Sunday, April 29, 2007

Evaluating the potential for the utilization of genetic modified straws for bio-ethanol production

Yan Liu1, Wei Liao2, Robert Zemetra3, Thomas Keohler3, and Shulin Chen1. (1) Department of Biological System Engineering, Washington State University, L.J. Smith 213, Pullman, WA 99163, (2) Department of Biosystems and Agricultural Engineering, Michigan State University, 202 Farrall Hall, East Lansing, MI 48824, (3) Department of Plant, Soil & Entomological Sciences, University of Idaho, University of Idaho, PO Box 442339, Moscow, ID, 83844-2339

The primary challenge of bio-ethanol production from lignocellulosic feedstocks is the presence of lignin in the straw which limits its usefulness as a source of fermentable sugars.  Reduction of the lignin in the straw would improve accessibility to the cellulosic polysaccharides and improve the efficiency of the fermentation process. The objectives of this study are: 1). To study the effects of different genetic modification on lignin content of wheat and barley straw and ; 2). Evaluate the ethanol production from the genetically modified straw.  Two types of genetic modifications, low phytic acid mutants in both wheat and barley and transgenic wheat carrying an anti-sense gene for cinnamoyl-CoA reductase (CCR1), have been developed.  The low phytic acid mutants appear to affect a gene involved with inositol synthesis which is an upstream precursor for lignin biosynthesis while the CCR1 gene is directly involved in the lignin biosynthetic pathway. The experiment consists of growing the two cereals in two locations using a randomized complete block design with 4 replications over two years.   There were 15 wheat entries (12 low phytic acid traits, two transgenics and one control) and 12 barley entries (6 low phytic acid mutant lines and 6 wildtype lines). Agronomic data (heading date, height, yield and test weight) was collected.  Straw was harvested and analyzed for contents of lignin, hemicellulose, cellulose, and ash.  A simultaneous saccharification and fermentation process was used to determine the ethanol production potential of the straw. The results of the first year’s study will be discussed.