Browsing by Author "Khatibi, Piyum A."

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    Conversion of deoxynivalenol to 3-acetyldeoxynivalenol in barley derived fuel ethanol co-products with yeast expressing trichothecene 3-O-acetyltransferases
    Khatibi, Piyum A.; Montanti, Justin; Nghiem, Nhuan P.; Hicks, Kevin B.; Berger, Gregory L.; Brooks, Wynse S.; Griffey, Carl A.; Schmale, David G. III (2011-09-02)
    Background The trichothecene mycotoxin deoxynivalenol (DON) may be concentrated in distillers dried grains with solubles (DDGS; a co-product of fuel ethanol fermentation) when grain containing DON is used to produce fuel ethanol. Even low levels of DON (≤ 5 ppm) in DDGS sold as feed pose a significant threat to the health of monogastric animals. New and improved strategies to reduce DON in DDGS need to be developed and implemented to address this problem. Enzymes known as trichothecene 3-O-acetyltransferases convert DON to 3-acetyldeoxynivalenol (3ADON), and may reduce its toxicity in plants and animals. Results Two Fusarium trichothecene 3-O-acetyltransferases (FgTRI101 and FfTRI201) were cloned and expressed in yeast (Saccharomyces cerevisiae) during a series of small-scale ethanol fermentations using barley (Hordeum vulgare). DON was concentrated 1.6 to 8.2 times in DDGS compared with the starting ground grain. During the fermentation process, FgTRI101 converted 9.2% to 55.3% of the DON to 3ADON, resulting in DDGS with reductions in DON and increases in 3ADON in the Virginia winter barley cultivars Eve, Thoroughbred and Price, and the experimental line VA06H-25. Analysis of barley mashes prepared from the barley line VA04B-125 showed that yeast expressing FfTRI201 were more effective at acetylating DON than those expressing FgTRI101; DON conversion for FfTRI201 ranged from 26.1% to 28.3%, whereas DON conversion for FgTRI101 ranged from 18.3% to 21.8% in VA04B-125 mashes. Ethanol yields were highest with the industrial yeast strain Ethanol Red®, which also consumed galactose when present in the mash. Conclusions This study demonstrates the potential of using yeast expressing a trichothecene 3-O-acetyltransferase to modify DON during commercial fuel ethanol fermentation.
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    Survey of Mycotoxins in Corn Distillers’ Dried Grains with Solubles from Seventy-Eight Ethanol Plants in Twelve States in the U.S. in 2011
    Khatibi, Piyum A.; McMaster, Nicole J.; Musser, Robert; Schmale, David G. III (MDPI, 2014-03-26)
    Fuel ethanol co-products known as distillers’ dried grains with solubles (DDGS) are a significant source of energy, protein, and phosphorous in animal feed. Fuel ethanol production may concentrate mycotoxins present in corn into DDGS. One hundred and forty one corn DDGS lots collected in 2011 from 78 ethanol plants located in 12 states were screened for the mycotoxins deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-ADON), 3-acetyldeoxynivalenol (3-ADON), nivalenol (NIV), and zearalenone (ZON). DON ranged from <0.50 to 14.62 μg g−1, 15-ADON ranged from <0.10 to 7.55 μg g−1, and ZON ranged from <0.10 to 2.12 μg g−1. None of the DDGS lots contained 3-ADON or NIV. Plants in OH had the highest levels of DON overall (mean of 9.51 μg g−1), and plants in NY, MI, IN, NE, and WI had mean DON levels >1 and <4 μg g−1. Twenty six percent (36/141) of the DDGS lots contained 1.0 to 5.0 μg g−1 DON, 2% (3/141) contained >5.0 and <10.0 μg g−1 DON, and 3% (4/141) contained >10.0 μg g−1 DON. All DDGS lots contaminated with unacceptable levels of DON evaded detection prior to their commercial distribution and were likely sold as feed products.