Simultaneous saccharification and fermentation (SSF) is recognized as an efficient approach to the cost-effective conversion of biomass to fuel ethanol. This methodology takes advantage of the relief in end-product inhibition realized by conducting cellulose hydrolysis and glucose fermentation in the same well-stirred vessel. In this study, 15 species of hardwoods and softwoods were collected from sawmills located in the Appalachian region of the southern United States. These wood samples were air-dried to 8-10% moisture, pretreated using a dilute sulfuric acid cooking scheme at 160 degrees C, exhaustively washed, and applied to SSF with Saccharomyces cerevisiae D,A. Although the glucan content of each wood was found to be relatively invariant throughout the samples tested, hemicellulosic sugar and lignin contents were unique to each wood. These and other differences in chemical composition were related to resulting ethanol yields from SSF.