Abstract: In one aspect, a process for treating woody plant material is provided, the process involving contacting the plant material with a continuous flow of an aqueous ethanol solution at elevated temperature and pressure under conditions that promote extraction of ethanol-soluble lignin from the plant material and retention of hemicellulose sugars, xylose and cellulose in the treated plant material solids. In another aspect, a process for extracting hemicellulose sugars from lignin-depleted plant material solids is provided, the process involving contacting lignin-depleted plant material with water at elevated temperature and pressure under conditions that promote extraction of hemicellulose sugars from the plant material; and recovering hemicellulose sugars from the liquid mixture.

Abstract: An integrated process for the production of ethanol from woody plant material is provided, the process comprising: contacting a continuous flow of the plant material with a counter-current continuous flow of an aqueous ethanol solution at elevated temperature and pressure to provide plant material depleted of lignin; removing ethanol from the lignin-depleted plant material; contacting a continuous flow of the lignin-depleted plant material with water at elevated temperature and pressure to solubilize xylose within the plant material; and hydrolyzing cellulose present in the plant material to form glucose, which in turn is fermented to produce ethanol.