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Use of corn with high amino acid content for bioethanol production
D. RAMCHANDRAN (1), S. Moose (1), C. Parsons (1), V. Singh (1) (1) University of Illinois, Urbana, IL, U.S.A..

Amino acids, Lysine and Tryptophan, are limited in corn distillers dried grains with solubles (DDGS). These amino acids are currently added as supplements to enhance the nutritional value of DDGS. Corn with higher levels of these amino acids is of particular interest to the livestock and poultry community. The objectives of this study were to evaluate transgenic corn hybrids (with high Lys and Trp contents) for ethanol yields and nutritional value of DDGS. Two corn hybrids (I and II) and their transgenic (<i>TG</i>) isolines (I:<i>TG </i>and II:<i>TG</i>) were processed using laboratory scale procedures: conventional dry grind and modified dry grind process using granular starch hydrolyzing enzyme (GSHE). Crude protein contents of transgenic hybrids I:<i>TG</i> and II:<i>TG</i> (13.3 and 11.5%) were higher than their control isolines (9.70 and 10.8%). Total Lys and Trp contents in corn were 2.5 and 3.5 times higher in transgenic hybrids I and II than their control isolines, respectively. Final ethanol yields for transgenic hybrid I:<i>TG</i> were 16.7 and 16.1% v/v with conventional dry grind and GSHE process, respectively. This was lower compared to its control isolines: 18.5 and 17.8% v/v with conventional and GSHE process, respectively. Final ethanol yield of transgenic hybrid II:<i>TG</i> was 16.3% and lower than the control isoline (17.4% v/v) with conventional process. However, with GSHE process, ethanol yield for transgenic hybrid (II: <i>TG</i>) (17.5% v/v) was similar to its control isoline (17.1% v/v). There were no differences in the amino acid profiles in the recovered DDGS from conventional and GSHE processes. Total Lys and Trp contents for transgenic hybrids were in the range of 1.35 to 1.53% w/w and 0.31 to 0.38% w/w, respectively and are higher than the amino acid levels in normal DDGS (an average of 0.7 to 0.8% Lys and 0.2% Trp) and meet the necessary nutritional requirements for broilers and egg layers.