1a. Objectives (from AD-416):
Develop new hulled and hulless barley lines having traits desirable to enhance production of fuel ethanol and add value to the animal feed coproduct, DDGS; engineer commercial ethanol yeasts to detoxify mycotoxins such as DON that are sometimes found on barley kernels in wet growing years and that would be detrimental to animals who ate the resulting ethanol coproduct, DDGS, derived from that grain and; evaluate hull removal strategies to reduce DON levels in raw barley kernels prior to fuel ethanol production as another way to reduce levels of DON in DDGS.
1b. Approach (from AD-416):
Virginia Tech breeders will send new barley varieties to us for evaluation. Varieties containing high levels of starch, beta-glucan, and protein will be fermented to ethanol and the coproduct, DDGS. Varieties producing the highest ethanol yields and DDGS with highest protein will be selected as top candidates. Virginia Tech researchers will transform commercial ethanol yeasts with a 3-O-acetyltransferase (TRI101) enzyme, which catalyzes the acetylation of DON at the third carbon, reducing the toxicity of DON by two orders of magnitude. We will test the ability of these yeasts to detoxify DON during a series of small-scale ethanol fermentations using raw barley grain containing different levels of DON. We expect the enzyme to detoxify DON during simultaneous saccharification and fermentation. It is expected that the use of these transgenic yeasts during fermentation will add additional value by the production of barley DDGS with low DON levels. ERRC researchers will remove barley hulls using several different types of mills (pearling, roller milling, precision impact mill) to determine if removal of hull will result in barley kernels with lower DON levels.
3. Progress Report:
During the year, ARS researchers at Wyndmoor worked with the team at Virginia Tech to develop a process to remove toxic mycotoxins from Fusarium-infected, field-grown hulled barley so it can be used for fuel and feed purposes. The hypothesis tested was that removal of the hull from the barley kernel would also remove most of the mycotoxins from the barley. Two different hull removal processes were used which included roller milling followed by sieving and a “precision” dehulling process previously developed by ARS researchers. The precision milling process was far more effective than the roller milling process at removing mycotoxins from hulled barley, removing the hull and up to 85% of the mycotoxins without significant loss of important kernel components such as starch and protein. This work has been described in a manuscript that has been submitted to a peer reviewed journal.