Tuesday, April 30, 2013
Exhibit Hall
The nutrient composition during fermentation is very complex and important to cell viability and ethanol production. AFEX™ pretreated corn stover has been shown to contain the necessary nutrient profile for sufficient growth and fermentability for Saccharomyces cerevisiae. Yeast extract is viewed as the ideal nutrient source but it is impractical due to its cost and to a lesser extent to the fact that it stimulates growth. Growth is necessary but can divert too much of the carbon source away from the desired product. The goal of this research was to investigate nutrients that allow the yeast to ferment more of the xylose present in lignocellulose hydrolsyates. Xylose fermenting pathways are easily inhibited by moderately high ethanol concentrations. Additional nutrients can provide yeast with the ability to resist damage to the cell membrane and also produce protective proteins. The nutrients tested have been selected based on price, evidence of effectiveness against ethanol inhibition, and/or because they are common enzyme cofactors.