Selecting winter wheat straw for cellulosic ethanol production in the Pacific Northwest, USA

Selection of the best wheat variety for cellulosic ethanol production is very important. With dozens of varieties available, information on the sugar yield of different straws is needed to help farmers choose the most profitable wheat variety, for both grain yield and straw yield. Thirty winter wheat lines from the Pacific Northwest of the US were chosen for analysis based on historical and current production. Two pretreatment methods, dilute acid and hot water, were compared to determine the optimum pretreatment condition for wheat straw. Using the optimum dilute acid pretreatment condition, sugar yields from the straw of the 30 wheat varieties were compared. The differences in variety performance were then evaluated based on relationships among several measured parameters, including straw yield, grain yield, and chemical composition of biomass. The ranges of chemical composition for the 30 wheat straw varieties were 33.7-36.3% glucan (proxy for cellulose), 16.8-19.5% xylan (proxy for hemicellulose), and 18.4-20.6% lignin. Results also showed significant differences in total sugar recovery, which varied between 0.239 and 0.401 g g(-1) dry matter of raw biomass across wheat straw varieties. Among the 30 tested varieties, Weatherford was selected as the best for dual-purpose wheat because it ranked highest in straw yield and potential sugar production per area and 6th-highest in grain yield.