Reduction of the Mycotoxin Deoxynivalenol (DON) in Barley Derived Fuel Ethanol Co-Products

Non-Technical Summary:<br/>
Distiller's dried grains with solubles (DDGS), a co-product of fuel ethanol fermentation, are used for animal feed and human food. Fuel ethanol production may concentrate mycotoxins such as deoxynivalenol (DON) in DDGS, posing a significant threat to the health of domestic animals and humans consuming contaminated DDGS. DON is toxic in very small amounts, causing vomiting, reproductive problems, and even death. Barley is an important feedstock for fuel ethanol in the eastern U.S., but little is known about the fate of DON in barley across the farm-fuel-food continuum. The proposed research will identify potential risk factors for DON contamination and evaluate pre-harvest and post-harvest strategies for reducing DON in barley and DDGS. The specific objectives of this project are to: (1) monitor DON in field-grown hulled and hulless barley lines destined for fuel ethanol and DDGS production; (2) measure the impact of fuel ethanol production on DON levels in DDGS; (3) evaluate hull removal strategies to reduce DON levels in raw barley kernels prior to fuel ethanol production, and (4) track DON in commercial lots of raw barley, milled barley, and DDGS. The project aims to initiate a change in practice in which new and improved barley cultivars will be grown in Virginia, a change in knowledge in which agricultural professionals and grain end users in Virginia become aware of DON in barley and DDGS, and a change in conditions in which commercial ethanol plants in Virginia implement new tools and techniques to manage DON-contaminated barley and DDGS used in animal feed and human food.
<P>
Approach:<br/>
In Objective 1, we will monitor DON in newly developed barley lines using gas chromatography/mass spectrometry (GC/MS). Regulatory levels for DON in barley-derived DDGS have not yet been determined. Barley accessions having low, medium, and high levels of DON will be selected for fuel ethanol and DDGS production. This objective will deliver practical pre-harvest strategies to mitigate mycotoxin contamination in DDGS; we expect to identify barley genotypes having FHB resistance and inherently lower levels of DON.
<br/>In Objective 2, we will ferment small batches of field-grown barley grain and DON levels in the resulting DDGS will be quantified. This objective will deliver an increased knowledge of the transfer of DON from raw barley kernels to DDGS and to see if DON levels have any significant impact on fermentations, ethanol yields, and DDGS composition; we expect that DON will be concentrated in DDGS following fuel ethanol production.
<br/>In Objective 3, we will use different milling strategies to remove hulls from barley grain. DON will be quantified for fractions (untreated kernels with hulls, kernels without hulls, and hulls without kernels). This objective will deliver practical post-harvest strategies to mitigate DON contamination; we expect that the removal of hulls will reduce DON in resulting DDGS and that precision dehulling methods may provide better mitigation strategies than previously used non-selective abrasive milling technology.
<br/>In Objective 4, we will track DON in large commercial grain lots from farmers and grain distributors in Virginia and other states in the mid-Atlantic through ethanol and DDGS production. This objective will assess the real-world importance of pre-harvest and post-harvest intervention strategies to reduce DON across the farm-fuel-food continuum.
<P>
Progress:<br/>
2011/10 TO 2012/09<br/>
OUTPUTS: Fusarium Head Blight (FHB) incidence, FHB index, and Deoxynivalenol (DON) levels of Virginia hulled and hulless barley genotypes were evaluated in FHB nurseries in Virginia. Grain samples were harvested and analyzed for toxins, and a subset of these samples was processed for ethanol and DDGS. Hulls were removed from a set of hulled barley grain lots using precision dehulling and improved roller milling methods. Toxins were quantified from different fractions (untreated kernels with hulls, kernels without hulls, and hulls without kernels). A toxin detoxification gene was expressed in yeast to reduce toxin contamination in DDGS during fuel ethanol production. Toxins were measured in corn DDGS from ethanol plants throughout the U.S. PARTICIPANTS: Schmale is the PI for this Hatch project. Research Associate Niki McMaster quantified mycotoxins in samples using GC/MS, and former postdoctoral research associate Piyum Khatibi analyzed data and contributed writing to publications.
<br/>COLLABORATORS AND CONTACTS. Schmale has worked closely with Dr. Carl Griffey in the CSES department and Virginia Tech to develop and test new cultivars of wheat and barley, and with Dr. Kevin Hicks with the USDA in PA for milling strategies for barley.
<br/>TRAINING OR PROFESSIONAL DEVELOPMENT. Research associate Niki McMaster acquired new skills and developed new protocols on the GC/MS for mycotoxin detection and quantification.
<br/>TARGET AUDIENCES: Our project will continue to increase public awareness of mycotoxin contamination in ethanol co-products used in feed and food. <br/>PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
<P>
IMPACT: A barley-based ethanol market continues to provide potential for new opportunities and increased production of winter barley in the Eastern United States. This will not only create an important market for barley throughout the Eastern United States, it will provide valuable byproducts including carbon dioxide, fuel pellets, high protein feed ingredients for domestic animals, and enriched food products for human consumption. With the cost of feed ingredients on the rise, animal producers are contemplating lower cost options and therefore barley specifically aimed at the feed market could provide an alternative feed crop for animal producers. This also will create greater market demand for barley. Knowledge, techniques, and products resulting from our research are aimed at providing barley producers and grains, feed, food, and biofuel industries with a means to diminish mycotoxin levels and losses in grain yields and quality. Novel technologies were developed and deployed to enhance ethanol production and mitigate mycotoxins in DDGS, adding economic value and assurance of product safety in barley ethanol co-products. Our work will assist in providing long-range improvements in Virginia agriculture and food systems through a change in practice in which mycotoxin reduction in co-products becomes a priority for ethanol plants, a change in knowledge in which agricultural professionals and grain end users become aware of DON in ethanol co-products destined for domestic animal feeds and human foods, and a change in conditions in which yeast expressing mycotoxin detoxification proteins can be incorporated into standard fuel ethanol plants. Our project will also increase public awareness of mycotoxin contamination in VA in ethanol co-products used in feed and food.