate is a natural form of phosphorous found in barley kernels that is difficult for animals to digest. Animals fed barley diets excrete this phytate in their manure and the phytate results in pollution of streams and waterways. ARS and other breeders have now produced low-phytate barley cultivars which lessen this pollution problem. However, normal barley cultivars also contain nutrients and health-promoting compounds like cholesterol-lowering phytosterols, vitamin E, and beta-glucans which are important for the health and wellness of the animals and humans who consume barley. It was therefore necessary to show that low phytate barleys did not also contain lower levels of these important nutrients. ARS researchers at Wyndmoor, Pennsylvania and Aberdeen, Idaho analyzed both normal and low-phytate barleys and found that except for differences in the levels of phytate, other health-promoting nutrients were present in normal quantities in the low phytate barleys. Now growers, feeders, and grain processers can use low phytate barleys and be assured that the recipients of these grains will not be short changed on nutrition.
3. New method precisely removes hulls from barley without removing barley kernel nutrients. ARS researchers at Wyndmoor, Pennsylvnia developed a new milling method to precisely remove the low-value barley hull from barley kernels without removing valuable starch, protein, and vitamins from the kernel. The method uses a commercial milling device used in a new way to produce de-hulled barley kernels that are useful as feedstock for fuel ethanol production as well as superior as feed for monogastric animals. The method was given a Superior Paper Award by the American Society of Agricultural and Biological Engineers.
4. New method helps assure that food products labeled “made with whole grain” actually contain that health-promoting ingredient. Alkylresorcinols are natural molecules that occur in whole grains from wheat, barley, and other cereals and are now being used as “biomarkers” to identify foods that are prepared from whole grains. The existing method to measure the amount of alkylresorcinols in foods is slow and tedious. ARS researchers at Wyndmoor, Pennsylvania developed a new, automated, and fast method to measure alkylresorcinols in food products containing cooked and uncooked cereals. This work was published in 2012 in the Journal of Agriculture and Food Chemistry and will be useful for all who conduct research on these important biomarkers and will help to ensure the authenticity of whole grain food products.
Nghiem, N.P., Taylor, F., Hicks, K.B., Johnston, D., Shetty, J. 2011. Scale-up of ethanol production from winter barley by the EDGE (enhanced dry grind enzymatic) process in fermentors up to 300 liters. Applied Biochemistry and Biotechnology. 165:870-882.