2012 Annual Report 1a.Objectives (from AD-416): To demonstrate that fractionation of biomass to produce an enriched xylan stream is compatible with cellulose conversion into ethanol and, furthermore, with high conversion efficiencies. 1b.Approach (from AD-416): 1. The generated material will be enzymatically hydrolyzed using commercial cellulases and fermented into ethanol using Saccharomyces cerevisiae yeast. 2. A carbohydrate and ethanol mass balance will be set up around the incoming biomass and outgoing ethanol; this balance will be used to solve the process efficiency for conversion of biomass into ethanol. 3.Progress Report: Hot-water extraction was evaluated as a method for generating xylan oligomers for the perennial grass Miscanthus. Extraction conditions have been optimized for reaction temperature and time. The extracted xylan oligomers have been analyzed for carbohydrate yield and average molecular weight.