Submitted to: Cold Spring Harbor Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 19, 2007
Publication Date: August 19, 2007
Citation: Hector, R.E., Qureshi, N., Hughes, S.R., Cotta, M.A. 2007. Engineering Saccharomyces cerevisiae for ethanol production from agricultural waste products [abstract]. Yeast Cell Biology. Paper No. 176. Technical Abstract: Research focusing on the production of alternative fuels has intensified due to increasing global demand for a limited oil supply. Fuel ethanol production in the U.S. amounted to 5 billion gallons for 2006 and is projected to increase. Most of the ethanol produced is currently from fermentation of corn grain with an estimated 17% of the corn crop going to the production of ethanol. Using the entire U.S. corn crop for ethanol production would displace about 20% of the current transportation fuel needs but would have severe economic consequences. To increase fuel ethanol production and move beyond the use of corn grain, technologies are being developed for converting biomass, such as corn stalks and wheat straw, to ethanol. Saccharomyces cerevisiae can produce ethanol from glucose but it cannot utilize five-carbon sugars that make up the hemicellulose component of biomass feedstocks. Hemicellulose can make up to 20-30% of biomass**1 and is primarily composed of xylose. Enzymes from native xylose assimilating organisms have been transferred to S. cerevisiae allowing fermentation of xylose.**2 Efficient conversion of xylose to ethanol is still limited by multiple issues including cellular redox imbalance, lack of xylose specific transporters, and low flux of xylose into the pentose phosphate pathway. To address some of these issues, we have created strains expressing heterologous xylose transporters and modifications that alter the NAD**+/NADH ratio. Xylose consumption using these strains will be presented. 1. Saha, B.C., J. Ind. Microbiol. Biotechnol., 30:279-291, 2003. 2. Jeffries, T.W., Curr. Opinion Biotechnol., 17:320-326, 2006.